* [PATCH v8 01/25] KVM: arm64: Donate MMIO to the hypervisor
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 02/25] iommu/arm-smmu-v3: Move Queue and STE functions to header Mostafa Saleh
` (24 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add a function to donate MMIO to the hypervisor so IOMMU hypervisor
drivers can protect and access the MMIO of IOMMUs.
As donating MMIO is very rare, and we don't need to encode the full
state, it's reasonable to have a separate function to do this.
It will init the host s2 page table with an invalid leaf with the owner ID
to prevent the host from mapping the page on faults.
Also, prevent kvm_pgtable_stage2_unmap() from removing owner ID from
stage-2 PTEs, as this can be triggered from recycle logic under memory
pressure. There is no code relying on this, as all ownership changes are
done via host_stage2_set_owner_locked().
For the error path in IOMMU drivers, add a function to donate MMIO
back from hyp to host. However, that leaks the hypervisor virtual
address range which should be acceptable as this is quite rare and
it matches the behaviour of fix_map/block.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/include/asm/kvm_pgtable.h | 1 +
arch/arm64/kvm/hyp/include/nvhe/mem_protect.h | 7 ++
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 93 ++++++++++++++++++-
arch/arm64/kvm/hyp/pgtable.c | 11 +--
4 files changed, 105 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 41a8687938eb..223072b3e2cd 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -712,6 +712,7 @@ int kvm_pgtable_stage2_annotate(struct kvm_pgtable *pgt, u64 addr, u64 size,
* containing the cleared entry is decremented, with unreferenced pages being
* freed. Unmapping a cacheable page will ensure that it is clean to the PoC if
* FWB is not supported by the CPU.
+ * This function can't be used to clear invalid counted PTEs (annotations).
*
* Return: 0 on success, negative error code on failure.
*/
diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
index 29935c7da1de..072f4b0e72c2 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h
@@ -36,6 +36,13 @@ int __pkvm_guest_share_host(struct pkvm_hyp_vcpu *vcpu, u64 gfn);
int __pkvm_guest_unshare_host(struct pkvm_hyp_vcpu *vcpu, u64 gfn);
int __pkvm_host_unshare_hyp(u64 pfn);
int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages);
+/*
+ * Donate MMIO range to the hypervisor, it will be mapped in the hypervisor's
+ * private range and unmapped from the host stage-2.
+ */
+int __pkvm_host_donate_hyp_mmio(u64 pfn, u64 nr_pages, unsigned long *haddr);
+/* Remaps MMIO range in the host, typically used in error path. */
+int __pkvm_hyp_donate_host_mmio(u64 pfn, u64 nr_pages);
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages);
int __pkvm_host_share_ffa(u64 pfn, u64 nr_pages);
int __pkvm_host_unshare_ffa(u64 pfn, u64 nr_pages);
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index 39aa8911f62c..c1a8fd811c0f 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -385,7 +385,11 @@ static int host_stage2_unmap_dev_all(void)
u64 addr = 0;
int i, ret;
- /* Unmap all non-memory regions to recycle the pages */
+ /*
+ * Unmap all non-memory regions to recycle the pages.
+ * That relies on kvm_pgtable_stage2_unmap() not clearing
+ * counted PTEs which include hypervisor MMIO.
+ */
for (i = 0; i < hyp_memblock_nr; i++, addr = reg->base + reg->size) {
reg = &hyp_memory[i];
ret = kvm_pgtable_stage2_unmap(pgt, addr, reg->base - addr);
@@ -1126,6 +1130,93 @@ int __pkvm_host_donate_hyp(u64 pfn, u64 nr_pages)
return ret;
}
+int __pkvm_host_donate_hyp_mmio(u64 pfn, u64 nr_pages, unsigned long *haddr)
+{
+ u64 phys = hyp_pfn_to_phys(pfn);
+ u64 size = PAGE_SIZE * nr_pages;
+ kvm_pte_t pte;
+ u64 offset;
+ int ret;
+
+ /* Only before de-privilege. */
+ if (static_branch_unlikely(&kvm_protected_mode_initialized))
+ return -EPERM;
+
+ if (!pfn_range_is_valid(pfn, nr_pages))
+ return -EINVAL;
+
+ ret = __pkvm_create_private_mapping(phys, size, PAGE_HYP_DEVICE, haddr);
+ if (ret)
+ return ret;
+
+ host_lock_component();
+ for (offset = 0; offset < size; offset += PAGE_SIZE) {
+ if (addr_is_memory(phys + offset)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ ret = kvm_pgtable_get_leaf(&host_mmu.pgt, phys + offset, &pte, NULL);
+ if (ret)
+ goto unlock;
+ if (pte && !kvm_pte_valid(pte)) {
+ ret = -EPERM;
+ goto unlock;
+ }
+ }
+ /*
+ * We set HYP as the owner of the MMIO pages in the host stage-2, for:
+ * - host aborts: host_stage2_adjust_range() would fail for invalid non zero PTEs.
+ * - recycle under memory pressure: host_stage2_unmap_dev_all() would call
+ * kvm_pgtable_stage2_unmap() which will not clear non zero invalid ptes (counted).
+ * - other MMIO donation: Would fail as we check that the PTE is valid or empty.
+ */
+ ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
+ phys, size, &host_s2_pool,
+ KVM_HOST_INVALID_PTE_TYPE_DONATION,
+ FIELD_PREP(KVM_HOST_DONATION_PTE_OWNER_MASK, PKVM_ID_HYP));
+unlock:
+ host_unlock_component();
+ return ret;
+}
+
+int __pkvm_hyp_donate_host_mmio(u64 pfn, u64 nr_pages)
+{
+ u64 phys = hyp_pfn_to_phys(pfn);
+ u64 size = PAGE_SIZE * nr_pages;
+ kvm_pte_t pte;
+ u64 offset;
+ int ret = 0;
+
+ if (static_branch_unlikely(&kvm_protected_mode_initialized))
+ return -EPERM;
+
+ if (!pfn_range_is_valid(pfn, nr_pages))
+ return -EINVAL;
+
+ host_lock_component();
+ for (offset = 0; offset < size; offset += PAGE_SIZE) {
+ if (addr_is_memory(phys + offset)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ ret = kvm_pgtable_get_leaf(&host_mmu.pgt, phys + offset, &pte, NULL);
+ if (ret)
+ goto unlock;
+ if (!pte || kvm_pte_valid(pte)) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+ if (FIELD_GET(KVM_HOST_DONATION_PTE_OWNER_MASK, pte) != PKVM_ID_HYP) {
+ ret = -EPERM;
+ goto unlock;
+ }
+ }
+ WARN_ON(host_stage2_idmap_locked(phys, size, PKVM_HOST_MMIO_PROT));
+unlock:
+ host_unlock_component();
+ return ret;
+}
+
int __pkvm_hyp_donate_host(u64 pfn, u64 nr_pages)
{
u64 phys = hyp_pfn_to_phys(pfn);
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index b74dd5ce1efd..25af105855e5 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1161,13 +1161,12 @@ static int stage2_unmap_walker(const struct kvm_pgtable_visit_ctx *ctx,
kvm_pte_t *childp = NULL;
bool need_flush = false;
- if (!kvm_pte_valid(ctx->old)) {
- if (stage2_pte_is_counted(ctx->old)) {
- kvm_clear_pte(ctx->ptep);
- mm_ops->put_page(ctx->ptep);
- }
+ /*
+ * This check ignores stage2_pte_is_counted() instead of clearing
+ * the PTE as it might be MMIO owned by the hypervisor.
+ */
+ if (!kvm_pte_valid(ctx->old))
return 0;
- }
if (kvm_pte_table(ctx->old, ctx->level)) {
childp = kvm_pte_follow(ctx->old, mm_ops);
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 02/25] iommu/arm-smmu-v3: Move Queue and STE functions to header
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 01/25] KVM: arm64: Donate MMIO to the hypervisor Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 18:23 ` Nicolin Chen
2026-09-22 13:12 ` [PATCH v8 03/25] iommu/arm-smmu-v3: Introduce RangeInval encoding helpers Mostafa Saleh
` (23 subsequent siblings)
25 siblings, 1 reply; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The KVM SMMUv3 driver would re-use some of the CMDQ and STE code
inside the hypervisor. Move those functions to the header file that
would be shared between the host kernel and the hypervisor.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 59 --------------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 62 +++++++++++++++++++++
2 files changed, 62 insertions(+), 59 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 5732f3ba0122..df1924969212 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -134,33 +134,6 @@ static void parse_driver_options(struct arm_smmu_device *smmu)
}
/* Low-level queue manipulation functions */
-static bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
-{
- u32 space, prod, cons;
-
- prod = Q_IDX(q, q->prod);
- cons = Q_IDX(q, q->cons);
-
- if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
- space = (1 << q->max_n_shift) - (prod - cons);
- else
- space = cons - prod;
-
- return space >= n;
-}
-
-static bool queue_full(struct arm_smmu_ll_queue *q)
-{
- return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
- Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
-}
-
-static bool queue_empty(struct arm_smmu_ll_queue *q)
-{
- return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
- Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
-}
-
static bool queue_consumed(struct arm_smmu_ll_queue *q, u32 prod)
{
return ((Q_WRP(q, q->cons) == Q_WRP(q, prod)) &&
@@ -179,12 +152,6 @@ static void queue_sync_cons_out(struct arm_smmu_queue *q)
writel_relaxed(q->llq.cons, q->cons_reg);
}
-static void queue_inc_cons(struct arm_smmu_ll_queue *q)
-{
- u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
- q->cons = Q_OVF(q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
-}
-
static void queue_sync_cons_ovf(struct arm_smmu_queue *q)
{
struct arm_smmu_ll_queue *llq = &q->llq;
@@ -216,12 +183,6 @@ static int queue_sync_prod_in(struct arm_smmu_queue *q)
return ret;
}
-static u32 queue_inc_prod_n(struct arm_smmu_ll_queue *q, int n)
-{
- u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + n;
- return Q_OVF(q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
-}
-
static void queue_poll_init(struct arm_smmu_device *smmu,
struct arm_smmu_queue_poll *qp)
{
@@ -249,14 +210,6 @@ static int queue_poll(struct arm_smmu_queue_poll *qp)
return 0;
}
-static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
-{
- int i;
-
- for (i = 0; i < n_dwords; ++i)
- *dst++ = cpu_to_le64(*src++);
-}
-
static void queue_read(u64 *dst, __le64 *src, size_t n_dwords)
{
int i;
@@ -1796,18 +1749,6 @@ static void arm_smmu_free_cd_tables(struct arm_smmu_master *master)
}
/* Stream table manipulation functions */
-static void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
- dma_addr_t l2ptr_dma)
-{
- u64 val = 0;
-
- val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, STRTAB_SPLIT + 1);
- val |= l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK;
-
- /* The HW has 64 bit atomicity with stores to the L2 STE table */
- WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
-}
-
struct arm_smmu_ste_writer {
struct arm_smmu_entry_writer writer;
u32 sid;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index dd2fee2f560e..5b23f6ee78d4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1223,6 +1223,68 @@ int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
bool sync);
bool arm_smmu_erratum_repeat_tlbi_cfgi(void);
+/* Queue and STE functions shared between kernel and hyp. */
+static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+{
+ u32 space, prod, cons;
+
+ prod = Q_IDX(q, q->prod);
+ cons = Q_IDX(q, q->cons);
+
+ if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
+ space = (1 << q->max_n_shift) - (prod - cons);
+ else
+ space = cons - prod;
+
+ return space >= n;
+}
+
+static inline bool queue_full(struct arm_smmu_ll_queue *q)
+{
+ return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
+ Q_WRP(q, q->prod) != Q_WRP(q, q->cons);
+}
+
+static inline bool queue_empty(struct arm_smmu_ll_queue *q)
+{
+ return Q_IDX(q, q->prod) == Q_IDX(q, q->cons) &&
+ Q_WRP(q, q->prod) == Q_WRP(q, q->cons);
+}
+
+static inline u32 queue_inc_prod_n(struct arm_smmu_ll_queue *q, int n)
+{
+ u32 prod = (Q_WRP(q, q->prod) | Q_IDX(q, q->prod)) + n;
+
+ return Q_OVF(q->prod) | Q_WRP(q, prod) | Q_IDX(q, prod);
+}
+
+static inline void queue_inc_cons(struct arm_smmu_ll_queue *q)
+{
+ u32 cons = (Q_WRP(q, q->cons) | Q_IDX(q, q->cons)) + 1;
+
+ q->cons = Q_OVF(q->cons) | Q_WRP(q, cons) | Q_IDX(q, cons);
+}
+
+static inline void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
+{
+ int i;
+
+ for (i = 0; i < n_dwords; ++i)
+ *dst++ = cpu_to_le64(*src++);
+}
+
+static inline void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
+ dma_addr_t l2ptr_dma)
+{
+ u64 val = 0;
+
+ val |= FIELD_PREP(STRTAB_L1_DESC_SPAN, STRTAB_SPLIT + 1);
+ val |= l2ptr_dma & STRTAB_L1_DESC_L2PTR_MASK;
+
+ /* The HW has 64 bit atomicity with stores to the L2 STE table */
+ WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
+}
+
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
void arm_smmu_sva_notifier_synchronize(void);
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* Re: [PATCH v8 02/25] iommu/arm-smmu-v3: Move Queue and STE functions to header
2026-09-22 13:12 ` [PATCH v8 02/25] iommu/arm-smmu-v3: Move Queue and STE functions to header Mostafa Saleh
@ 2026-09-22 18:23 ` Nicolin Chen
0 siblings, 0 replies; 31+ messages in thread
From: Nicolin Chen @ 2026-09-22 18:23 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jgg, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Tue, Sep 22, 2026 at 01:12:35PM +0000, Mostafa Saleh wrote:
> The KVM SMMUv3 driver would re-use some of the CMDQ and STE code
> inside the hypervisor. Move those functions to the header file that
> would be shared between the host kernel and the hypervisor.
>
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
^ permalink raw reply [flat|nested] 31+ messages in thread
* [PATCH v8 03/25] iommu/arm-smmu-v3: Introduce RangeInval encoding helpers
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 01/25] KVM: arm64: Donate MMIO to the hypervisor Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 02/25] iommu/arm-smmu-v3: Move Queue and STE functions to header Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 18:45 ` Nicolin Chen
2026-09-22 13:12 ` [PATCH v8 04/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
` (22 subsequent siblings)
25 siblings, 1 reply; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Move some of the RIL encodings into helpers so the hypervisor can
reuse them.
The hypervisor is going to have its own algorithm to determine the
sequence of RIL commands needed.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
I removed the refactoring from this patch as this code would be
deleted anyway.
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 14 +++-------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 30 +++++++++++++++++++++
2 files changed, 34 insertions(+), 10 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index df1924969212..2e54d1ba2566 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2418,8 +2418,7 @@ static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,
if (smmu->features & ARM_SMMU_FEAT_RANGE_INV) {
num_pages = size >> tg;
- /* Convert page size of 12,14,16 (log2) to 1,2,3 */
- tg_enc = (tg - 10) / 2;
+ tg_enc = arm_smmu_tlb_inv_tg_enc(tg);
/*
* Determine what level the granule is at. For non-leaf, both
@@ -2430,7 +2429,7 @@ static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,
* where both scale and num could be 0 as well.
*/
if (leaf)
- ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
+ ttl = arm_smmu_tlb_inv_ttl(granule, tg);
else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1)
num_pages++;
}
@@ -2452,10 +2451,8 @@ static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,
/* Determine how many chunks of 2^scale size we have */
num = (num_pages >> scale) & CMDQ_TLBI_RANGE_NUM_MAX;
- /* Keep the pre-DS 5-bit truncation when scale > 31 */
cmd->data[0] = orig_data0 |
- FIELD_PREP(CMDQ_TLBI_0_NUM, num - 1) |
- FIELD_PREP(CMDQ_TLBI_0_SCALE, scale & 0x1f);
+ arm_smmu_tlb_inv_range_enc(num, scale);
/* range is num * 2^scale * pgsize */
inv_range = num << (scale + tg);
@@ -2469,10 +2466,7 @@ static void arm_smmu_cmdq_batch_add_range(struct arm_smmu_device *smmu,
* command and something would be very broken if iova had them
* set.
*/
- cmd->data[1] = FIELD_PREP(CMDQ_TLBI_1_LEAF, leaf) |
- FIELD_PREP(CMDQ_TLBI_1_TTL, ttl) |
- FIELD_PREP(CMDQ_TLBI_1_TG, tg_enc) |
- (iova & ~GENMASK_U64(11, 0));
+ cmd->data[1] = arm_smmu_tlb_inv_addr(iova, leaf, ttl, tg_enc);
arm_smmu_cmdq_batch_add_cmd_p(smmu, cmds, cmd);
iova += inv_range;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 5b23f6ee78d4..f3e80d103ba1 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1285,6 +1285,36 @@ static inline void arm_smmu_write_strtab_l1_desc(struct arm_smmu_strtab_l1 *dst,
WRITE_ONCE(dst->l2ptr, cpu_to_le64(val));
}
+/* Convert page size of 12,14,16 (log2) to 1,2,3 */
+static inline u8 arm_smmu_tlb_inv_tg_enc(size_t tg)
+{
+ return (tg - 10) / 2;
+}
+
+/* Only valid for leaf invalidations, non-leaf must use TTL=0 */
+static inline u8 arm_smmu_tlb_inv_ttl(size_t granule, size_t tg)
+{
+ return 4 - ((ilog2(granule) - 3) / (tg - 3));
+}
+
+static inline u64 arm_smmu_tlb_inv_addr(unsigned long iova, bool leaf, u8 ttl, u8 tg_enc)
+{
+ return FIELD_PREP(CMDQ_TLBI_1_LEAF, leaf) |
+ FIELD_PREP(CMDQ_TLBI_1_TTL, ttl) |
+ FIELD_PREP(CMDQ_TLBI_1_TG, tg_enc) |
+ (iova & ~GENMASK_U64(11, 0));
+}
+
+/*
+ * @num: Number of 2^scale granules, must be >= 1.
+ */
+static inline u64 arm_smmu_tlb_inv_range_enc(u8 num, u8 scale)
+{
+ /* Keep the pre-DS 5-bit truncation when scale > 31 */
+ return FIELD_PREP(CMDQ_TLBI_0_NUM, num - 1) |
+ FIELD_PREP(CMDQ_TLBI_0_SCALE, scale & 0x1f);
+}
+
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
void arm_smmu_sva_notifier_synchronize(void);
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* Re: [PATCH v8 03/25] iommu/arm-smmu-v3: Introduce RangeInval encoding helpers
2026-09-22 13:12 ` [PATCH v8 03/25] iommu/arm-smmu-v3: Introduce RangeInval encoding helpers Mostafa Saleh
@ 2026-09-22 18:45 ` Nicolin Chen
0 siblings, 0 replies; 31+ messages in thread
From: Nicolin Chen @ 2026-09-22 18:45 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jgg, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Tue, Sep 22, 2026 at 01:12:36PM +0000, Mostafa Saleh wrote:
> +/* Convert page size of 12,14,16 (log2) to 1,2,3 */
> +static inline u8 arm_smmu_tlb_inv_tg_enc(size_t tg)
The prefix "arm_smmu_tlb_" is used by the iommu_flush_ops.
How about arm_smmu_cmd_tlbi_tg_enc?
> +static inline u64 arm_smmu_tlb_inv_addr(unsigned long iova, bool leaf, u8 ttl, u8 tg_enc)
> +{
> + return FIELD_PREP(CMDQ_TLBI_1_LEAF, leaf) |
> + FIELD_PREP(CMDQ_TLBI_1_TTL, ttl) |
> + FIELD_PREP(CMDQ_TLBI_1_TG, tg_enc) |
> + (iova & ~GENMASK_U64(11, 0));
> +}
This actually covers entire data1 than just "addr", so maybe
arm_smmu_cmd_tlbi_data1_enc?
> +/*
> + * @num: Number of 2^scale granules, must be >= 1.
> + */
Nit: single-line style
> +static inline u64 arm_smmu_tlb_inv_range_enc(u8 num, u8 scale)
> +{
> + /* Keep the pre-DS 5-bit truncation when scale > 31 */
> + return FIELD_PREP(CMDQ_TLBI_0_NUM, num - 1) |
> + FIELD_PREP(CMDQ_TLBI_0_SCALE, scale & 0x1f);
And this could be arm_smmu_cmd_tlbi_data0_enc that takes orig too,
matching with data1_enc().
Nicolin
^ permalink raw reply [flat|nested] 31+ messages in thread
* [PATCH v8 04/25] iommu/arm-smmu-v3: Move IDR parsing to common functions
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (2 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 03/25] iommu/arm-smmu-v3: Introduce RangeInval encoding helpers Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 19:45 ` Nicolin Chen
2026-09-22 13:12 ` [PATCH v8 05/25] iommu/arm-smmu-v3: Move hitless machinery to common code Mostafa Saleh
` (21 subsequent siblings)
25 siblings, 1 reply; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh,
Jason Gunthorpe
Move parsing of IDRs to functions so that it can be re-used
from the hypervisor.
As the new functions operate on structs from both the hypervisor
and the kernel which would be different, we rely on the compilation
unit to having ARM_SMMU_OBJ point to the correct struct; some
best-effort static asserts were added .
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/Makefile | 2 +-
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.c | 176 +++++++++++++++++
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.h | 31 +++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 179 ++----------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 6 +
5 files changed, 228 insertions(+), 166 deletions(-)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
diff --git a/drivers/iommu/arm/arm-smmu-v3/Makefile b/drivers/iommu/arm/arm-smmu-v3/Makefile
index 493a659cc66b..c9ce392e6d31 100644
--- a/drivers/iommu/arm/arm-smmu-v3/Makefile
+++ b/drivers/iommu/arm/arm-smmu-v3/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_ARM_SMMU_V3) += arm_smmu_v3.o
-arm_smmu_v3-y := arm-smmu-v3.o
+arm_smmu_v3-y := arm-smmu-v3.o arm-smmu-v3-common-lib.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_IOMMUFD) += arm-smmu-v3-iommufd.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_SVA) += arm-smmu-v3-sva.o
arm_smmu_v3-$(CONFIG_TEGRA241_CMDQV) += tegra241-cmdqv.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
new file mode 100644
index 000000000000..a341974e7aaf
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2015 ARM Limited
+ * Arm SMMUv3 driver functions shared with hypervisor.
+ */
+
+#include "arm-smmu-v3.h"
+#include "arm-smmu-v3-common-lib.h"
+
+void arm_smmu_device_iidr_probe(ARM_SMMU_OBJ *smmu)
+{
+ u32 reg;
+ unsigned int implementer, productid, variant, revision;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
+ implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
+ productid = FIELD_GET(IIDR_PRODUCTID, reg);
+ variant = FIELD_GET(IIDR_VARIANT, reg);
+ revision = FIELD_GET(IIDR_REVISION, reg);
+
+ switch (implementer) {
+ case IIDR_IMPLEMENTER_ARM:
+ switch (productid) {
+ case IIDR_PRODUCTID_ARM_MMU_600:
+ /* Arm erratum 1076982 */
+ if (variant == 0 && revision <= 2)
+ smmu->features &= ~ARM_SMMU_FEAT_SEV;
+ /* Arm erratum 1209401 */
+ if (variant < 2)
+ smmu->features &= ~ARM_SMMU_FEAT_NESTING;
+ break;
+ case IIDR_PRODUCTID_ARM_MMU_700:
+ /* Many errata... */
+ smmu->features &= ~ARM_SMMU_FEAT_BTM;
+ if (variant < 1 || revision < 1) {
+ /* Arm erratum 2812531 */
+ smmu->options |= ARM_SMMU_OPT_CMDQ_FORCE_SYNC;
+ /* Arm errata 2268618, 2812531 */
+ smmu->features &= ~ARM_SMMU_FEAT_NESTING;
+ }
+ break;
+ case IIDR_PRODUCTID_ARM_MMU_L1:
+ case IIDR_PRODUCTID_ARM_MMU_S3:
+ /* Arm errata 3878312/3995052 */
+ smmu->features &= ~ARM_SMMU_FEAT_BTM;
+ break;
+ }
+ break;
+ }
+}
+
+u32 arm_smmu_idr0_probe(ARM_SMMU_OBJ *smmu)
+{
+ u32 reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
+
+ /* 2-level structures */
+ if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
+ smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+ if (reg & IDR0_CD2L)
+ smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
+
+ /*
+ * Translation table endianness.
+ * We currently require the same endianness as the CPU, but this
+ * could be changed later by adding a new IO_PGTABLE_QUIRK.
+ */
+ switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
+ case IDR0_TTENDIAN_MIXED:
+ smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
+ break;
+#ifdef __BIG_ENDIAN
+ case IDR0_TTENDIAN_BE:
+ smmu->features |= ARM_SMMU_FEAT_TT_BE;
+ break;
+#else
+ case IDR0_TTENDIAN_LE:
+ smmu->features |= ARM_SMMU_FEAT_TT_LE;
+ break;
+#endif
+ }
+
+ /* Boolean feature flags */
+ if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
+ smmu->features |= ARM_SMMU_FEAT_PRI;
+
+ if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
+ smmu->features |= ARM_SMMU_FEAT_ATS;
+
+ if (reg & IDR0_SEV)
+ smmu->features |= ARM_SMMU_FEAT_SEV;
+
+ if (reg & IDR0_MSI)
+ smmu->features |= ARM_SMMU_FEAT_MSI;
+
+ if (reg & IDR0_HYP)
+ smmu->features |= ARM_SMMU_FEAT_HYP;
+
+ switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
+ case IDR0_STALL_MODEL_FORCE:
+ smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
+ fallthrough;
+ case IDR0_STALL_MODEL_STALL:
+ smmu->features |= ARM_SMMU_FEAT_STALLS;
+ }
+
+ if (reg & IDR0_S1P)
+ smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
+
+ if (reg & IDR0_S2P)
+ smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
+
+ if ((smmu->features & ARM_SMMU_FEAT_TRANS_S1) &&
+ (smmu->features & ARM_SMMU_FEAT_TRANS_S2))
+ smmu->features |= ARM_SMMU_FEAT_NESTING;
+
+ return reg;
+}
+
+void arm_smmu_idr3_probe(ARM_SMMU_OBJ *smmu)
+{
+ u32 reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
+
+ if (FIELD_GET(IDR3_RIL, reg))
+ smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
+ if (FIELD_GET(IDR3_FWB, reg))
+ smmu->features |= ARM_SMMU_FEAT_S2FWB;
+ if (FIELD_GET(IDR3_BBM, reg) == 2)
+ smmu->features |= ARM_SMMU_FEAT_BBML2;
+}
+
+u32 arm_smmu_idr5_probe(ARM_SMMU_OBJ *smmu)
+{
+ u32 reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);
+
+ if (reg & IDR5_DS)
+ smmu->features |= ARM_SMMU_FEAT_DS;
+
+ if (reg & IDR5_GRAN64K)
+ smmu->pgsize_bitmap |= SZ_64K | SZ_512M;
+ if (reg & IDR5_GRAN16K)
+ smmu->pgsize_bitmap |= SZ_16K | SZ_32M;
+ if (reg & IDR5_GRAN4K)
+ smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
+
+ /* Input address size */
+ if (FIELD_GET(IDR5_VAX, reg) == IDR5_VAX_52_BIT)
+ smmu->features |= ARM_SMMU_FEAT_VAX;
+
+ switch (FIELD_GET(IDR5_OAS, reg)) {
+ case IDR5_OAS_32_BIT:
+ smmu->oas = 32;
+ break;
+ case IDR5_OAS_36_BIT:
+ smmu->oas = 36;
+ break;
+ case IDR5_OAS_40_BIT:
+ smmu->oas = 40;
+ break;
+ case IDR5_OAS_42_BIT:
+ smmu->oas = 42;
+ break;
+ case IDR5_OAS_44_BIT:
+ smmu->oas = 44;
+ break;
+ case IDR5_OAS_48_BIT:
+ smmu->oas = 48;
+ break;
+ case IDR5_OAS_52_BIT:
+ smmu->oas = 52;
+ smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
+ break;
+ }
+
+ return reg;
+}
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
new file mode 100644
index 000000000000..e736b6a8c78c
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __ARM_SMMU_V3_COMMON_LIB_H
+#define __ARM_SMMU_V3_COMMON_LIB_H
+
+#include <linux/build_bug.h>
+#include <linux/compiler_types.h>
+#include <linux/kernel.h>
+
+/*
+ * The IDR probe functions are used by the kernel and the
+ * hypervisor drivers where ARM_SMMU_OBJ might be defined
+ * differently.
+ * Ensure fields used by them are defined and has the correct
+ * types.
+ */
+#ifndef __KVM_NVHE_HYPERVISOR__
+typedef struct arm_smmu_device ARM_SMMU_OBJ;
+#endif
+
+static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, features), u32));
+static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, options), u32));
+static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, oas), unsigned long));
+static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, pgsize_bitmap), unsigned long));
+static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, base), void __iomem *));
+
+void arm_smmu_device_iidr_probe(ARM_SMMU_OBJ *smmu);
+u32 arm_smmu_idr0_probe(ARM_SMMU_OBJ *smmu);
+void arm_smmu_idr3_probe(ARM_SMMU_OBJ *smmu);
+u32 arm_smmu_idr5_probe(ARM_SMMU_OBJ *smmu);
+
+#endif /* __ARM_SMMU_V3_COMMON_LIB_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 2e54d1ba2566..c4c652431ee0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -33,6 +33,7 @@
#include <uapi/linux/iommufd.h>
#include "arm-smmu-v3.h"
+#include "arm-smmu-v3-common-lib.h"
#include "../../dma-iommu.h"
static bool disable_msipolling;
@@ -4907,54 +4908,6 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu)
return 0;
}
-#define IIDR_IMPLEMENTER_ARM 0x43b
-#define IIDR_PRODUCTID_ARM_MMU_600 0x483
-#define IIDR_PRODUCTID_ARM_MMU_700 0x487
-#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
-#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
-
-static void arm_smmu_device_iidr_probe(struct arm_smmu_device *smmu)
-{
- u32 reg;
- unsigned int implementer, productid, variant, revision;
-
- reg = readl_relaxed(smmu->base + ARM_SMMU_IIDR);
- implementer = FIELD_GET(IIDR_IMPLEMENTER, reg);
- productid = FIELD_GET(IIDR_PRODUCTID, reg);
- variant = FIELD_GET(IIDR_VARIANT, reg);
- revision = FIELD_GET(IIDR_REVISION, reg);
-
- switch (implementer) {
- case IIDR_IMPLEMENTER_ARM:
- switch (productid) {
- case IIDR_PRODUCTID_ARM_MMU_600:
- /* Arm erratum 1076982 */
- if (variant == 0 && revision <= 2)
- smmu->features &= ~ARM_SMMU_FEAT_SEV;
- /* Arm erratum 1209401 */
- if (variant < 2)
- smmu->features &= ~ARM_SMMU_FEAT_NESTING;
- break;
- case IIDR_PRODUCTID_ARM_MMU_700:
- /* Many errata... */
- smmu->features &= ~ARM_SMMU_FEAT_BTM;
- if (variant < 1 || revision < 1) {
- /* Arm erratum 2812531 */
- smmu->options |= ARM_SMMU_OPT_CMDQ_FORCE_SYNC;
- /* Arm errata 2268618, 2812531 */
- smmu->features &= ~ARM_SMMU_FEAT_NESTING;
- }
- break;
- case IIDR_PRODUCTID_ARM_MMU_L1:
- case IIDR_PRODUCTID_ARM_MMU_S3:
- /* Arm errata 3878312/3995052 */
- smmu->features &= ~ARM_SMMU_FEAT_BTM;
- break;
- }
- break;
- }
-}
-
static void arm_smmu_get_httu(struct arm_smmu_device *smmu, u32 reg)
{
u32 fw_features = smmu->features & (ARM_SMMU_FEAT_HA | ARM_SMMU_FEAT_HD |
@@ -4987,59 +4940,18 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
bool coherent = smmu->features & ARM_SMMU_FEAT_COHERENCY;
/* IDR0 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR0);
-
- /* 2-level structures */
- if (FIELD_GET(IDR0_ST_LVL, reg) == IDR0_ST_LVL_2LVL)
- smmu->features |= ARM_SMMU_FEAT_2_LVL_STRTAB;
-
- if (reg & IDR0_CD2L)
- smmu->features |= ARM_SMMU_FEAT_2_LVL_CDTAB;
-
- /*
- * Translation table endianness.
- * We currently require the same endianness as the CPU, but this
- * could be changed later by adding a new IO_PGTABLE_QUIRK.
- */
- switch (FIELD_GET(IDR0_TTENDIAN, reg)) {
- case IDR0_TTENDIAN_MIXED:
- smmu->features |= ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE;
- break;
-#ifdef __BIG_ENDIAN
- case IDR0_TTENDIAN_BE:
- smmu->features |= ARM_SMMU_FEAT_TT_BE;
- break;
-#else
- case IDR0_TTENDIAN_LE:
- smmu->features |= ARM_SMMU_FEAT_TT_LE;
- break;
-#endif
- default:
+ reg = arm_smmu_idr0_probe(smmu);
+ if (!(smmu->features & (ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE))) {
dev_err(smmu->dev, "unknown/unsupported TT endianness!\n");
return -ENXIO;
}
+ if (coherent && !disable_msipolling &&
+ smmu->features & ARM_SMMU_FEAT_MSI)
+ smmu->options |= ARM_SMMU_OPT_MSIPOLL;
- /* Boolean feature flags */
- if (IS_ENABLED(CONFIG_PCI_PRI) && reg & IDR0_PRI)
- smmu->features |= ARM_SMMU_FEAT_PRI;
-
- if (IS_ENABLED(CONFIG_PCI_ATS) && reg & IDR0_ATS)
- smmu->features |= ARM_SMMU_FEAT_ATS;
-
- if (reg & IDR0_SEV)
- smmu->features |= ARM_SMMU_FEAT_SEV;
-
- if (reg & IDR0_MSI) {
- smmu->features |= ARM_SMMU_FEAT_MSI;
- if (coherent && !disable_msipolling)
- smmu->options |= ARM_SMMU_OPT_MSIPOLL;
- }
-
- if (reg & IDR0_HYP) {
- smmu->features |= ARM_SMMU_FEAT_HYP;
- if (cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
- smmu->features |= ARM_SMMU_FEAT_E2H;
- }
+ if (smmu->features & ARM_SMMU_FEAT_HYP &&
+ cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
+ smmu->features |= ARM_SMMU_FEAT_E2H;
arm_smmu_get_httu(smmu, reg);
@@ -5051,21 +4963,7 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
dev_warn(smmu->dev, "IDR0.COHACC overridden by FW configuration (%s)\n",
str_true_false(coherent));
- switch (FIELD_GET(IDR0_STALL_MODEL, reg)) {
- case IDR0_STALL_MODEL_FORCE:
- smmu->features |= ARM_SMMU_FEAT_STALL_FORCE;
- fallthrough;
- case IDR0_STALL_MODEL_STALL:
- smmu->features |= ARM_SMMU_FEAT_STALLS;
- }
-
- if (reg & IDR0_S1P)
- smmu->features |= ARM_SMMU_FEAT_TRANS_S1;
-
- if (reg & IDR0_S2P)
- smmu->features |= ARM_SMMU_FEAT_TRANS_S2;
-
- if (!(reg & (IDR0_S1P | IDR0_S2P))) {
+ if (!(smmu->features & (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2))) {
dev_err(smmu->dev, "no translation support!\n");
return -ENXIO;
}
@@ -5123,62 +5021,17 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
/* IDR3 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR3);
- if (FIELD_GET(IDR3_RIL, reg))
- smmu->features |= ARM_SMMU_FEAT_RANGE_INV;
- if (FIELD_GET(IDR3_FWB, reg))
- smmu->features |= ARM_SMMU_FEAT_S2FWB;
-
- if (FIELD_GET(IDR3_BBM, reg) == 2)
- smmu->features |= ARM_SMMU_FEAT_BBML2;
+ arm_smmu_idr3_probe(smmu);
/* IDR5 */
- reg = readl_relaxed(smmu->base + ARM_SMMU_IDR5);
+ reg = arm_smmu_idr5_probe(smmu);
/* Maximum number of outstanding stalls */
smmu->evtq.max_stalls = FIELD_GET(IDR5_STALL_MAX, reg);
- if (reg & IDR5_DS)
- smmu->features |= ARM_SMMU_FEAT_DS;
-
- /* Page sizes */
- if (reg & IDR5_GRAN64K)
- smmu->pgsize_bitmap |= SZ_64K | SZ_512M;
- if (reg & IDR5_GRAN16K)
- smmu->pgsize_bitmap |= SZ_16K | SZ_32M;
- if (reg & IDR5_GRAN4K)
- smmu->pgsize_bitmap |= SZ_4K | SZ_2M | SZ_1G;
-
- /* Input address size */
- if (FIELD_GET(IDR5_VAX, reg) == IDR5_VAX_52_BIT)
- smmu->features |= ARM_SMMU_FEAT_VAX;
-
- /* Output address size */
- switch (FIELD_GET(IDR5_OAS, reg)) {
- case IDR5_OAS_32_BIT:
- smmu->oas = 32;
- break;
- case IDR5_OAS_36_BIT:
- smmu->oas = 36;
- break;
- case IDR5_OAS_40_BIT:
- smmu->oas = 40;
- break;
- case IDR5_OAS_42_BIT:
- smmu->oas = 42;
- break;
- case IDR5_OAS_44_BIT:
- smmu->oas = 44;
- break;
- case IDR5_OAS_52_BIT:
- smmu->oas = 52;
- smmu->pgsize_bitmap |= 1ULL << 42; /* 4TB */
- break;
- default:
+ if (!smmu->oas) {
dev_info(smmu->dev,
- "unknown output address size. Truncating to 48-bit\n");
- fallthrough;
- case IDR5_OAS_48_BIT:
+ "unknown output address size. Truncating to 48-bit\n");
smmu->oas = 48;
}
@@ -5187,10 +5040,6 @@ static int arm_smmu_device_hw_probe(struct arm_smmu_device *smmu)
dev_warn(smmu->dev,
"failed to set DMA mask for table walker\n");
- if ((smmu->features & ARM_SMMU_FEAT_TRANS_S1) &&
- (smmu->features & ARM_SMMU_FEAT_TRANS_S2))
- smmu->features |= ARM_SMMU_FEAT_NESTING;
-
arm_smmu_device_iidr_probe(smmu);
if (arm_smmu_sva_supported(smmu))
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index f3e80d103ba1..d5963a01452f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -86,6 +86,12 @@ struct arm_vsmmu;
#define IIDR_REVISION GENMASK(15, 12)
#define IIDR_IMPLEMENTER GENMASK(11, 0)
+#define IIDR_IMPLEMENTER_ARM 0x43b
+#define IIDR_PRODUCTID_ARM_MMU_600 0x483
+#define IIDR_PRODUCTID_ARM_MMU_700 0x487
+#define IIDR_PRODUCTID_ARM_MMU_L1 0x48a
+#define IIDR_PRODUCTID_ARM_MMU_S3 0x498
+
#define ARM_SMMU_AIDR 0x1C
#define ARM_SMMU_CR0 0x20
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* Re: [PATCH v8 04/25] iommu/arm-smmu-v3: Move IDR parsing to common functions
2026-09-22 13:12 ` [PATCH v8 04/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
@ 2026-09-22 19:45 ` Nicolin Chen
0 siblings, 0 replies; 31+ messages in thread
From: Nicolin Chen @ 2026-09-22 19:45 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jgg, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf, Jason Gunthorpe
On Tue, Sep 22, 2026 at 01:12:37PM +0000, Mostafa Saleh wrote:
> Move parsing of IDRs to functions so that it can be re-used
> from the hypervisor.
>
> As the new functions operate on structs from both the hypervisor
> and the kernel which would be different, we rely on the compilation
> unit to having ARM_SMMU_OBJ point to the correct struct; some
s/to having/to have
> best-effort static asserts were added .
s/added \./added\.
> +#ifndef __ARM_SMMU_V3_COMMON_LIB_H
> +#define __ARM_SMMU_V3_COMMON_LIB_H
> +
> +#include <linux/build_bug.h>
> +#include <linux/compiler_types.h>
> +#include <linux/kernel.h>
> +
> +/*
> + * The IDR probe functions are used by the kernel and the
> + * hypervisor drivers where ARM_SMMU_OBJ might be defined
> + * differently.
> + * Ensure fields used by them are defined and has the correct
> + * types.
s/has/have
We have 80 cols per line to write comments :)
> + */
> +#ifndef __KVM_NVHE_HYPERVISOR__
> +typedef struct arm_smmu_device ARM_SMMU_OBJ;
> +#endif
It's probably safer to include arm-smmu-v3.h so everything would
be self-defined.
Also, Jason's suggestion in v7 was hyp_arm_smmu_v3_device, which
looks nicer than ARM_SMMU_OBJ...
> +static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, features), u32));
> +static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, options), u32));
> +static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, oas), unsigned long));
> +static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, pgsize_bitmap), unsigned long));
> +static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, base), void __iomem *));
> +
> +void arm_smmu_device_iidr_probe(ARM_SMMU_OBJ *smmu);
> +u32 arm_smmu_idr0_probe(ARM_SMMU_OBJ *smmu);
> +void arm_smmu_idr3_probe(ARM_SMMU_OBJ *smmu);
> +u32 arm_smmu_idr5_probe(ARM_SMMU_OBJ *smmu);
Can we use "arm_smmu_device_xyz_probe" matching with the existing
arm_smmu_device_iidr_probe?
> + if (coherent && !disable_msipolling &&
> + smmu->features & ARM_SMMU_FEAT_MSI)
> + smmu->options |= ARM_SMMU_OPT_MSIPOLL;
Will pKVM ever use MSIPOLL?
> + if (smmu->features & ARM_SMMU_FEAT_HYP &&
> + cpus_have_cap(ARM64_HAS_VIRT_HOST_EXTN))
> + smmu->features |= ARM_SMMU_FEAT_E2H;
Why is ARM64_HAS_VIRT_HOST_EXTN left behind?
> - if (!(reg & (IDR0_S1P | IDR0_S2P))) {
> + if (!(smmu->features & (ARM_SMMU_FEAT_TRANS_S1 | ARM_SMMU_FEAT_TRANS_S2))) {
> dev_err(smmu->dev, "no translation support!\n");
> return -ENXIO;
This change seems unnecessary. The code above and below this line
still uses "reg" returned by idr0_probe(). So, the original code
should have read well:
if (!!(reg & IDR0_COHACC) != coherent)
dev_warn(smmu->dev, "IDR0.COHACC overridden by FW configuration (%s)\n",
str_true_false(coherent));
if (!(reg & (IDR0_S1P | IDR0_S2P))) {
dev_err(smmu->dev, "no translation support!\n");
return -ENXIO;
}
/* We only support the AArch64 table format at present */
if (!(FIELD_GET(IDR0_TTF, reg) & IDR0_TTF_AARCH64)) {
dev_err(smmu->dev, "AArch64 table format not supported!\n");
return -ENXIO;
}
Nicolin
^ permalink raw reply [flat|nested] 31+ messages in thread
* [PATCH v8 05/25] iommu/arm-smmu-v3: Move hitless machinery to common code
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (3 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 04/25] iommu/arm-smmu-v3: Move IDR parsing to common functions Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 19:59 ` Nicolin Chen
2026-09-22 13:12 ` [PATCH v8 06/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure Mostafa Saleh
` (20 subsequent siblings)
25 siblings, 1 reply; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Move the hitless STE functions to the common file so it can be
reused by the hypervisor.
No functional change.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.c | 240 +++++++++++++++++
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.h | 6 +
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c | 1 +
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 242 ------------------
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 7 +-
5 files changed, 249 insertions(+), 247 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
index a341974e7aaf..39b3cde9f5d2 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.c
@@ -4,6 +4,8 @@
* Arm SMMUv3 driver functions shared with hypervisor.
*/
+#include <kunit/visibility.h>
+
#include "arm-smmu-v3.h"
#include "arm-smmu-v3-common-lib.h"
@@ -174,3 +176,241 @@ u32 arm_smmu_idr5_probe(ARM_SMMU_OBJ *smmu)
return reg;
}
+
+void arm_smmu_get_ste_used(const __le64 *ent, __le64 *used_bits)
+{
+ unsigned int cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(ent[0]));
+
+ used_bits[0] = cpu_to_le64(STRTAB_STE_0_V);
+ if (!(ent[0] & cpu_to_le64(STRTAB_STE_0_V)))
+ return;
+
+ used_bits[0] |= cpu_to_le64(STRTAB_STE_0_CFG);
+
+ /* S1 translates */
+ if (cfg & BIT(0)) {
+ used_bits[0] |= cpu_to_le64(STRTAB_STE_0_S1FMT |
+ STRTAB_STE_0_S1CTXPTR_MASK |
+ STRTAB_STE_0_S1CDMAX);
+ used_bits[1] |=
+ cpu_to_le64(STRTAB_STE_1_S1DSS | STRTAB_STE_1_S1CIR |
+ STRTAB_STE_1_S1COR | STRTAB_STE_1_S1CSH |
+ STRTAB_STE_1_S1STALLD | STRTAB_STE_1_STRW |
+ STRTAB_STE_1_EATS | STRTAB_STE_1_MEV);
+ used_bits[2] |= cpu_to_le64(STRTAB_STE_2_S2VMID);
+
+ /*
+ * See 13.5 Summary of attribute/permission configuration fields
+ * for the SHCFG behavior.
+ */
+ if (FIELD_GET(STRTAB_STE_1_S1DSS, le64_to_cpu(ent[1])) ==
+ STRTAB_STE_1_S1DSS_BYPASS)
+ used_bits[1] |= cpu_to_le64(STRTAB_STE_1_SHCFG);
+ }
+
+ /* S2 translates */
+ if (cfg & BIT(1)) {
+ used_bits[1] |=
+ cpu_to_le64(STRTAB_STE_1_S2FWB | STRTAB_STE_1_EATS |
+ STRTAB_STE_1_SHCFG | STRTAB_STE_1_MEV);
+ used_bits[2] |=
+ cpu_to_le64(STRTAB_STE_2_S2VMID | STRTAB_STE_2_VTCR |
+ STRTAB_STE_2_S2AA64 | STRTAB_STE_2_S2ENDI |
+ STRTAB_STE_2_S2PTW | STRTAB_STE_2_S2S |
+ STRTAB_STE_2_S2R);
+ used_bits[3] |= cpu_to_le64(STRTAB_STE_3_S2TTB_MASK);
+ }
+
+ if (cfg == STRTAB_STE_0_CFG_BYPASS)
+ used_bits[1] |= cpu_to_le64(STRTAB_STE_1_SHCFG);
+}
+EXPORT_SYMBOL_IF_KUNIT(arm_smmu_get_ste_used);
+
+void arm_smmu_get_ste_update_safe(const __le64 *cur, const __le64 *target,
+ __le64 *safe_bits)
+{
+ const u64 eats_s1chk =
+ FIELD_PREP(STRTAB_STE_1_EATS, STRTAB_STE_1_EATS_S1CHK);
+ const u64 eats_trans =
+ FIELD_PREP(STRTAB_STE_1_EATS, STRTAB_STE_1_EATS_TRANS);
+
+ /*
+ * When an STE changes EATS_TRANS, the sequencing code in the attach
+ * logic already will have the PCI cap for ATS disabled. Thus at this
+ * moment we can expect that the device will not generate ATS queries
+ * and so we don't care about the sequencing of EATS. The purpose of
+ * EATS_TRANS is to protect the system from hostile untrusted devices
+ * that issue ATS when the PCI config space is disabled. However, if
+ * EATS_TRANS is being changed, then we must have already trusted the
+ * device as the EATS_TRANS security block is being disabled.
+ *
+ * Note: now the EATS_TRANS update is moved to the first entry_set().
+ * Changing S2S and EATS might transiently result in S2S=1 and EATS=1
+ * which is a bad STE (see "5.2 Stream Table Entry"). In such a case,
+ * we can't do a hitless update. Also, it should not be added to the
+ * safe bits with STRTAB_STE_1_EATS_S1CHK, because EATS=0b11 would be
+ * effectively an errant 0b00 configuration.
+ */
+ if (!((cur[1] | target[1]) & cpu_to_le64(eats_s1chk)) &&
+ !((cur[2] | target[2]) & cpu_to_le64(STRTAB_STE_2_S2S)))
+ safe_bits[1] |= cpu_to_le64(eats_trans);
+
+ /*
+ * MEV does not meaningfully impact the operation of the HW, it only
+ * changes how many fault events are generated, thus we can relax it
+ * when computing the ordering. The spec notes the device can act like
+ * MEV=1 anyhow:
+ *
+ * Note: Software must expect, and be able to deal with, coalesced
+ * fault records even when MEV == 0.
+ */
+ safe_bits[1] |= cpu_to_le64(STRTAB_STE_1_MEV);
+}
+EXPORT_SYMBOL_IF_KUNIT(arm_smmu_get_ste_update_safe);
+
+/*
+ * Figure out if we can do a hitless update of entry to become target. Returns a
+ * bit mask where 1 indicates that qword needs to be set disruptively.
+ * unused_update is an intermediate value of entry that has unused bits set to
+ * their new values.
+ */
+static u8 arm_smmu_entry_qword_diff(struct arm_smmu_entry_writer *writer,
+ const __le64 *entry, const __le64 *target,
+ __le64 *unused_update)
+{
+ __le64 target_used[NUM_ENTRY_QWORDS] = {};
+ __le64 cur_used[NUM_ENTRY_QWORDS] = {};
+ __le64 safe[NUM_ENTRY_QWORDS] = {};
+ u8 used_qword_diff = 0;
+ unsigned int i;
+
+ writer->ops->get_used(entry, cur_used);
+ writer->ops->get_used(target, target_used);
+ if (writer->ops->get_update_safe)
+ writer->ops->get_update_safe(entry, target, safe);
+
+ for (i = 0; i != NUM_ENTRY_QWORDS; i++) {
+ /*
+ * Safe is only used for bits that are used by both entries,
+ * otherwise it is sequenced according to the unused entry.
+ */
+ safe[i] &= target_used[i] & cur_used[i];
+
+ /*
+ * Check that masks are up to date, the make functions are not
+ * allowed to set a bit to 1 if the used function doesn't say it
+ * is used.
+ */
+ WARN_ON_ONCE(target[i] & ~target_used[i]);
+
+ /* Bits can change because they are not currently being used */
+ cur_used[i] &= ~safe[i];
+ unused_update[i] = (entry[i] & cur_used[i]) |
+ (target[i] & ~cur_used[i]);
+ /*
+ * Each bit indicates that a used bit in a qword needs to be
+ * changed after unused_update is applied.
+ */
+ if ((unused_update[i] & target_used[i]) != target[i])
+ used_qword_diff |= 1 << i;
+ }
+ return used_qword_diff;
+}
+
+static void entry_set(struct arm_smmu_entry_writer *writer, __le64 *entry,
+ const __le64 *target, unsigned int start,
+ unsigned int len)
+{
+ bool changed = false;
+ unsigned int i;
+
+ for (i = start; len != 0; len--, i++) {
+ if (entry[i] != target[i]) {
+ WRITE_ONCE(entry[i], target[i]);
+ changed = true;
+ }
+ }
+
+ if (changed)
+ writer->ops->sync(writer);
+}
+
+/*
+ * Update the STE/CD to the target configuration. The transition from the
+ * current entry to the target entry takes place over multiple steps that
+ * attempts to make the transition hitless if possible. This function takes care
+ * not to create a situation where the HW can perceive a corrupted entry. HW is
+ * only required to have a 64 bit atomicity with stores from the CPU, while
+ * entries are many 64 bit values big.
+ *
+ * The difference between the current value and the target value is analyzed to
+ * determine which of three updates are required - disruptive, hitless or no
+ * change.
+ *
+ * In the most general disruptive case we can make any update in three steps:
+ * - Disrupting the entry (V=0)
+ * - Fill now unused qwords, execpt qword 0 which contains V
+ * - Make qword 0 have the final value and valid (V=1) with a single 64
+ * bit store
+ *
+ * However this disrupts the HW while it is happening. There are several
+ * interesting cases where a STE/CD can be updated without disturbing the HW
+ * because only a small number of bits are changing (S1DSS, CONFIG, etc) or
+ * because the used bits don't intersect. We can detect this by calculating how
+ * many 64 bit values need update after adjusting the unused bits and skip the
+ * V=0 process. This relies on the IGNORED behavior described in the
+ * specification.
+ */
+void arm_smmu_write_entry(struct arm_smmu_entry_writer *writer, __le64 *entry,
+ const __le64 *target)
+{
+ __le64 unused_update[NUM_ENTRY_QWORDS];
+ u8 used_qword_diff;
+
+ /*
+ * Many of the entry structures have pointers to other structures that
+ * need to have their updates be visible before any writes of the entry
+ * happen.
+ */
+ dma_wmb();
+
+ used_qword_diff =
+ arm_smmu_entry_qword_diff(writer, entry, target, unused_update);
+ if (hweight8(used_qword_diff) == 1) {
+ /*
+ * Only one qword needs its used bits to be changed. This is a
+ * hitless update, update all bits the current STE/CD is
+ * ignoring to their new values, then update a single "critical
+ * qword" to change the STE/CD and finally 0 out any bits that
+ * are now unused in the target configuration.
+ */
+ unsigned int critical_qword_index = ffs(used_qword_diff) - 1;
+
+ /*
+ * Skip writing unused bits in the critical qword since we'll be
+ * writing it in the next step anyways. This can save a sync
+ * when the only change is in that qword.
+ */
+ unused_update[critical_qword_index] =
+ entry[critical_qword_index];
+ entry_set(writer, entry, unused_update, 0, NUM_ENTRY_QWORDS);
+ entry_set(writer, entry, target, critical_qword_index, 1);
+ entry_set(writer, entry, target, 0, NUM_ENTRY_QWORDS);
+ } else if (used_qword_diff) {
+ /*
+ * At least two qwords need their inuse bits to be changed. This
+ * requires a breaking update, zero the V bit, write all qwords
+ * but 0, then set qword 0
+ */
+ unused_update[0] = 0;
+ entry_set(writer, entry, unused_update, 0, 1);
+ entry_set(writer, entry, target, 1, NUM_ENTRY_QWORDS - 1);
+ entry_set(writer, entry, target, 0, 1);
+ } else {
+ /*
+ * No inuse bit changed, though safe bits may have changed.
+ */
+ entry_set(writer, entry, target, 0, NUM_ENTRY_QWORDS);
+ }
+}
+EXPORT_SYMBOL_IF_KUNIT(arm_smmu_write_entry);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
index e736b6a8c78c..9a7064c8e879 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
@@ -28,4 +28,10 @@ u32 arm_smmu_idr0_probe(ARM_SMMU_OBJ *smmu);
void arm_smmu_idr3_probe(ARM_SMMU_OBJ *smmu);
u32 arm_smmu_idr5_probe(ARM_SMMU_OBJ *smmu);
+void arm_smmu_get_ste_used(const __le64 *ent, __le64 *used_bits);
+void arm_smmu_get_ste_update_safe(const __le64 *cur, const __le64 *target,
+ __le64 *safe_bits);
+void arm_smmu_write_entry(struct arm_smmu_entry_writer *writer, __le64 *cur,
+ const __le64 *target);
+
#endif /* __ARM_SMMU_V3_COMMON_LIB_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
index add671363c82..ea9c85d2c7f0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-test.c
@@ -6,6 +6,7 @@
#include <linux/io-pgtable.h>
#include "arm-smmu-v3.h"
+#include "arm-smmu-v3-common-lib.h"
struct arm_smmu_test_writer {
struct arm_smmu_entry_writer writer;
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c4c652431ee0..2043c6dc1bdf 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -59,10 +59,8 @@ enum arm_smmu_msi_index {
ARM_SMMU_MAX_MSIS,
};
-#define NUM_ENTRY_QWORDS 8
static_assert(sizeof(struct arm_smmu_ste) == NUM_ENTRY_QWORDS * sizeof(u64));
static_assert(sizeof(struct arm_smmu_cd) == NUM_ENTRY_QWORDS * sizeof(u64));
-
static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
[EVTQ_MSI_INDEX] = {
ARM_SMMU_EVTQ_IRQ_CFG0,
@@ -1205,246 +1203,6 @@ EXPORT_SYMBOL_IF_KUNIT(arm_smmu_invs_purge);
* would be nice if this was complete according to the spec, but minimally it
* has to capture the bits this driver uses.
*/
-VISIBLE_IF_KUNIT
-void arm_smmu_get_ste_used(const __le64 *ent, __le64 *used_bits)
-{
- unsigned int cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(ent[0]));
-
- used_bits[0] = cpu_to_le64(STRTAB_STE_0_V);
- if (!(ent[0] & cpu_to_le64(STRTAB_STE_0_V)))
- return;
-
- used_bits[0] |= cpu_to_le64(STRTAB_STE_0_CFG);
-
- /* S1 translates */
- if (cfg & BIT(0)) {
- used_bits[0] |= cpu_to_le64(STRTAB_STE_0_S1FMT |
- STRTAB_STE_0_S1CTXPTR_MASK |
- STRTAB_STE_0_S1CDMAX);
- used_bits[1] |=
- cpu_to_le64(STRTAB_STE_1_S1DSS | STRTAB_STE_1_S1CIR |
- STRTAB_STE_1_S1COR | STRTAB_STE_1_S1CSH |
- STRTAB_STE_1_S1STALLD | STRTAB_STE_1_STRW |
- STRTAB_STE_1_EATS | STRTAB_STE_1_MEV);
- used_bits[2] |= cpu_to_le64(STRTAB_STE_2_S2VMID);
-
- /*
- * See 13.5 Summary of attribute/permission configuration fields
- * for the SHCFG behavior.
- */
- if (FIELD_GET(STRTAB_STE_1_S1DSS, le64_to_cpu(ent[1])) ==
- STRTAB_STE_1_S1DSS_BYPASS)
- used_bits[1] |= cpu_to_le64(STRTAB_STE_1_SHCFG);
- }
-
- /* S2 translates */
- if (cfg & BIT(1)) {
- used_bits[1] |=
- cpu_to_le64(STRTAB_STE_1_S2FWB | STRTAB_STE_1_EATS |
- STRTAB_STE_1_SHCFG | STRTAB_STE_1_MEV);
- used_bits[2] |=
- cpu_to_le64(STRTAB_STE_2_S2VMID | STRTAB_STE_2_VTCR |
- STRTAB_STE_2_S2AA64 | STRTAB_STE_2_S2ENDI |
- STRTAB_STE_2_S2PTW | STRTAB_STE_2_S2S |
- STRTAB_STE_2_S2R);
- used_bits[3] |= cpu_to_le64(STRTAB_STE_3_S2TTB_MASK);
- }
-
- if (cfg == STRTAB_STE_0_CFG_BYPASS)
- used_bits[1] |= cpu_to_le64(STRTAB_STE_1_SHCFG);
-}
-EXPORT_SYMBOL_IF_KUNIT(arm_smmu_get_ste_used);
-
-VISIBLE_IF_KUNIT
-void arm_smmu_get_ste_update_safe(const __le64 *cur, const __le64 *target,
- __le64 *safe_bits)
-{
- const u64 eats_s1chk =
- FIELD_PREP(STRTAB_STE_1_EATS, STRTAB_STE_1_EATS_S1CHK);
- const u64 eats_trans =
- FIELD_PREP(STRTAB_STE_1_EATS, STRTAB_STE_1_EATS_TRANS);
-
- /*
- * When an STE changes EATS_TRANS, the sequencing code in the attach
- * logic already will have the PCI cap for ATS disabled. Thus at this
- * moment we can expect that the device will not generate ATS queries
- * and so we don't care about the sequencing of EATS. The purpose of
- * EATS_TRANS is to protect the system from hostile untrusted devices
- * that issue ATS when the PCI config space is disabled. However, if
- * EATS_TRANS is being changed, then we must have already trusted the
- * device as the EATS_TRANS security block is being disabled.
- *
- * Note: now the EATS_TRANS update is moved to the first entry_set().
- * Changing S2S and EATS might transiently result in S2S=1 and EATS=1
- * which is a bad STE (see "5.2 Stream Table Entry"). In such a case,
- * we can't do a hitless update. Also, it should not be added to the
- * safe bits with STRTAB_STE_1_EATS_S1CHK, because EATS=0b11 would be
- * effectively an errant 0b00 configuration.
- */
- if (!((cur[1] | target[1]) & cpu_to_le64(eats_s1chk)) &&
- !((cur[2] | target[2]) & cpu_to_le64(STRTAB_STE_2_S2S)))
- safe_bits[1] |= cpu_to_le64(eats_trans);
-
- /*
- * MEV does not meaningfully impact the operation of the HW, it only
- * changes how many fault events are generated, thus we can relax it
- * when computing the ordering. The spec notes the device can act like
- * MEV=1 anyhow:
- *
- * Note: Software must expect, and be able to deal with, coalesced
- * fault records even when MEV == 0.
- */
- safe_bits[1] |= cpu_to_le64(STRTAB_STE_1_MEV);
-}
-EXPORT_SYMBOL_IF_KUNIT(arm_smmu_get_ste_update_safe);
-
-/*
- * Figure out if we can do a hitless update of entry to become target. Returns a
- * bit mask where 1 indicates that qword needs to be set disruptively.
- * unused_update is an intermediate value of entry that has unused bits set to
- * their new values.
- */
-static u8 arm_smmu_entry_qword_diff(struct arm_smmu_entry_writer *writer,
- const __le64 *entry, const __le64 *target,
- __le64 *unused_update)
-{
- __le64 target_used[NUM_ENTRY_QWORDS] = {};
- __le64 cur_used[NUM_ENTRY_QWORDS] = {};
- __le64 safe[NUM_ENTRY_QWORDS] = {};
- u8 used_qword_diff = 0;
- unsigned int i;
-
- writer->ops->get_used(entry, cur_used);
- writer->ops->get_used(target, target_used);
- if (writer->ops->get_update_safe)
- writer->ops->get_update_safe(entry, target, safe);
-
- for (i = 0; i != NUM_ENTRY_QWORDS; i++) {
- /*
- * Safe is only used for bits that are used by both entries,
- * otherwise it is sequenced according to the unused entry.
- */
- safe[i] &= target_used[i] & cur_used[i];
-
- /*
- * Check that masks are up to date, the make functions are not
- * allowed to set a bit to 1 if the used function doesn't say it
- * is used.
- */
- WARN_ON_ONCE(target[i] & ~target_used[i]);
-
- /* Bits can change because they are not currently being used */
- cur_used[i] &= ~safe[i];
- unused_update[i] = (entry[i] & cur_used[i]) |
- (target[i] & ~cur_used[i]);
- /*
- * Each bit indicates that a used bit in a qword needs to be
- * changed after unused_update is applied.
- */
- if ((unused_update[i] & target_used[i]) != target[i])
- used_qword_diff |= 1 << i;
- }
- return used_qword_diff;
-}
-
-static void entry_set(struct arm_smmu_entry_writer *writer, __le64 *entry,
- const __le64 *target, unsigned int start,
- unsigned int len)
-{
- bool changed = false;
- unsigned int i;
-
- for (i = start; len != 0; len--, i++) {
- if (entry[i] != target[i]) {
- WRITE_ONCE(entry[i], target[i]);
- changed = true;
- }
- }
-
- if (changed)
- writer->ops->sync(writer);
-}
-
-/*
- * Update the STE/CD to the target configuration. The transition from the
- * current entry to the target entry takes place over multiple steps that
- * attempts to make the transition hitless if possible. This function takes care
- * not to create a situation where the HW can perceive a corrupted entry. HW is
- * only required to have a 64 bit atomicity with stores from the CPU, while
- * entries are many 64 bit values big.
- *
- * The difference between the current value and the target value is analyzed to
- * determine which of three updates are required - disruptive, hitless or no
- * change.
- *
- * In the most general disruptive case we can make any update in three steps:
- * - Disrupting the entry (V=0)
- * - Fill now unused qwords, execpt qword 0 which contains V
- * - Make qword 0 have the final value and valid (V=1) with a single 64
- * bit store
- *
- * However this disrupts the HW while it is happening. There are several
- * interesting cases where a STE/CD can be updated without disturbing the HW
- * because only a small number of bits are changing (S1DSS, CONFIG, etc) or
- * because the used bits don't intersect. We can detect this by calculating how
- * many 64 bit values need update after adjusting the unused bits and skip the
- * V=0 process. This relies on the IGNORED behavior described in the
- * specification.
- */
-VISIBLE_IF_KUNIT
-void arm_smmu_write_entry(struct arm_smmu_entry_writer *writer, __le64 *entry,
- const __le64 *target)
-{
- __le64 unused_update[NUM_ENTRY_QWORDS];
- u8 used_qword_diff;
-
- /*
- * Many of the entry structures have pointers to other structures that
- * need to have their updates be visible before any writes of the entry
- * happen.
- */
- dma_wmb();
-
- used_qword_diff =
- arm_smmu_entry_qword_diff(writer, entry, target, unused_update);
- if (hweight8(used_qword_diff) == 1) {
- /*
- * Only one qword needs its used bits to be changed. This is a
- * hitless update, update all bits the current STE/CD is
- * ignoring to their new values, then update a single "critical
- * qword" to change the STE/CD and finally 0 out any bits that
- * are now unused in the target configuration.
- */
- unsigned int critical_qword_index = ffs(used_qword_diff) - 1;
-
- /*
- * Skip writing unused bits in the critical qword since we'll be
- * writing it in the next step anyways. This can save a sync
- * when the only change is in that qword.
- */
- unused_update[critical_qword_index] =
- entry[critical_qword_index];
- entry_set(writer, entry, unused_update, 0, NUM_ENTRY_QWORDS);
- entry_set(writer, entry, target, critical_qword_index, 1);
- entry_set(writer, entry, target, 0, NUM_ENTRY_QWORDS);
- } else if (used_qword_diff) {
- /*
- * At least two qwords need their inuse bits to be changed. This
- * requires a breaking update, zero the V bit, write all qwords
- * but 0, then set qword 0
- */
- unused_update[0] = 0;
- entry_set(writer, entry, unused_update, 0, 1);
- entry_set(writer, entry, target, 1, NUM_ENTRY_QWORDS - 1);
- entry_set(writer, entry, target, 0, 1);
- } else {
- /*
- * No inuse bit changed, though safe bits may have changed.
- */
- entry_set(writer, entry, target, 0, NUM_ENTRY_QWORDS);
- }
-}
-EXPORT_SYMBOL_IF_KUNIT(arm_smmu_write_entry);
static void arm_smmu_sync_cd(struct arm_smmu_master *master,
int ssid, bool leaf)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index d5963a01452f..28efa733e796 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1088,11 +1088,6 @@ void arm_smmu_make_s2_domain_ste(struct arm_smmu_ste *target,
bool ats_enabled);
#if IS_ENABLED(CONFIG_KUNIT)
-void arm_smmu_get_ste_used(const __le64 *ent, __le64 *used_bits);
-void arm_smmu_get_ste_update_safe(const __le64 *cur, const __le64 *target,
- __le64 *safe_bits);
-void arm_smmu_write_entry(struct arm_smmu_entry_writer *writer, __le64 *cur,
- const __le64 *target);
void arm_smmu_get_cd_used(const __le64 *ent, __le64 *used_bits);
void arm_smmu_make_bypass_ste(struct arm_smmu_device *smmu,
struct arm_smmu_ste *target);
@@ -1321,6 +1316,8 @@ static inline u64 arm_smmu_tlb_inv_range_enc(u8 num, u8 scale)
FIELD_PREP(CMDQ_TLBI_0_SCALE, scale & 0x1f);
}
+#define NUM_ENTRY_QWORDS 8
+
#ifdef CONFIG_ARM_SMMU_V3_SVA
bool arm_smmu_sva_supported(struct arm_smmu_device *smmu);
void arm_smmu_sva_notifier_synchronize(void);
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* Re: [PATCH v8 05/25] iommu/arm-smmu-v3: Move hitless machinery to common code
2026-09-22 13:12 ` [PATCH v8 05/25] iommu/arm-smmu-v3: Move hitless machinery to common code Mostafa Saleh
@ 2026-09-22 19:59 ` Nicolin Chen
0 siblings, 0 replies; 31+ messages in thread
From: Nicolin Chen @ 2026-09-22 19:59 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jgg, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Tue, Sep 22, 2026 at 01:12:38PM +0000, Mostafa Saleh wrote:
> Move the hitless STE functions to the common file so it can be
> reused by the hypervisor.
s/it/they
> No functional change.
>
> Signed-off-by: Mostafa Saleh <smostafa@google.com>
Reviewed-by: Nicolin Chen <nicolinc@nvidia.com>
With some nits:
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -59,10 +59,8 @@ enum arm_smmu_msi_index {
> ARM_SMMU_MAX_MSIS,
> };
>
> -#define NUM_ENTRY_QWORDS 8
> static_assert(sizeof(struct arm_smmu_ste) == NUM_ENTRY_QWORDS * sizeof(u64));
> static_assert(sizeof(struct arm_smmu_cd) == NUM_ENTRY_QWORDS * sizeof(u64));
> -
> static phys_addr_t arm_smmu_msi_cfg[ARM_SMMU_MAX_MSIS][3] = {
This line removal seems unnecessary.
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -1321,6 +1316,8 @@ static inline u64 arm_smmu_tlb_inv_range_enc(u8 num, u8 scale)
> FIELD_PREP(CMDQ_TLBI_0_SCALE, scale & 0x1f);
> }
>
> +#define NUM_ENTRY_QWORDS 8
> +
Maybe we should drop the duplicated define in arm-smmu-v3-test.c?
Nicolin
^ permalink raw reply [flat|nested] 31+ messages in thread
* [PATCH v8 06/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (4 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 05/25] iommu/arm-smmu-v3: Move hitless machinery to common code Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 07/25] KVM: arm64: iommu: Shadow host stage-2 page table Mostafa Saleh
` (19 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh,
Jean-Philippe Brucker
To establish DMA isolation, KVM needs an IOMMU driver which provides
ops implemented at EL2.
Only one driver can be used and is registered with
pkvm_iommu_register_driver() by passing pointer to the ops.
This must be called before module_init() which is the point KVM
initializes.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/include/asm/kvm_host.h | 5 +++++
arch/arm64/kvm/Makefile | 2 +-
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 11 +++++++++++
arch/arm64/kvm/hyp/nvhe/Makefile | 3 ++-
arch/arm64/kvm/hyp/nvhe/iommu.c | 19 +++++++++++++++++++
arch/arm64/kvm/hyp/nvhe/setup.c | 10 ++++++++++
arch/arm64/kvm/iommu.c | 25 +++++++++++++++++++++++++
7 files changed, 73 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/kvm/hyp/include/nvhe/iommu.h
create mode 100644 arch/arm64/kvm/hyp/nvhe/iommu.c
create mode 100644 arch/arm64/kvm/iommu.c
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 27fe0cd5b2d7..7ba7d384889e 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1717,4 +1717,9 @@ static __always_inline enum fgt_group_id __fgt_reg_to_group_id(enum vcpu_sysreg
long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext);
+#ifndef __KVM_NVHE_HYPERVISOR__
+struct pkvm_iommu_ops;
+int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops);
+#endif
+
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/Makefile b/arch/arm64/kvm/Makefile
index 59612d2f277c..0ddef54f7434 100644
--- a/arch/arm64/kvm/Makefile
+++ b/arch/arm64/kvm/Makefile
@@ -24,7 +24,7 @@ kvm-y += arm.o mmu.o mmio.o psci.o hypercalls.o pvtime.o \
vgic/vgic-mmio.o vgic/vgic-mmio-v2.o \
vgic/vgic-mmio-v3.o vgic/vgic-kvm-device.o \
vgic/vgic-its.o vgic/vgic-debug.o vgic/vgic-v3-nested.o \
- vgic/vgic-v5.o
+ vgic/vgic-v5.o iommu.o
kvm-$(CONFIG_HW_PERF_EVENTS) += pmu-emul.o pmu.o
kvm-$(CONFIG_ARM64_PTR_AUTH) += pauth.o
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
new file mode 100644
index 000000000000..83abe1a443c6
--- /dev/null
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ARM64_KVM_NVHE_IOMMU_H__
+#define __ARM64_KVM_NVHE_IOMMU_H__
+
+struct pkvm_iommu_ops {
+ int (*init)(void);
+};
+
+int pkvm_iommu_init(void);
+
+#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f57450ebcb49..7cb79db9bc47 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -24,7 +24,8 @@ CFLAGS_switch.nvhe.o += -Wno-override-init
hyp-obj-y := timer-sr.o sysreg-sr.o debug-sr.o switch.o tlb.o hyp-init.o host.o \
hyp-main.o hyp-smp.o psci-relay.o early_alloc.o page_alloc.o \
- cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o
+ cache.o setup.o mm.o mem_protect.o sys_regs.o pkvm.o stacktrace.o ffa.o \
+ iommu.o
hyp-obj-y += ../vgic-v3-sr.o ../aarch32.o ../vgic-v2-cpuif-proxy.o ../entry.o \
../hyp-entry.o ../exception.o ../pgtable.o ../vgic-v5-sr.o
hyp-obj-y += ../../../kernel/smccc-call.o
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu.c
new file mode 100644
index 000000000000..ef456eff42d2
--- /dev/null
+++ b/arch/arm64/kvm/hyp/nvhe/iommu.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOMMU operations for pKVM
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <nvhe/iommu.h>
+
+/* Only one set of ops supported */
+struct pkvm_iommu_ops *pkvm_iommu_ops;
+
+int pkvm_iommu_init(void)
+{
+ /* Keep DMA isolation optional. */
+ if (!pkvm_iommu_ops || !pkvm_iommu_ops->init)
+ return 0;
+
+ return pkvm_iommu_ops->init();
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 75b00c323310..9607d1b18a88 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -13,6 +13,7 @@
#include <nvhe/early_alloc.h>
#include <nvhe/ffa.h>
#include <nvhe/gfp.h>
+#include <nvhe/iommu.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
@@ -328,6 +329,15 @@ void __noreturn __pkvm_init_finalise(void)
if (ret)
goto out;
+ /*
+ * IOMMU init is done at the end, as it sets up and initializes many
+ * resources that would be leaked if the hypervisor fails after as there
+ * is no remove_iommu_driver() at the moment.
+ */
+ ret = pkvm_iommu_init();
+ if (ret)
+ goto out;
+
pkvm_hyp_vm_table_init(vm_table_base);
pkvm_ownership_selftest(selftest_base);
diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c
new file mode 100644
index 000000000000..30a3862e93d7
--- /dev/null
+++ b/arch/arm64/kvm/iommu.c
@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Google LLC
+ * Author: Mostafa Saleh <smostafa@google.com>
+ */
+
+#include <linux/kvm_host.h>
+
+extern struct pkvm_iommu_ops *kvm_nvhe_sym(pkvm_iommu_ops);
+
+static DEFINE_MUTEX(pkvm_iommu_reg_lock);
+
+int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops)
+{
+ guard(mutex)(&pkvm_iommu_reg_lock);
+
+ if (!is_protected_kvm_enabled() || is_kvm_arm_initialised())
+ return -EPERM;
+
+ if (kvm_nvhe_sym(pkvm_iommu_ops))
+ return -EBUSY;
+
+ kvm_nvhe_sym(pkvm_iommu_ops) = hyp_ops;
+ return 0;
+}
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 07/25] KVM: arm64: iommu: Shadow host stage-2 page table
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (5 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 06/25] KVM: arm64: iommu: Introduce IOMMU driver infrastructure Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 08/25] KVM: arm64: iommu: Add memory pool Mostafa Saleh
` (18 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Create a page-table for the IOMMU that shadows the host CPU stage-2
to establish DMA isolation.
An initial snapshot is created after the driver init, then
on every permission change a callback would be called for
the IOMMU driver to update the page table.
There are 3 different ways to add the callback:
1) In the high level memory transitions: (__pkvm_host_donate_hyp(),
__pkvm_host_donate_guest()...
2) In Lower level functions covering all transitions
- host_stage2_set_owner_metadata_locked() which covers:
- __pkvm_host_donate_hyp()
- __pkvm_host_donate_guest()
- __pkvm_host_donate_hyp()
- __pkvm_guest_unshare_host()
- host_stage2_set_owner_locked() only for ID_HOST which covers:
- __pkvm_hyp_donate_host()
- __pkvm_host_force_reclaim_page_guest()
- __pkvm_host_reclaim_page_guest()
- __pkvm_guest_share_host()
3) In the lowest level function __host_update_page_state(), which
requires only one callback. However, in that case the page state
is not enough as we might need to know the old state also.
Option #2 was implemented here.
For some cases, an SMMUv3 may be able to share the same page-table
used with the host CPU stage-2 directly.
However, this is too strict and requires changes to the core hypervisor
page-table code, plus it would require the hypervisor to handle IOMMU
page-faults. This can be added later as an optimization for SMMUV3.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 5 +
arch/arm64/kvm/hyp/nvhe/iommu.c | 130 +++++++++++++++++++++++-
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 27 ++---
3 files changed, 146 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 83abe1a443c6..2e35ec01c75d 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -2,10 +2,15 @@
#ifndef __ARM64_KVM_NVHE_IOMMU_H__
#define __ARM64_KVM_NVHE_IOMMU_H__
+#include <asm/kvm_pgtable.h>
+
struct pkvm_iommu_ops {
int (*init)(void);
+ int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
};
int pkvm_iommu_init(void);
+int pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
+ enum kvm_pgtable_prot prot);
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu.c
index ef456eff42d2..3637b0327d9e 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu.c
@@ -4,16 +4,138 @@
*
* Copyright (C) 2022 Linaro Ltd.
*/
+#include <linux/iommu.h>
+#include <asm/kvm_pkvm.h>
+
#include <nvhe/iommu.h>
+#include <nvhe/mem_protect.h>
+#include <nvhe/spinlock.h>
/* Only one set of ops supported */
struct pkvm_iommu_ops *pkvm_iommu_ops;
-int pkvm_iommu_init(void)
+/* Protected by host_mmu.lock */
+static bool pkvm_idmap_initialized;
+
+static inline int pkvm_to_iommu_prot(enum kvm_pgtable_prot prot)
{
- /* Keep DMA isolation optional. */
- if (!pkvm_iommu_ops || !pkvm_iommu_ops->init)
+ int iommu_prot = 0;
+
+ if (prot & KVM_PGTABLE_PROT_R)
+ iommu_prot |= IOMMU_READ;
+ if (prot & KVM_PGTABLE_PROT_W)
+ iommu_prot |= IOMMU_WRITE;
+
+ /* We don't understand that, might be dangerous. */
+ WARN_ON(prot & ~PKVM_HOST_MEM_PROT);
+ return iommu_prot;
+}
+
+/*
+ * IOMMU page tables are shadowed and not shared, that is mainly because:
+ * - Possible inconsistency between IOMMU and CPU features or format.
+ * - KVM relies on handling in page faults (BBM, lazy mapping).
+ */
+static int __snapshot_host_stage2(const struct kvm_pgtable_visit_ctx *ctx,
+ enum kvm_pgtable_walk_flags visit)
+{
+ bool is_memory = *(bool *)ctx->arg;
+ kvm_pte_t pte = *ctx->ptep;
+ u64 start = ctx->addr;
+ u64 block_end, end;
+ int prot;
+
+ block_end = ALIGN_DOWN(ctx->addr, kvm_granule_size(ctx->level)) +
+ kvm_granule_size(ctx->level);
+ end = min(ctx->end, block_end);
+ /*
+ * Keep annotated PTEs unmapped, and map everything else even lazily
+ * mapped PTEs (0), as the IOMMU can't handle page faults.
+ * That maps the whole address space which can be large, but that doesn't
+ * use a lot of memory as it will be mostly large blocks (1 GB with 4kb pages)
+ */
+ if (pte && !kvm_pte_valid(pte))
return 0;
- return pkvm_iommu_ops->init();
+ if (kvm_pte_valid(pte))
+ prot = pkvm_to_iommu_prot(kvm_pgtable_stage2_pte_prot(pte));
+ else
+ prot = IOMMU_READ | IOMMU_WRITE;
+
+ if (!is_memory)
+ prot |= IOMMU_MMIO;
+
+ return pkvm_iommu_ops->host_stage2_idmap(start, end, prot);
+}
+
+static int pkvm_iommu_snapshot_host_stage2(void)
+{
+ struct kvm_pgtable *pgt = &host_mmu.pgt;
+ bool is_memory;
+ struct kvm_pgtable_walker walker = {
+ .cb = __snapshot_host_stage2,
+ .flags = KVM_PGTABLE_WALK_LEAF,
+ .arg = &is_memory,
+ };
+ int ret = 0, i;
+ u64 start = 0;
+
+ hyp_spin_lock(&host_mmu.lock);
+ for (i = 0; i < hyp_memblock_nr; i++) {
+ struct memblock_region *reg = &hyp_memory[i];
+
+ if (start < reg->base) {
+ is_memory = false;
+ ret = kvm_pgtable_walk(pgt, start, reg->base - start, &walker);
+ if (ret)
+ goto out_unlock;
+ }
+
+ is_memory = true;
+ ret = kvm_pgtable_walk(pgt, reg->base, reg->size, &walker);
+ if (ret)
+ goto out_unlock;
+
+ start = reg->base + reg->size;
+ }
+
+ if (start < BIT(pgt->ia_bits)) {
+ is_memory = false;
+ ret = kvm_pgtable_walk(pgt, start, BIT(pgt->ia_bits) - start, &walker);
+ if (ret)
+ goto out_unlock;
+ }
+
+ pkvm_idmap_initialized = true;
+
+out_unlock:
+ hyp_spin_unlock(&host_mmu.lock);
+ return ret;
+}
+
+int pkvm_iommu_init(void)
+{
+ int ret;
+
+ /* Keep DMA isolation optional. */
+ if (!pkvm_iommu_ops || !pkvm_iommu_ops->init ||
+ !pkvm_iommu_ops->host_stage2_idmap)
+ return 0;
+
+ ret = pkvm_iommu_ops->init();
+ if (ret)
+ return ret;
+
+ return WARN_ON(pkvm_iommu_snapshot_host_stage2());
+}
+
+int pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
+ enum kvm_pgtable_prot prot)
+{
+ hyp_assert_lock_held(&host_mmu.lock);
+
+ if (!pkvm_idmap_initialized)
+ return 0;
+
+ return pkvm_iommu_ops->host_stage2_idmap(start, end, pkvm_to_iommu_prot(prot));
}
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index c1a8fd811c0f..da5014e4e96b 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -17,6 +17,7 @@
#include <nvhe/arm-smccc.h>
#include <nvhe/gfp.h>
+#include <nvhe/iommu.h>
#include <nvhe/memory.h>
#include <nvhe/mem_protect.h>
#include <nvhe/mm.h>
@@ -603,16 +604,15 @@ static int host_stage2_set_owner_metadata_locked(phys_addr_t addr, u64 size,
ret = host_stage2_try(kvm_pgtable_stage2_annotate, &host_mmu.pgt,
addr, size, &host_s2_pool,
KVM_HOST_INVALID_PTE_TYPE_DONATION, annotation);
- if (!ret) {
- /*
- * After stage2 maintenance has happened, but before the page
- * owner has changed.
- */
- pkvm_sme_dvmsync_fw_call();
- __host_update_page_state(addr, size, PKVM_NOPAGE);
- }
-
- return ret;
+ if (ret)
+ return ret;
+ /*
+ * After stage2 maintenance has happened, but before the page
+ * owner has changed.
+ */
+ pkvm_sme_dvmsync_fw_call();
+ __host_update_page_state(addr, size, PKVM_NOPAGE);
+ return WARN_ON(pkvm_iommu_host_stage2_idmap(addr, addr + size, 0));
}
int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
@@ -625,8 +625,10 @@ int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
return -EPERM;
ret = host_stage2_idmap_locked(addr, size, PKVM_HOST_MEM_PROT);
- if (!ret)
- __host_update_page_state(addr, size, PKVM_PAGE_OWNED);
+ if (ret)
+ break;
+ __host_update_page_state(addr, size, PKVM_PAGE_OWNED);
+ ret = WARN_ON(pkvm_iommu_host_stage2_idmap(addr, addr + size, PKVM_HOST_MEM_PROT));
break;
case PKVM_ID_HYP:
ret = host_stage2_set_owner_metadata_locked(addr, size,
@@ -1029,6 +1031,7 @@ int __pkvm_guest_share_host(struct pkvm_hyp_vcpu *vcpu, u64 gfn)
pkvm_mkstate(KVM_PGTABLE_PROT_RWX, PKVM_PAGE_SHARED_OWNED),
&vcpu->vcpu.arch.pkvm_memcache, 0));
WARN_ON(__host_set_page_state_range(phys, PAGE_SIZE, PKVM_PAGE_SHARED_BORROWED));
+ WARN_ON(pkvm_iommu_host_stage2_idmap(phys, phys + PAGE_SIZE, PKVM_HOST_MEM_PROT));
unlock:
guest_unlock_component(vm);
host_unlock_component();
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 08/25] KVM: arm64: iommu: Add memory pool
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (6 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 07/25] KVM: arm64: iommu: Shadow host stage-2 page table Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 09/25] KVM: arm64: iommu: Support DABT for IOMMU Mostafa Saleh
` (17 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
IOMMU drivers need to allocate memory for the shadow page table.
Similar to the host stage-2 CPU page table, the IOMMU pool
is allocated early from the carveout and its memory is added to
a pool which the IOMMU driver can allocate from and reclaim to at
run time.
As this is too early for drivers to use initcalls, the number of
pages allocated is set from command line "kvm-arm.iommu_pgt_mem".
Later when the driver registers, it will pass how many pages it
needs, and if it was more than what was allocated, it will fail
to register.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../admin-guide/kernel-parameters.txt | 5 +++
arch/arm64/include/asm/kvm_host.h | 3 +-
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 8 +++-
arch/arm64/kvm/hyp/nvhe/iommu.c | 21 +++++++++-
arch/arm64/kvm/hyp/nvhe/setup.c | 11 ++++-
arch/arm64/kvm/iommu.c | 41 ++++++++++++++++++-
arch/arm64/kvm/pkvm.c | 1 +
7 files changed, 85 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 33cd30996e47..408a1f431782 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3240,6 +3240,11 @@ Kernel parameters
max_snp_asid == min_sev_asid-1, will effectively make
SEV-ES unusable.
+ kvm-arm.iommu_pgt_mem=nn[KMG]
+ [KVM,ARM,EARLY]
+ Memory allocated for the IOMMU pool from the KVM carveout
+ when running in protected mode (See kvm-arm.mode=).
+
kvm-arm.mode=
[KVM,ARM,EARLY] Select one of KVM/arm64's modes of
operation.
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 7ba7d384889e..743d812e8ee0 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -1719,7 +1719,8 @@ long kvm_get_cap_for_kvm_ioctl(unsigned int ioctl, long *ext);
#ifndef __KVM_NVHE_HYPERVISOR__
struct pkvm_iommu_ops;
-int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops);
+int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops, unsigned int nr_pages);
+unsigned int pkvm_iommu_pages(void);
#endif
#endif /* __ARM64_KVM_HOST_H__ */
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 2e35ec01c75d..1fa728ab47d4 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -9,8 +9,14 @@ struct pkvm_iommu_ops {
int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
};
-int pkvm_iommu_init(void);
+int pkvm_iommu_init(void *pool_base, unsigned int nr_pages);
int pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
enum kvm_pgtable_prot prot);
+
+/* Allocate pages from the IOMMU carveout, returns zeroed memory. */
+void *pkvm_iommu_alloc_pages(u8 order);
+/* Free pages from pkvm_iommu_alloc_pages(). */
+void pkvm_iommu_free_pages(void *ptr);
+
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu.c
index 3637b0327d9e..cacab0dc462a 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu.c
@@ -16,6 +16,7 @@ struct pkvm_iommu_ops *pkvm_iommu_ops;
/* Protected by host_mmu.lock */
static bool pkvm_idmap_initialized;
+static struct hyp_pool iommu_pages_pool;
static inline int pkvm_to_iommu_prot(enum kvm_pgtable_prot prot)
{
@@ -113,7 +114,7 @@ static int pkvm_iommu_snapshot_host_stage2(void)
return ret;
}
-int pkvm_iommu_init(void)
+int pkvm_iommu_init(void *pool_base, unsigned int nr_pages)
{
int ret;
@@ -122,6 +123,14 @@ int pkvm_iommu_init(void)
!pkvm_iommu_ops->host_stage2_idmap)
return 0;
+ if (!nr_pages)
+ return -ENOMEM;
+
+ ret = hyp_pool_init(&iommu_pages_pool, hyp_virt_to_pfn(pool_base),
+ nr_pages, 0);
+ if (ret)
+ return ret;
+
ret = pkvm_iommu_ops->init();
if (ret)
return ret;
@@ -139,3 +148,13 @@ int pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
return pkvm_iommu_ops->host_stage2_idmap(start, end, pkvm_to_iommu_prot(prot));
}
+
+void *pkvm_iommu_alloc_pages(u8 order)
+{
+ return hyp_alloc_pages(&iommu_pages_pool, order);
+}
+
+void pkvm_iommu_free_pages(void *ptr)
+{
+ hyp_put_page(&iommu_pages_pool, ptr);
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/setup.c b/arch/arm64/kvm/hyp/nvhe/setup.c
index 9607d1b18a88..7ce1fc2232da 100644
--- a/arch/arm64/kvm/hyp/nvhe/setup.c
+++ b/arch/arm64/kvm/hyp/nvhe/setup.c
@@ -22,6 +22,8 @@
unsigned long hyp_nr_cpus;
+unsigned int hyp_kvm_iommu_pages;
+
#define hyp_percpu_size ((unsigned long)__per_cpu_end - \
(unsigned long)__per_cpu_start)
@@ -33,6 +35,7 @@ static void *selftest_base;
static void *ffa_proxy_pages;
static struct kvm_pgtable_mm_ops pkvm_pgtable_mm_ops;
static struct hyp_pool hpool;
+static void *iommu_base;
static int divide_memory_pool(void *virt, unsigned long size)
{
@@ -70,6 +73,12 @@ static int divide_memory_pool(void *virt, unsigned long size)
if (!ffa_proxy_pages)
return -ENOMEM;
+ if (hyp_kvm_iommu_pages) {
+ iommu_base = hyp_early_alloc_contig(hyp_kvm_iommu_pages);
+ if (!iommu_base)
+ return -ENOMEM;
+ }
+
return 0;
}
@@ -334,7 +343,7 @@ void __noreturn __pkvm_init_finalise(void)
* resources that would be leaked if the hypervisor fails after as there
* is no remove_iommu_driver() at the moment.
*/
- ret = pkvm_iommu_init();
+ ret = pkvm_iommu_init(iommu_base, hyp_kvm_iommu_pages);
if (ret)
goto out;
diff --git a/arch/arm64/kvm/iommu.c b/arch/arm64/kvm/iommu.c
index 30a3862e93d7..f008f68eee40 100644
--- a/arch/arm64/kvm/iommu.c
+++ b/arch/arm64/kvm/iommu.c
@@ -7,10 +7,11 @@
#include <linux/kvm_host.h>
extern struct pkvm_iommu_ops *kvm_nvhe_sym(pkvm_iommu_ops);
+extern unsigned int kvm_nvhe_sym(hyp_kvm_iommu_pages);
static DEFINE_MUTEX(pkvm_iommu_reg_lock);
-int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops)
+int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops, unsigned int nr_pages)
{
guard(mutex)(&pkvm_iommu_reg_lock);
@@ -20,6 +21,44 @@ int pkvm_iommu_register_driver(struct pkvm_iommu_ops *hyp_ops)
if (kvm_nvhe_sym(pkvm_iommu_ops))
return -EBUSY;
+ /* See pkvm_iommu_pages() */
+ if (nr_pages > kvm_nvhe_sym(hyp_kvm_iommu_pages)) {
+ kvm_err("IOMMU pool needs 0x%x pages, check kvm-arm.iommu_pgt_mem\n", nr_pages);
+ return -ENOMEM;
+ }
+
kvm_nvhe_sym(pkvm_iommu_ops) = hyp_ops;
return 0;
}
+
+unsigned int pkvm_iommu_pages(void)
+{
+ /*
+ * This is used very early during setup_arch() before any initcalls
+ * or any drivers are registered.
+ * This value is set by a command line option.
+ * Later, when the driver is registered, it will pass the number
+ * pages needed for it's page tables, if it was more than what
+ * the system has already allocated, it will fail registration.
+ */
+ return kvm_nvhe_sym(hyp_kvm_iommu_pages);
+}
+
+static int __init early_iommu_pgt_mem(char *arg)
+{
+ unsigned long long requested_size;
+
+ if (!arg)
+ return -EINVAL;
+
+ requested_size = memparse(arg, NULL);
+
+ if (requested_size > UINT_MAX) {
+ kvm_err("kvm-arm.iommu_pgt_mem is too large\n");
+ return -EINVAL;
+ }
+
+ kvm_nvhe_sym(hyp_kvm_iommu_pages) = DIV_ROUND_UP(requested_size, PAGE_SIZE);
+ return 0;
+}
+early_param("kvm-arm.iommu_pgt_mem", early_iommu_pgt_mem);
diff --git a/arch/arm64/kvm/pkvm.c b/arch/arm64/kvm/pkvm.c
index 8e4c6e4bec12..b6cf01e00f6b 100644
--- a/arch/arm64/kvm/pkvm.c
+++ b/arch/arm64/kvm/pkvm.c
@@ -63,6 +63,7 @@ void __init kvm_hyp_reserve(void)
hyp_mem_pages += hyp_vmemmap_pages(STRUCT_HYP_PAGE_SIZE);
hyp_mem_pages += pkvm_selftest_pages();
hyp_mem_pages += hyp_ffa_proxy_pages();
+ hyp_mem_pages += pkvm_iommu_pages();
/*
* Try to allocate a PMD-aligned region to reduce TLB pressure once
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 09/25] KVM: arm64: iommu: Support DABT for IOMMU
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (7 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 08/25] KVM: arm64: iommu: Add memory pool Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 10/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver Mostafa Saleh
` (16 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The pKVM SMMUv3 driver needs to trap and emulate access to the MMIO
space of the SMMUv3 to provide emulation for the kernel driver.
Add a handler for DABTs for IOMMU drivers to be able to do so.
In case the host causes a data abort, check if it's part of IOMMU
emulation first.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/include/nvhe/iommu.h | 2 ++
arch/arm64/kvm/hyp/nvhe/iommu.c | 14 ++++++++++++++
arch/arm64/kvm/hyp/nvhe/mem_protect.c | 15 +++++++++++++++
3 files changed, 31 insertions(+)
diff --git a/arch/arm64/kvm/hyp/include/nvhe/iommu.h b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
index 1fa728ab47d4..3f16879b5fa7 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/iommu.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/iommu.h
@@ -7,6 +7,7 @@
struct pkvm_iommu_ops {
int (*init)(void);
int (*host_stage2_idmap)(phys_addr_t start, phys_addr_t end, int prot);
+ bool (*dabt_handler)(struct user_pt_regs *regs, u64 esr, u64 addr);
};
int pkvm_iommu_init(void *pool_base, unsigned int nr_pages);
@@ -18,5 +19,6 @@ int pkvm_iommu_host_stage2_idmap(phys_addr_t start, phys_addr_t end,
void *pkvm_iommu_alloc_pages(u8 order);
/* Free pages from pkvm_iommu_alloc_pages(). */
void pkvm_iommu_free_pages(void *ptr);
+bool pkvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr);
#endif /* __ARM64_KVM_NVHE_IOMMU_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/iommu.c b/arch/arm64/kvm/hyp/nvhe/iommu.c
index cacab0dc462a..b7b11f6616cd 100644
--- a/arch/arm64/kvm/hyp/nvhe/iommu.c
+++ b/arch/arm64/kvm/hyp/nvhe/iommu.c
@@ -5,8 +5,11 @@
* Copyright (C) 2022 Linaro Ltd.
*/
#include <linux/iommu.h>
+#include <asm/kvm_hyp.h>
#include <asm/kvm_pkvm.h>
+#include <hyp/adjust_pc.h>
+
#include <nvhe/iommu.h>
#include <nvhe/mem_protect.h>
#include <nvhe/spinlock.h>
@@ -158,3 +161,14 @@ void pkvm_iommu_free_pages(void *ptr)
{
hyp_put_page(&iommu_pages_pool, ptr);
}
+
+bool pkvm_iommu_host_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
+{
+ if (pkvm_iommu_ops && pkvm_iommu_ops->dabt_handler &&
+ pkvm_iommu_ops->dabt_handler(regs, esr, addr)) {
+ /* DABT handled by the driver, skip to next instruction. */
+ kvm_skip_host_instr();
+ return true;
+ }
+ return false;
+}
diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
index da5014e4e96b..863c571e47e4 100644
--- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c
+++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c
@@ -758,6 +758,12 @@ static void host_inject_mem_abort(struct kvm_cpu_context *host_ctxt)
inject_host_exception(esr);
}
+static bool is_dabt_with_isv(u64 esr)
+{
+ return (ESR_ELx_EC(esr) == ESR_ELx_EC_DABT_LOW) &&
+ (esr & ESR_ELx_ISV);
+}
+
void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
{
struct kvm_vcpu_fault_info fault;
@@ -780,6 +786,15 @@ void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
BUG_ON(!(fault.hpfar_el2 & HPFAR_EL2_NS));
addr = FIELD_GET(HPFAR_EL2_FIPA, fault.hpfar_el2) << 12;
+ /*
+ * Emulate data aborts for IOMMU drivers, other access will be denied
+ * by host_stage2_adjust_range()
+ */
+ if (is_dabt_with_isv(esr) && !addr_is_memory(addr) &&
+ pkvm_iommu_host_dabt_handler(&host_ctxt->regs,
+ esr, addr | FAR_TO_FIPA_OFFSET(fault.far_el2)))
+ return;
+
switch (host_stage2_idmap(addr)) {
case -EPERM:
host_inject_mem_abort(host_ctxt);
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 10/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (8 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 09/25] KVM: arm64: iommu: Support DABT for IOMMU Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 11/25] iommu/arm-smmu-v3-kvm: Add the kernel driver Mostafa Saleh
` (15 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Jean-Philippe Brucker,
Mostafa Saleh
From: Jean-Philippe Brucker <jean-philippe@linaro.org>
Add the skeleton for an Arm SMMUv3 driver at EL2.
The driver rely on an array of SMMUv3s on the system, where at
init it will donate the array and the resources of the SMMUv3s
so they can't be changed by the host after de-privilege.
This array will be populated in the next patch.
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 5 +
drivers/iommu/arm/Kconfig | 12 +++
.../arm/arm-smmu-v3/arm-smmu-v3-common-lib.h | 4 +
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 31 +++++++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 91 +++++++++++++++++++
5 files changed, 143 insertions(+)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index 7cb79db9bc47..aa76c0f3f147 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -33,6 +33,11 @@ hyp-obj-$(CONFIG_LIST_HARDENED) += list_debug.o
hyp-obj-$(CONFIG_NVHE_EL2_TRACING) += clock.o trace.o events.o
hyp-obj-y += $(lib-objs)
+HYP_SMMU_V3_DRV_PATH = ../../../../../drivers/iommu/arm/arm-smmu-v3
+
+hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += $(HYP_SMMU_V3_DRV_PATH)/pkvm/arm-smmu-v3.o \
+ $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o ../../../../../lib/hweight.o
+
# Path to simple_ring_buffer.c
CFLAGS_trace.nvhe.o += -I$(srctree)/kernel/trace/
diff --git a/drivers/iommu/arm/Kconfig b/drivers/iommu/arm/Kconfig
index 5fac08b89dee..fdbed6a51224 100644
--- a/drivers/iommu/arm/Kconfig
+++ b/drivers/iommu/arm/Kconfig
@@ -141,3 +141,15 @@ config QCOM_IOMMU
select ARM_DMA_USE_IOMMU
help
Support for IOMMU on certain Qualcomm SoCs.
+
+config ARM_SMMU_V3_PKVM
+ bool "ARM SMMUv3 support for protected Virtual Machines"
+ depends on KVM && ARM_SMMU_V3=y
+ help
+ Enable a SMMUv3 driver in the KVM hypervisor, to protect VMs against
+ memory accesses from devices owned by the host.
+ This works along side ARM_SMMU_V3 where the kernel driver manages the
+ stage-1 of the SMMUv3, and the hypervisor driver will manage the
+ stage-2 transparently through trap and emulate.
+
+ Say Y here if you intend to enable KVM in protected mode.
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
index 9a7064c8e879..3a9d72988942 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-common-lib.h
@@ -15,6 +15,10 @@
*/
#ifndef __KVM_NVHE_HYPERVISOR__
typedef struct arm_smmu_device ARM_SMMU_OBJ;
+#else
+#include "pkvm/arm-smmu-v3-hyp.h"
+
+typedef struct hyp_arm_smmu_v3_device ARM_SMMU_OBJ;
#endif
static_assert(__same_type(typeof_member(ARM_SMMU_OBJ, features), u32));
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
new file mode 100644
index 000000000000..17b9454dab85
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __KVM_ARM_SMMU_V3_HYP_H
+#define __KVM_ARM_SMMU_V3_HYP_H
+
+#include <asm/kvm_asm.h>
+
+/*
+ * Parameters from the trusted host:
+ * @mmio_addr base address of the SMMU registers
+ * @mmio_size size of the registers resource
+ *
+ * Other members are filled and used at runtime by the SMMU driver.
+ * @base Virtual address of SMMU registers
+ */
+struct hyp_arm_smmu_v3_device {
+ phys_addr_t mmio_addr;
+ size_t mmio_size;
+ void __iomem *base;
+ u32 features;
+ u32 options;
+ unsigned long oas;
+ unsigned long pgsize_bitmap;
+};
+
+extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
+#define kvm_hyp_arm_smmu_v3_count kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count)
+
+extern struct hyp_arm_smmu_v3_device *kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus);
+#define kvm_hyp_arm_smmu_v3_smmus kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_smmus)
+
+#endif /* __KVM_ARM_SMMU_V3_HYP_H */
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
new file mode 100644
index 000000000000..7022d38e75c4
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pKVM hyp driver for the Arm SMMUv3
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <asm/kvm_hyp.h>
+
+#include <nvhe/iommu.h>
+#include <nvhe/mem_protect.h>
+
+#include "arm-smmu-v3-hyp.h"
+#include "../arm-smmu-v3.h"
+#include "../arm-smmu-v3-common-lib.h"
+
+size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
+struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
+
+#define for_each_smmu(smmu) \
+ for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
+ (smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
+ (smmu)++)
+
+/* Put the device in a state that can be probed by the host driver. */
+static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(__pkvm_hyp_donate_host_mmio(hyp_phys_to_pfn(smmu->mmio_addr),
+ smmu->mmio_size >> PAGE_SHIFT));
+ smmu->base = NULL;
+}
+
+static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
+{
+ unsigned long haddr;
+ int ret;
+
+ if (!PAGE_ALIGNED(smmu->mmio_addr | smmu->mmio_size))
+ return -EINVAL;
+
+ ret = __pkvm_host_donate_hyp_mmio(hyp_phys_to_pfn(smmu->mmio_addr),
+ smmu->mmio_size >> PAGE_SHIFT, &haddr);
+ if (ret)
+ return ret;
+
+ smmu->base = (void __iomem *)haddr;
+
+ return 0;
+}
+
+/* Called while is the host is still trusted. */
+static int smmu_init(void)
+{
+ size_t smmu_arr_size = PAGE_ALIGN(sizeof(*kvm_hyp_arm_smmu_v3_smmus) *
+ kvm_hyp_arm_smmu_v3_count);
+ struct hyp_arm_smmu_v3_device *smmu;
+ u64 pfn, nr_pages;
+ int ret;
+
+ kvm_hyp_arm_smmu_v3_smmus = kern_hyp_va(kvm_hyp_arm_smmu_v3_smmus);
+ pfn = hyp_virt_to_pfn(kvm_hyp_arm_smmu_v3_smmus);
+ nr_pages = smmu_arr_size >> PAGE_SHIFT;
+
+ ret = __pkvm_host_donate_hyp(pfn, nr_pages);
+ if (ret)
+ return ret;
+
+ for_each_smmu(smmu) {
+ ret = smmu_init_device(smmu);
+ if (ret)
+ goto out_reclaim_smmu;
+ }
+
+ return 0;
+
+out_reclaim_smmu:
+ while (smmu != kvm_hyp_arm_smmu_v3_smmus)
+ smmu_deinit_device(--smmu);
+ WARN_ON(__pkvm_hyp_donate_host(pfn, nr_pages));
+ return ret;
+}
+
+static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
+{
+ return 0;
+}
+
+/* Shared with the kernel driver in EL1 */
+struct pkvm_iommu_ops smmu_ops = {
+ .init = smmu_init,
+ .host_stage2_idmap = smmu_host_stage2_idmap,
+};
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 11/25] iommu/arm-smmu-v3-kvm: Add the kernel driver
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (9 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 10/25] iommu/arm-smmu-v3-kvm: Add SMMUv3 driver Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 12/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW Mostafa Saleh
` (14 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
When KVM runs in protected mode, and CONFIG_ARM_SMMU_V3_PKVM
is enabled, it will manage the SMMUv3 HW using trap and emulate
and present emulated SMMUs to the host kernel.
In that case, those SMMUs will be on the aux bus, so make it
possible to the driver to probe those devices.
Otherwise, everything else is the same, as the KVM emulation
complies with the architecture,so the driver doesn't need
to be modified.
Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/Makefile | 1 +
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 187 ++++++++++++++++++
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 67 +++++++
3 files changed, 255 insertions(+)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
diff --git a/drivers/iommu/arm/arm-smmu-v3/Makefile b/drivers/iommu/arm/arm-smmu-v3/Makefile
index c9ce392e6d31..c3fc5c4a4a1e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/Makefile
+++ b/drivers/iommu/arm/arm-smmu-v3/Makefile
@@ -4,5 +4,6 @@ arm_smmu_v3-y := arm-smmu-v3.o arm-smmu-v3-common-lib.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_IOMMUFD) += arm-smmu-v3-iommufd.o
arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_SVA) += arm-smmu-v3-sva.o
arm_smmu_v3-$(CONFIG_TEGRA241_CMDQV) += tegra241-cmdqv.o
+arm_smmu_v3-$(CONFIG_ARM_SMMU_V3_PKVM) += arm-smmu-v3-kvm.o
obj-$(CONFIG_ARM_SMMU_V3_KUNIT_TEST) += arm-smmu-v3-test.o
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
new file mode 100644
index 000000000000..9947d3a44304
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -0,0 +1,187 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pKVM host driver for the Arm SMMUv3
+ *
+ * Copyright (C) 2022 Linaro Ltd.
+ */
+#include <asm/kvm_mmu.h>
+#include <asm/kvm_pkvm.h>
+
+#include <linux/auxiliary_bus.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+
+#include "arm-smmu-v3.h"
+#include "pkvm/arm-smmu-v3-hyp.h"
+
+extern struct pkvm_iommu_ops kvm_nvhe_sym(smmu_ops);
+
+static size_t kvm_arm_smmu_count;
+static struct hyp_arm_smmu_v3_device *kvm_arm_smmu_array;
+static size_t kvm_arm_smmu_cur;
+
+static void kvm_arm_smmu_array_free(void)
+{
+ int order;
+
+ order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+ free_pages((unsigned long)kvm_arm_smmu_array, order);
+}
+
+static int kvm_arm_smmu_array_alloc(void)
+{
+ int smmu_order;
+ struct device_node *np;
+
+ for_each_compatible_node(np, NULL, "arm,smmu-v3")
+ kvm_arm_smmu_count++;
+
+ if (!kvm_arm_smmu_count)
+ return -ENODEV;
+ smmu_order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
+ kvm_arm_smmu_array = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, smmu_order);
+ if (!kvm_arm_smmu_array)
+ return -ENOMEM;
+ return 0;
+}
+
+static unsigned int smmu_hyp_pgt_pages(void)
+{
+ struct device_node *np = of_find_compatible_node(NULL, NULL, "arm,smmu-v3");
+
+ /*
+ * SMMUv3 uses the same format as the CPU stage-2 and hence have the same memory
+ * requirements, we add extra 500 pages for L2 STEs.
+ * Only one set of memory is allocated as the page table is shared between all
+ * the SMMUs.
+ */
+ if (np) {
+ of_node_put(np);
+ return host_s2_pgtable_pages() + 500;
+ }
+
+ return 0;
+}
+
+static struct platform_driver smmuv3_nesting_driver;
+static int smmuv3_nesting_probe(struct platform_device *pdev)
+{
+ struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+
+ /* Only device tree, ACPI not supported. */
+ if (!dev->of_node)
+ return -EINVAL;
+
+ if (kvm_arm_smmu_cur >= kvm_arm_smmu_count)
+ return -ENOSPC;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENODEV;
+
+ if (of_property_read_bool(dev->of_node, "cavium,cn9900-broken-page1-regspace"))
+ return -EINVAL;
+
+ smmu->mmio_addr = res->start;
+ smmu->mmio_size = resource_size(res);
+ if (smmu->mmio_size < SZ_128K) {
+ dev_err(dev, "MMIO region too small(%pr)\n", res);
+ return -EINVAL;
+ }
+
+ if (of_dma_is_coherent(dev->of_node))
+ smmu->features |= ARM_SMMU_FEAT_COHERENCY;
+
+ kvm_arm_smmu_cur++;
+ return 0;
+}
+
+static int __init kvm_arm_smmu_v3_register(void)
+{
+ size_t nr_pages = smmu_hyp_pgt_pages();
+ int ret;
+
+ if (!is_protected_kvm_enabled() || !nr_pages)
+ return 0;
+
+ ret = kvm_arm_smmu_array_alloc();
+ if (ret)
+ goto out_err;
+
+ ret = platform_driver_probe(&smmuv3_nesting_driver, smmuv3_nesting_probe);
+ if (ret)
+ goto out_free;
+
+ ret = pkvm_iommu_register_driver(kern_hyp_va(lm_alias(&kvm_nvhe_sym(smmu_ops))),
+ nr_pages);
+ if (ret)
+ goto out_unregister;
+
+ /*
+ * These variables are stored in the nVHE image, and won't be accessible
+ * after KVM initialization. Ownership of kvm_arm_smmu_array will be
+ * transferred to the hypervisor as well.
+ */
+ kvm_hyp_arm_smmu_v3_smmus = kvm_arm_smmu_array;
+ kvm_hyp_arm_smmu_v3_count = kvm_arm_smmu_cur;
+ return ret;
+
+out_unregister:
+ platform_driver_unregister(&smmuv3_nesting_driver);
+out_free:
+ kvm_arm_smmu_array_free();
+out_err:
+ kvm_arm_smmu_count = 0;
+ kvm_arm_smmu_array = NULL;
+ return ret;
+};
+
+static int smmu_create_aux_device(struct device *dev, void *data)
+{
+ static int dev_id;
+ struct auxiliary_device *auxdev;
+
+ auxdev = __devm_auxiliary_device_create(dev, "protected_kvm",
+ "smmu_v3_emu", NULL, dev_id++);
+ if (!auxdev)
+ return -ENODEV;
+ return 0;
+}
+
+static int kvm_arm_smmu_v3_post_init(void)
+{
+ if (!kvm_arm_smmu_count)
+ return 0;
+
+ /*
+ * If the hypervisor part of the driver fails, KVM will not initialise.
+ */
+ if (!is_kvm_arm_initialised()) {
+ kvm_arm_smmu_array_free();
+ platform_driver_unregister(&smmuv3_nesting_driver);
+ return 0;
+ }
+
+ WARN_ON(driver_for_each_device(&smmuv3_nesting_driver.driver, NULL,
+ NULL, smmu_create_aux_device));
+
+ return 0;
+}
+
+static const struct of_device_id smmuv3_nested_of_match[] = {
+ { .compatible = "arm,smmu-v3", },
+ { },
+};
+
+static struct platform_driver smmuv3_nesting_driver = {
+ .driver = {
+ .name = "smmuv3-nesting",
+ .of_match_table = smmuv3_nested_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+late_initcall(kvm_arm_smmu_v3_post_init);
+subsys_initcall(kvm_arm_smmu_v3_register);
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 2043c6dc1bdf..d6d1e2d30ef6 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -11,6 +11,7 @@
#include <linux/acpi.h>
#include <linux/acpi_iort.h>
+#include <linux/auxiliary_bus.h>
#include <linux/bitops.h>
#include <linux/crash_dump.h>
#include <linux/delay.h>
@@ -5203,6 +5204,72 @@ static struct platform_driver arm_smmu_driver = {
module_driver(arm_smmu_driver, platform_driver_register,
arm_smmu_driver_unregister);
+#ifdef CONFIG_ARM_SMMU_V3_PKVM
+/*
+ * Now we have 2 devices, the aux device bound to this driver, and pdev
+ * which is the physical platform device bound to the KVM driver but not used.
+ * However, this driver keeps using the platform device for 2 reasons:
+ * 1) Simplicity: Avoiding changing big parts of the code assuming
+ * the underlying device is a platform device.
+ * 2) Dealing with DMA-API, irqs(MSIs), RPM... requires the physical device.
+ *
+ * That means arm_smmu_device_probe() allocates its devm resources on the
+ * platform device, where they are not freed when the aux device unbinds.
+ * The devres group bounds them to the lifetime of this binding instead.
+ *
+ * The platform device is never unbound, as both drivers set
+ * suppress_bind_attrs and ARM_SMMU_V3_PKVM requires ARM_SMMU_V3=y.
+ */
+static int arm_smmu_device_probe_emu(struct auxiliary_device *auxdev,
+ const struct auxiliary_device_id *id)
+{
+ struct device *parent = auxdev->dev.parent;
+ void *group;
+ int ret;
+
+ dev_info(&auxdev->dev, "Probing from %s\n", dev_name(parent));
+ group = devres_open_group(parent, NULL, GFP_KERNEL);
+ if (!group)
+ return -ENOMEM;
+
+ ret = arm_smmu_device_probe(to_platform_device(parent));
+ if (ret)
+ devres_release_group(parent, group);
+ else
+ devres_close_group(parent, group);
+ return ret;
+}
+
+static void arm_smmu_device_remove_emu(struct auxiliary_device *auxdev)
+{
+ arm_smmu_device_remove(to_platform_device(auxdev->dev.parent));
+}
+
+static void arm_smmu_device_shutdown_emu(struct auxiliary_device *auxdev)
+{
+ arm_smmu_device_shutdown(to_platform_device(auxdev->dev.parent));
+}
+
+static const struct auxiliary_device_id arm_smmu_aux_table[] = {
+ { .name = "protected_kvm.smmu_v3_emu" },
+ { },
+};
+MODULE_DEVICE_TABLE(auxiliary, arm_smmu_aux_table);
+
+static struct auxiliary_driver arm_smmu_driver_emu = {
+ .driver = {
+ .suppress_bind_attrs = true,
+ },
+ .name = "arm-smmu-v3-emu",
+ .id_table = arm_smmu_aux_table,
+ .probe = arm_smmu_device_probe_emu,
+ .remove = arm_smmu_device_remove_emu,
+ .shutdown = arm_smmu_device_shutdown_emu,
+};
+
+module_auxiliary_driver(arm_smmu_driver_emu);
+#endif
+
MODULE_DESCRIPTION("IOMMU API for ARM architected SMMUv3 implementations");
MODULE_AUTHOR("Will Deacon <will@kernel.org>");
MODULE_ALIAS("platform:arm-smmu-v3");
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 12/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (10 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 11/25] iommu/arm-smmu-v3-kvm: Add the kernel driver Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 13/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation Mostafa Saleh
` (13 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Probe SMMU features from the IDR register space. Most of
the logic is common with the kernel.
The hypervisor enforces 2 extra requirements:
- Cache coherency.
- Nested translation support.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 4 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 47 +++++++++++++++++++
2 files changed, 51 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index 17b9454dab85..91177f00fa97 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -11,6 +11,9 @@
*
* Other members are filled and used at runtime by the SMMU driver.
* @base Virtual address of SMMU registers
+ * @oas PA size
+ * @pgsize_bitmap Supported page sizes
+ * @sid_bits Max number of SID bits supported
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -20,6 +23,7 @@ struct hyp_arm_smmu_v3_device {
u32 options;
unsigned long oas;
unsigned long pgsize_bitmap;
+ unsigned int sid_bits;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 7022d38e75c4..f8b7c5406017 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -29,6 +29,47 @@ static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
smmu->base = NULL;
}
+/*
+ * Mini-probe and validation for the hypervisor.
+ */
+static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u32 reg;
+
+ if (!(smmu->features & ARM_SMMU_FEAT_COHERENCY))
+ return -EINVAL;
+
+ reg = arm_smmu_idr0_probe(smmu);
+
+ if (!(FIELD_GET(IDR0_TTF, reg) & IDR0_TTF_AARCH64))
+ return -ENXIO;
+
+ if (!(smmu->features & (ARM_SMMU_FEAT_TT_LE | ARM_SMMU_FEAT_TT_BE)))
+ return -ENXIO;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
+ if (reg & (IDR1_TABLES_PRESET | IDR1_QUEUES_PRESET | IDR1_REL))
+ return -EINVAL;
+
+ smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+ /* Follows the kernel logic */
+ if (smmu->sid_bits <= STRTAB_SPLIT)
+ smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
+
+ arm_smmu_idr3_probe(smmu);
+
+ arm_smmu_idr5_probe(smmu);
+ if (!smmu->oas)
+ smmu->oas = 48;
+
+ arm_smmu_device_iidr_probe(smmu);
+
+ if (!(smmu->features & ARM_SMMU_FEAT_NESTING))
+ return -ENXIO;
+
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -43,8 +84,14 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
return ret;
smmu->base = (void __iomem *)haddr;
+ ret = smmu_probe(smmu);
+ if (ret)
+ goto out_ret;
return 0;
+out_ret:
+ smmu_deinit_device(smmu);
+ return ret;
}
/* Called while is the host is still trusted. */
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 13/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (11 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 12/25] iommu/arm-smmu-v3-kvm: Probe SMMU HW Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 14/25] iommu/arm-smmu-v3-kvm: Shadow the command queue Mostafa Saleh
` (12 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add data abort handler for the SMMUs, at the moment most registers
are just passthrough.
In the next patches CMDQ/STE emulation will be added which inserts
logic to some register access.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 14 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 159 ++++++++++++++++++
2 files changed, 173 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index 91177f00fa97..58fa14c239e3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -4,6 +4,10 @@
#include <asm/kvm_asm.h>
+#ifdef __KVM_NVHE_HYPERVISOR__
+#include <nvhe/spinlock.h>
+#endif
+
/*
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
@@ -14,6 +18,9 @@
* @oas PA size
* @pgsize_bitmap Supported page sizes
* @sid_bits Max number of SID bits supported
+ * @lock Lock to protect SMMU emulation
+ * @hw_lock Lock to protect SMMU HW (as CMDQ)
+ * Order smmu.lock => host_mmu.lock => smmu.hw_lock
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -24,6 +31,13 @@ struct hyp_arm_smmu_v3_device {
unsigned long oas;
unsigned long pgsize_bitmap;
unsigned int sid_bits;
+#ifdef __KVM_NVHE_HYPERVISOR__
+ hyp_spinlock_t lock;
+ hyp_spinlock_t hw_lock;
+#else
+ u32 lock;
+ u32 hw_lock;
+#endif
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index f8b7c5406017..7a51cb70205f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -8,6 +8,7 @@
#include <nvhe/iommu.h>
#include <nvhe/mem_protect.h>
+#include <nvhe/trap_handler.h>
#include "arm-smmu-v3-hyp.h"
#include "../arm-smmu-v3.h"
@@ -78,6 +79,9 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (!PAGE_ALIGNED(smmu->mmio_addr | smmu->mmio_size))
return -EINVAL;
+ hyp_spin_lock_init(&smmu->lock);
+ hyp_spin_lock_init(&smmu->hw_lock);
+
ret = __pkvm_host_donate_hyp_mmio(hyp_phys_to_pfn(smmu->mmio_addr),
smmu->mmio_size >> PAGE_SHIFT, &haddr);
if (ret)
@@ -117,6 +121,8 @@ static int smmu_init(void)
goto out_reclaim_smmu;
}
+ BUILD_BUG_ON(sizeof(hyp_spinlock_t) != sizeof(u32));
+
return 0;
out_reclaim_smmu:
@@ -126,6 +132,158 @@ static int smmu_init(void)
return ret;
}
+static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
+ struct user_pt_regs *regs,
+ u64 esr, u32 off)
+{
+ bool is_write = esr & ESR_ELx_WNR;
+ unsigned int len = BIT((esr & ESR_ELx_SAS) >> ESR_ELx_SAS_SHIFT);
+ int rd = (esr & ESR_ELx_SRT_MASK) >> ESR_ELx_SRT_SHIFT;
+ const u64 read_write = -1ULL;
+ const u64 no_access = 0;
+ u64 mask = no_access;
+ const u64 read_only = is_write ? no_access : read_write;
+ bool is_xzr = (rd == 31);
+ u64 val = is_xzr ? 0 : regs->regs[rd];
+
+ switch (off) {
+ case ARM_SMMU_IDR0:
+ if (len != sizeof(u32))
+ break;
+ /*
+ * Clear stage-2 support, hide MSI to avoid write back to cmdq,
+ * and hide ATS as it is not emulated or handled in TLB invalidation.
+ */
+ mask = read_only & ~(IDR0_S2P | IDR0_VMID16 | IDR0_MSI | IDR0_HYP | IDR0_ATS);
+ break;
+ /* Passthrough the register access for bisectability, handled later */
+ case ARM_SMMU_CMDQ_BASE:
+ case ARM_SMMU_CMDQ_PROD:
+ case ARM_SMMU_CMDQ_CONS:
+ case ARM_SMMU_STRTAB_BASE:
+ case ARM_SMMU_STRTAB_BASE_CFG:
+ case ARM_SMMU_GBPA:
+ mask = read_write;
+ break;
+ case ARM_SMMU_CR0:
+ if (len != sizeof(u32))
+ break;
+ mask = read_write;
+ break;
+ case ARM_SMMU_CR1:
+ if (len != sizeof(u32))
+ break;
+ /* Don't mess with shareability/cacheability. */
+ if (is_write &&
+ (val != (FIELD_PREP(CR1_TABLE_SH, ARM_SMMU_SH_ISH) |
+ FIELD_PREP(CR1_TABLE_OC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_TABLE_IC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_QUEUE_SH, ARM_SMMU_SH_ISH) |
+ FIELD_PREP(CR1_QUEUE_OC, CR1_CACHE_WB) |
+ FIELD_PREP(CR1_QUEUE_IC, CR1_CACHE_WB))))
+ break;
+
+ mask = read_write;
+ break;
+ /* Allowed 32 bit registers. */
+ case ARM_SMMU_EVTQ_IRQ_CFG1:
+ case ARM_SMMU_EVTQ_IRQ_CFG2:
+ case ARM_SMMU_GERROR_IRQ_CFG1:
+ case ARM_SMMU_GERROR_IRQ_CFG2:
+ case ARM_SMMU_PRIQ_IRQ_CFG1:
+ case ARM_SMMU_PRIQ_IRQ_CFG2:
+ /* These are RES0 as MSI support is hidden. */
+ val = 0;
+ if (!is_write)
+ goto out_update_regs;
+ fallthrough;
+ case ARM_SMMU_EVTQ_PROD + SZ_64K:
+ case ARM_SMMU_EVTQ_CONS + SZ_64K:
+ case ARM_SMMU_PRIQ_PROD + SZ_64K:
+ case ARM_SMMU_PRIQ_CONS + SZ_64K:
+ case ARM_SMMU_GERRORN:
+ case ARM_SMMU_IRQ_CTRLACK:
+ case ARM_SMMU_IRQ_CTRL:
+ case ARM_SMMU_CR0ACK:
+ case ARM_SMMU_CR2:
+ if (len != sizeof(u32))
+ break;
+ mask = read_write;
+ break;
+ /* Allowed 64 bit registers. */
+ case ARM_SMMU_EVTQ_IRQ_CFG0:
+ case ARM_SMMU_PRIQ_IRQ_CFG0:
+ case ARM_SMMU_GERROR_IRQ_CFG0:
+ /* These are RES0 as MSI support is hidden. */
+ val = 0;
+ if (!is_write)
+ goto out_update_regs;
+ fallthrough;
+ case ARM_SMMU_EVTQ_BASE:
+ case ARM_SMMU_PRIQ_BASE:
+ if (len != sizeof(u64))
+ break;
+ mask = read_write;
+ break;
+ /* Allowed RO 32 bit registers. */
+ case ARM_SMMU_IIDR:
+ case ARM_SMMU_IDR5:
+ case ARM_SMMU_IDR3:
+ case ARM_SMMU_IDR1:
+ case ARM_SMMU_GERROR:
+ if (len != sizeof(u32))
+ break;
+ mask = read_only;
+ break;
+ }
+
+ if (WARN_ON(!mask))
+ goto out_ret;
+
+ hyp_spin_lock(&smmu->hw_lock);
+ if (is_write) {
+ if (len == sizeof(u64))
+ writeq_relaxed(val & mask, smmu->base + off);
+ else
+ writel_relaxed(val & mask, smmu->base + off);
+
+ hyp_spin_unlock(&smmu->hw_lock);
+ return true;
+ }
+
+ if (len == sizeof(u64))
+ val = readq_relaxed(smmu->base + off) & mask;
+ else
+ val = readl_relaxed(smmu->base + off) & mask;
+ hyp_spin_unlock(&smmu->hw_lock);
+out_update_regs:
+ /*
+ * Device might be read sensitive, so do it but ignore writing
+ * back for xzr.
+ */
+ if (!is_xzr)
+ regs->regs[rd] = val;
+
+out_ret:
+ return true;
+}
+
+static bool smmu_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
+{
+ struct hyp_arm_smmu_v3_device *smmu;
+ bool ret;
+
+ for_each_smmu(smmu) {
+ if (addr < smmu->mmio_addr || addr >= smmu->mmio_addr + smmu->mmio_size)
+ continue;
+ hyp_spin_lock(&smmu->lock);
+ ret = smmu_dabt_device(smmu, regs, esr, addr - smmu->mmio_addr);
+ hyp_spin_unlock(&smmu->lock);
+ return ret;
+ }
+ return false;
+}
+
static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
{
return 0;
@@ -135,4 +293,5 @@ static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
struct pkvm_iommu_ops smmu_ops = {
.init = smmu_init,
.host_stage2_idmap = smmu_host_stage2_idmap,
+ .dabt_handler = smmu_dabt_handler,
};
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 14/25] iommu/arm-smmu-v3-kvm: Shadow the command queue
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (12 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 13/25] iommu/arm-smmu-v3-kvm: Add MMIO emulation Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 15/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions Mostafa Saleh
` (11 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
At boot, allocate a command queue per SMMU which is used as a shadow
by the hypervisor.
The command queue size is 64K which is more than enough, as the
hypervisor would consume all the entries per a command queue prod
write, which means it can handle up to 4096 at a time.
Then, the host command queue needs to be pinned in a shared state, so
it can't be donated to VMs, and avoid tricking the hypervisor into
accessing them. This is done each time the command queue is enabled,
and undone each time the command queue is disabled.
The hypervisor won't access the host command queue when it is disabled
from the host.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 25 ++++
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 10 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 124 ++++++++++++++++++
3 files changed, 159 insertions(+)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index 9947d3a44304..28f8b1fba8f7 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -15,6 +15,8 @@
#include "arm-smmu-v3.h"
#include "pkvm/arm-smmu-v3-hyp.h"
+#define SMMU_KVM_CMDQ_ORDER get_order(MAX(SZ_64K, PAGE_SIZE))
+
extern struct pkvm_iommu_ops kvm_nvhe_sym(smmu_ops);
static size_t kvm_arm_smmu_count;
@@ -24,6 +26,15 @@ static size_t kvm_arm_smmu_cur;
static void kvm_arm_smmu_array_free(void)
{
int order;
+ int i;
+
+ for (i = 0 ; i < kvm_arm_smmu_cur ; ++i) {
+ struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[i];
+
+ if (smmu->cmdq.base_dma)
+ free_pages((unsigned long)phys_to_virt(smmu->cmdq.base_dma),
+ SMMU_KVM_CMDQ_ORDER);
+ }
order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
free_pages((unsigned long)kvm_arm_smmu_array, order);
@@ -70,6 +81,7 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
struct device *dev = &pdev->dev;
struct resource *res;
+ void *cmdq_base;
/* Only device tree, ACPI not supported. */
if (!dev->of_node)
@@ -92,6 +104,19 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
return -EINVAL;
}
+ /*
+ * Allocate the shadow command queue, it doesn't have to be the same
+ * size as the host.
+ * Only populate base_dma and llq.max_n_shift, the hypervisor will init
+ * the rest.
+ */
+ cmdq_base = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, SMMU_KVM_CMDQ_ORDER);
+ if (!cmdq_base)
+ return -ENOMEM;
+
+ smmu->cmdq.base_dma = virt_to_phys(cmdq_base);
+ smmu->cmdq.llq.max_n_shift = SMMU_KVM_CMDQ_ORDER + PAGE_SHIFT - CMDQ_ENT_SZ_SHIFT;
+
if (of_dma_is_coherent(dev->of_node))
smmu->features |= ARM_SMMU_FEAT_COHERENCY;
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index 58fa14c239e3..39afdeffcd63 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -8,6 +8,8 @@
#include <nvhe/spinlock.h>
#endif
+#include "../arm-smmu-v3.h"
+
/*
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
@@ -21,6 +23,10 @@
* @lock Lock to protect SMMU emulation
* @hw_lock Lock to protect SMMU HW (as CMDQ)
* Order smmu.lock => host_mmu.lock => smmu.hw_lock
+ * @cmdq CMDQ as observed by HW
+ * @cmdq_host Host view of the CMDQ, only q_base and llq used.
+ * @cmdq_max_shift Max shift for the CMDQ probed from HW.
+ * @cr0 Last value of CR0
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -38,6 +44,10 @@ struct hyp_arm_smmu_v3_device {
u32 lock;
u32 hw_lock;
#endif
+ struct arm_smmu_queue cmdq;
+ struct arm_smmu_queue cmdq_host;
+ u32 cmdq_max_shift;
+ u32 cr0;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 7a51cb70205f..b26c21b595b4 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -22,11 +22,68 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
(smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
(smmu)++)
+#define cmdq_size(cmdq) ((1 << ((cmdq)->llq.max_n_shift)) * CMDQ_ENT_DWORDS * 8)
+
+static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_CMDQEN, smmu->cr0);
+}
+
+/*
+ * CMDQ, STE host copies are accessed by the hypervisor, we share them to
+ * - Prevent the host from passing protected VM memory.
+ * - Having them mapped in the hyp page table.
+ */
+static int smmu_share_pages(phys_addr_t addr, size_t size)
+{
+ size_t nr_pages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT;
+ phys_addr_t base = addr & PAGE_MASK;
+ int i, ret;
+
+ for (i = 0; i < nr_pages; ++i) {
+ if (__pkvm_host_share_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT)) {
+ while (i--)
+ __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ return -EPERM;
+ }
+ }
+
+ ret = hyp_pin_shared_mem(hyp_phys_to_virt(base),
+ hyp_phys_to_virt(base + nr_pages * PAGE_SIZE));
+ if (ret) {
+ for (i = 0; i < nr_pages; ++i)
+ __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ }
+
+ return ret;
+}
+
+static int smmu_unshare_pages(phys_addr_t addr, size_t size)
+{
+ size_t nr_pages = PAGE_ALIGN(size + (addr & ~PAGE_MASK)) >> PAGE_SHIFT;
+ phys_addr_t base = addr & PAGE_MASK;
+ int i, ret;
+
+ hyp_unpin_shared_mem(hyp_phys_to_virt(base),
+ hyp_phys_to_virt(base + nr_pages * PAGE_SIZE));
+
+ for (i = 0; i < nr_pages; ++i) {
+ ret = __pkvm_host_unshare_hyp((base + i * PAGE_SIZE) >> PAGE_SHIFT);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
WARN_ON(__pkvm_hyp_donate_host_mmio(hyp_phys_to_pfn(smmu->mmio_addr),
smmu->mmio_size >> PAGE_SHIFT));
+ if (smmu->cmdq.base)
+ WARN_ON(__pkvm_hyp_donate_host(smmu->cmdq.base_dma >> PAGE_SHIFT,
+ PAGE_ALIGN(cmdq_size(&smmu->cmdq)) >> PAGE_SHIFT));
smmu->base = NULL;
}
@@ -53,6 +110,7 @@ static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
return -EINVAL;
smmu->sid_bits = FIELD_GET(IDR1_SIDSIZE, reg);
+ smmu->cmdq_max_shift = FIELD_GET(IDR1_CMDQS, reg);
/* Follows the kernel logic */
if (smmu->sid_bits <= STRTAB_SPLIT)
smmu->features &= ~ARM_SMMU_FEAT_2_LVL_STRTAB;
@@ -71,6 +129,33 @@ static int smmu_probe(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+/*
+ * The kernel part of the driver will allocate the shadow cmdq,
+ * and zero it. This function only donates it.
+ */
+static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
+{
+ size_t cmdq_nr_pages;
+ int ret;
+
+ smmu->cmdq.llq.max_n_shift = min(smmu->cmdq.llq.max_n_shift, smmu->cmdq_max_shift);
+ cmdq_nr_pages = PAGE_ALIGN(cmdq_size(&smmu->cmdq)) >> PAGE_SHIFT;
+ ret = __pkvm_host_donate_hyp(smmu->cmdq.base_dma >> PAGE_SHIFT, cmdq_nr_pages);
+ if (ret)
+ return ret;
+
+ smmu->cmdq.base = hyp_phys_to_virt(smmu->cmdq.base_dma);
+ smmu->cmdq.prod_reg = smmu->base + ARM_SMMU_CMDQ_PROD;
+ smmu->cmdq.cons_reg = smmu->base + ARM_SMMU_CMDQ_CONS;
+ smmu->cmdq.q_base = smmu->cmdq.base_dma |
+ FIELD_PREP(Q_BASE_LOG2SIZE, smmu->cmdq.llq.max_n_shift);
+ smmu->cmdq.ent_dwords = CMDQ_ENT_DWORDS;
+ writel_relaxed(0, smmu->cmdq.prod_reg);
+ writel_relaxed(0, smmu->cmdq.cons_reg);
+ writeq_relaxed(smmu->cmdq.q_base, smmu->base + ARM_SMMU_CMDQ_BASE);
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -92,7 +177,12 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_init_cmdq(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
+
out_ret:
smmu_deinit_device(smmu);
return ret;
@@ -132,6 +222,23 @@ static int smmu_init(void)
return ret;
}
+static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
+
+ smmu->cmdq_host.llq.max_n_shift = min(shift, smmu->cmdq_max_shift);
+ smmu->cmdq_host.base_dma = smmu->cmdq_host.q_base & Q_BASE_ADDR_MASK;
+ smmu->cmdq_host.base_dma &= ~(cmdq_size(&smmu->cmdq_host) - 1);
+ WARN_ON(smmu_share_pages(smmu->cmdq_host.base_dma,
+ cmdq_size(&smmu->cmdq_host)));
+}
+
+static void smmu_emulate_cmdq_disable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(smmu_unshare_pages(smmu->cmdq_host.base_dma,
+ cmdq_size(&smmu->cmdq_host)));
+}
+
static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
struct user_pt_regs *regs,
u64 esr, u32 off)
@@ -158,6 +265,14 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
break;
/* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_CMDQ_BASE:
+ if (is_write) {
+ /* Not allowed by the architecture */
+ if (is_cmdq_enabled(smmu))
+ break;
+ smmu->cmdq_host.q_base = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_CMDQ_PROD:
case ARM_SMMU_CMDQ_CONS:
case ARM_SMMU_STRTAB_BASE:
@@ -168,6 +283,15 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
case ARM_SMMU_CR0:
if (len != sizeof(u32))
break;
+ if (is_write) {
+ bool last_cmdq_en = is_cmdq_enabled(smmu);
+
+ smmu->cr0 = val;
+ if (!last_cmdq_en && is_cmdq_enabled(smmu))
+ smmu_emulate_cmdq_enable(smmu);
+ else if (last_cmdq_en && !is_cmdq_enabled(smmu))
+ smmu_emulate_cmdq_disable(smmu);
+ }
mask = read_write;
break;
case ARM_SMMU_CR1:
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 15/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (13 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 14/25] iommu/arm-smmu-v3-kvm: Shadow the command queue Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 16/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host Mostafa Saleh
` (10 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add functions to access the command queue, there are 2 main usage:
- Hypervisor's own commands, as TLB invalidation, would use functions
as smmu_send_cmd(), which creates and sends a command.
- Add host commands to the shadow command queue, after being filtered,
these will be added with smmu_add_cmd_raw().
queue_space() is split out of queue_has_space() as it is going to
check the host shadow of the queue.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 14 ++-
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 118 ++++++++++++++++++
2 files changed, 126 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 28efa733e796..d48bd9f272e1 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -1225,19 +1225,21 @@ int arm_smmu_cmdq_issue_cmdlist(struct arm_smmu_device *smmu,
bool arm_smmu_erratum_repeat_tlbi_cfgi(void);
/* Queue and STE functions shared between kernel and hyp. */
-static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+static inline u32 queue_space(struct arm_smmu_ll_queue *q)
{
- u32 space, prod, cons;
+ u32 prod, cons;
prod = Q_IDX(q, q->prod);
cons = Q_IDX(q, q->cons);
if (Q_WRP(q, q->prod) == Q_WRP(q, q->cons))
- space = (1 << q->max_n_shift) - (prod - cons);
- else
- space = cons - prod;
+ return (1 << q->max_n_shift) - (prod - cons);
+ return cons - prod;
+}
- return space >= n;
+static inline bool queue_has_space(struct arm_smmu_ll_queue *q, u32 n)
+{
+ return queue_space(q) >= n;
}
static inline bool queue_full(struct arm_smmu_ll_queue *q)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index b26c21b595b4..38b8ecc5cc10 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -24,6 +24,41 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
#define cmdq_size(cmdq) ((1 << ((cmdq)->llq.max_n_shift)) * CMDQ_ENT_DWORDS * 8)
+static u32 timer_freq;
+
+static inline u64 hyp_clock_ns(void)
+{
+ return mul_u64_u32_div(__arch_counter_get_cntvct(), NSEC_PER_SEC, timer_freq);
+}
+
+#define ARM_SMMU_EL2_POLL_TIMEOUT_US 1000
+/*
+ * Wait until @cond is true, can use WFE, if polling on an SMMU and
+ * event that supports it.
+ * Return 0 on success, or -ETIMEDOUT
+ */
+#define smmu_wait(__use_wfe, __cond) \
+({ \
+ int __ret = 0; \
+ u64 __start = hyp_clock_ns(); \
+ u64 __timeout = ARM_SMMU_EL2_POLL_TIMEOUT_US * NSEC_PER_USEC; \
+ \
+ while (!(__cond)) { \
+ if (__use_wfe) { \
+ wfe(); \
+ } else { \
+ cpu_relax(); \
+ } \
+ if ((hyp_clock_ns() - __start) >= __timeout) { \
+ if (__cond) \
+ break; \
+ __ret = -ETIMEDOUT; \
+ break; \
+ } \
+ } \
+ __ret; \
+})
+
static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
{
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
@@ -76,6 +111,85 @@ static int smmu_unshare_pages(phys_addr_t addr, size_t size)
return 0;
}
+__maybe_unused
+static bool smmu_cmdq_has_space(struct arm_smmu_queue *cmdq, u32 n)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_has_space(llq, n);
+}
+
+static bool smmu_cmdq_full(struct arm_smmu_queue *cmdq)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_full(llq);
+}
+
+static bool smmu_cmdq_empty(struct arm_smmu_queue *cmdq)
+{
+ struct arm_smmu_ll_queue *llq = &cmdq->llq;
+
+ WRITE_ONCE(llq->cons, readl_relaxed(cmdq->cons_reg));
+ return queue_empty(llq);
+}
+
+static void smmu_add_cmd_raw(struct hyp_arm_smmu_v3_device *smmu,
+ u64 *cmd)
+{
+ struct arm_smmu_queue *q = &smmu->cmdq;
+ struct arm_smmu_ll_queue *llq = &q->llq;
+
+ queue_write(Q_ENT(q, llq->prod), cmd, CMDQ_ENT_DWORDS);
+ llq->prod = queue_inc_prod_n(llq, 1);
+}
+
+static int smmu_add_cmd(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmd *cmd)
+{
+ int ret;
+
+ hyp_assert_lock_held(&smmu->hw_lock);
+ ret = smmu_wait(false, !smmu_cmdq_full(&smmu->cmdq));
+ if (ret)
+ return ret;
+
+ smmu_add_cmd_raw(smmu, cmd->data);
+ writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+ return 0;
+}
+
+static int smmu_sync_cmd(struct hyp_arm_smmu_v3_device *smmu)
+{
+ int ret;
+ struct arm_smmu_cmd cmd;
+
+ hyp_assert_lock_held(&smmu->hw_lock);
+ cmd = arm_smmu_make_cmd_sync(CMDQ_SYNC_0_CS_SEV, 0);
+ ret = smmu_add_cmd(smmu, &cmd);
+ if (ret)
+ return ret;
+
+ return smmu_wait(smmu->features & ARM_SMMU_FEAT_SEV,
+ smmu_cmdq_empty(&smmu->cmdq));
+}
+
+__maybe_unused
+static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmd *cmd)
+{
+ int ret;
+
+ hyp_assert_lock_held(&smmu->hw_lock);
+ ret = smmu_add_cmd(smmu, cmd);
+ if (ret)
+ return ret;
+
+ return smmu_sync_cmd(smmu);
+}
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
@@ -197,6 +311,10 @@ static int smmu_init(void)
u64 pfn, nr_pages;
int ret;
+ timer_freq = read_sysreg(cntfrq_el0);
+ if (!timer_freq || timer_freq > NSEC_PER_SEC)
+ return -EINVAL;
+
kvm_hyp_arm_smmu_v3_smmus = kern_hyp_va(kvm_hyp_arm_smmu_v3_smmus);
pfn = hyp_virt_to_pfn(kvm_hyp_arm_smmu_v3_smmus);
nr_pages = smmu_arr_size >> PAGE_SHIFT;
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 16/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (14 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 15/25] iommu/arm-smmu-v3-kvm: Add CMDQ functions Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 17/25] iommu/arm-smmu-v3-kvm: Shadow stream table Mostafa Saleh
` (9 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Don't allow access to the command queue from the host:
- ARM_SMMU_CMDQ_BASE: Only allowed to be written when CMDQ is disabled, we
use it to keep track of the host command queue base.
Reads return the saved value.
- ARM_SMMU_CMDQ_PROD: Writes trigger command queue emulation which sanitise
and filters the whole range. Reads returns the host copy.
- ARM_SMMU_CMDQ_CONS: Writes move the sw copy of the cons, but the host
can't skip commands once submitted. Reads return the emulated value and
the error bits in the actual cons.
Also add emulation for IDR1.CMDQS to return the hypervisor command queue
size which can be equal to or smaller to the HW size.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 151 +++++++++++++++++-
1 file changed, 146 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 38b8ecc5cc10..8c67e348f4a3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -111,7 +111,6 @@ static int smmu_unshare_pages(phys_addr_t addr, size_t size)
return 0;
}
-__maybe_unused
static bool smmu_cmdq_has_space(struct arm_smmu_queue *cmdq, u32 n)
{
struct arm_smmu_ll_queue *llq = &cmdq->llq;
@@ -340,6 +339,105 @@ static int smmu_init(void)
return ret;
}
+static bool smmu_filter_command(struct hyp_arm_smmu_v3_device *smmu, u64 *command)
+{
+ u64 type = FIELD_GET(CMDQ_0_OP, command[0]);
+
+ switch (type) {
+ case CMDQ_OP_CFGI_STE:
+ /* TBD: SHADOW_STE*/
+ break;
+ case CMDQ_OP_CFGI_ALL:
+ {
+ /*
+ * Linux doesn't use range STE invalidation, and only use this
+ * for CFGI_ALL, which is done on reset and not on an new STE
+ * being used.
+ * Although, this is not architectural we rely on the current Linux
+ * implementation.
+ */
+ if ((FIELD_GET(CMDQ_CFGI_1_RANGE, command[1]) != 31))
+ return true;
+ break;
+ }
+ case CMDQ_OP_TLBI_NH_ASID:
+ case CMDQ_OP_TLBI_NH_VA:
+ case CMDQ_OP_TLBI_NH_ALL:
+ case 0x13: /* CMD_TLBI_NH_VAA: Not used by Linux */
+ {
+ /* Only allow VMID = 0 */
+ if (FIELD_GET(CMDQ_TLBI_0_VMID, command[0]) != 0)
+ return true;
+ break;
+ }
+ case CMDQ_OP_PREFETCH_CFG:
+ case CMDQ_OP_CFGI_CD:
+ case CMDQ_OP_CFGI_CD_ALL:
+ case CMDQ_OP_TLBI_NSNH_ALL:
+ case CMDQ_OP_PRI_RESP:
+ case CMDQ_OP_RESUME:
+ break;
+ case CMDQ_OP_CMD_SYNC:
+ if (FIELD_GET(CMDQ_SYNC_0_CS, command[0]) == CMDQ_SYNC_0_CS_IRQ) {
+ /* Do not allow MSI */
+ command[0] &= ~CMDQ_SYNC_0_CS;
+ command[0] |= FIELD_PREP(CMDQ_SYNC_0_CS, CMDQ_SYNC_0_CS_SEV);
+ command[1] &= ~CMDQ_SYNC_1_MSIADDR_MASK;
+ }
+ break;
+ default:
+ /* Deny unknown commands */
+ return true;
+ }
+
+ return false;
+}
+
+static int smmu_emulate_cmdq_insert(struct hyp_arm_smmu_v3_device *smmu)
+{
+ u64 *host_cmdq = hyp_phys_to_virt(smmu->cmdq_host.base_dma);
+ bool use_wfe = smmu->features & ARM_SMMU_FEAT_SEV;
+ u64 cmd[CMDQ_ENT_DWORDS];
+ int idx, ret;
+ u32 pending;
+ bool skip;
+
+ if (!is_cmdq_enabled(smmu))
+ return 0;
+
+ pending = (1 << (smmu->cmdq_host.llq.max_n_shift)) - queue_space(&smmu->cmdq_host.llq);
+
+ hyp_spin_lock(&smmu->hw_lock);
+ /* Wait for the command queue to have some space. */
+ ret = smmu_wait(use_wfe, smmu_cmdq_has_space(&smmu->cmdq, pending));
+ if (ret) {
+ hyp_spin_unlock(&smmu->hw_lock);
+ return ret;
+ }
+
+ while (pending--) {
+ int i;
+
+ idx = Q_IDX(&smmu->cmdq_host.llq, smmu->cmdq_host.llq.cons);
+ queue_inc_cons(&smmu->cmdq_host.llq);
+
+ /* Copy the command to local buffer avoiding TOCTOU */
+ for (i = 0; i < CMDQ_ENT_DWORDS; ++i)
+ cmd[i] = le64_to_cpu(READ_ONCE(host_cmdq[idx * CMDQ_ENT_DWORDS + i]));
+
+ skip = smmu_filter_command(smmu, cmd);
+ if (WARN_ON(skip))
+ continue;
+ smmu_add_cmd_raw(smmu, cmd);
+ }
+
+ writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+
+ ret = smmu_wait(use_wfe, smmu_cmdq_empty(&smmu->cmdq));
+ hyp_spin_unlock(&smmu->hw_lock);
+ return ret;
+}
+
static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
{
u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
@@ -381,18 +479,51 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
*/
mask = read_only & ~(IDR0_S2P | IDR0_VMID16 | IDR0_MSI | IDR0_HYP | IDR0_ATS);
break;
- /* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_CMDQ_BASE:
+ /*
+ * Although allowed to use smaller size, we rely on the SMMUv3 driver
+ * using 64-bit store instruction for simplicity.
+ */
+ if (len != sizeof(u64))
+ break;
if (is_write) {
/* Not allowed by the architecture */
if (is_cmdq_enabled(smmu))
break;
smmu->cmdq_host.q_base = val;
+ goto out_ret;
+ } else {
+ val = smmu->cmdq_host.q_base;
+ goto out_update_regs;
}
- mask = read_write;
- break;
case ARM_SMMU_CMDQ_PROD:
+ if (len != sizeof(u32))
+ break;
+ if (is_write) {
+ smmu->cmdq_host.llq.prod = val;
+ WARN_ON(smmu_emulate_cmdq_insert(smmu));
+ goto out_ret;
+ } else {
+ val = smmu->cmdq_host.llq.prod;
+ goto out_update_regs;
+ }
case ARM_SMMU_CMDQ_CONS:
+ if (len != sizeof(u32))
+ break;
+ if (is_write) {
+ if (WARN_ON(is_cmdq_enabled(smmu)))
+ break;
+
+ smmu->cmdq_host.llq.cons = val;
+ goto out_ret;
+ } else {
+ /* Propagate errors back to the host.*/
+ u32 cons = readl_relaxed(smmu->base + ARM_SMMU_CMDQ_CONS);
+
+ val = smmu->cmdq_host.llq.cons | (CMDQ_CONS_ERR & cons);
+ goto out_update_regs;
+ }
+ /* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_STRTAB_BASE:
case ARM_SMMU_STRTAB_BASE_CFG:
case ARM_SMMU_GBPA:
@@ -468,10 +599,20 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
mask = read_write;
break;
/* Allowed RO 32 bit registers. */
+ case ARM_SMMU_IDR1:
+ if (len != sizeof(u32))
+ break;
+ /* Cap CMDQS to the shadow queue size. */
+ if (!is_write) {
+ val = readl_relaxed(smmu->base + ARM_SMMU_IDR1);
+ val &= ~IDR1_CMDQS;
+ val |= FIELD_PREP(IDR1_CMDQS, smmu->cmdq.llq.max_n_shift);
+ goto out_update_regs;
+ }
+ fallthrough;
case ARM_SMMU_IIDR:
case ARM_SMMU_IDR5:
case ARM_SMMU_IDR3:
- case ARM_SMMU_IDR1:
case ARM_SMMU_GERROR:
if (len != sizeof(u32))
break;
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 17/25] iommu/arm-smmu-v3-kvm: Shadow stream table
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (15 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 16/25] iommu/arm-smmu-v3-kvm: Emulate CMDQ for host Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 18/25] iommu/arm-smmu-v3-kvm: Shadow STEs Mostafa Saleh
` (8 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Allocate the shadow stream table per SMMU.
We choose the size of that table to be 1MB which is the
max size used by host in the case of 2 levels.
All the host writes are still passthrough for bisectability, that
is changed next where CFGI commands will be trapped and used to
update the shadow copy that will be used by the HW.
Similar to the command queue, the host stream table is
shared/unshared each time the SMMU is enabled/disabled.
Handling of L2 tables is also done in the next patch when
the shadowing is added.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c | 21 ++-
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 10 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 122 ++++++++++++++++++
3 files changed, 152 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
index 28f8b1fba8f7..6b5a93dfbc2b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
@@ -16,6 +16,13 @@
#include "pkvm/arm-smmu-v3-hyp.h"
#define SMMU_KVM_CMDQ_ORDER get_order(MAX(SZ_64K, PAGE_SIZE))
+/*
+ * Use the max value of L1 the kernel uses, that also covers the worst case
+ * for linear tables as it is mandatory according to the spec to support 2
+ * lvl tables if SIDSIZE >= 7
+ */
+#define SMMU_KVM_STRTAB_ORDER (get_order(STRTAB_MAX_L1_ENTRIES * \
+ sizeof(struct arm_smmu_strtab_l1)))
extern struct pkvm_iommu_ops kvm_nvhe_sym(smmu_ops);
@@ -34,6 +41,9 @@ static void kvm_arm_smmu_array_free(void)
if (smmu->cmdq.base_dma)
free_pages((unsigned long)phys_to_virt(smmu->cmdq.base_dma),
SMMU_KVM_CMDQ_ORDER);
+ if (smmu->strtab_dma)
+ free_pages((unsigned long)phys_to_virt(smmu->strtab_dma),
+ SMMU_KVM_STRTAB_ORDER);
}
order = get_order(kvm_arm_smmu_count * sizeof(*kvm_arm_smmu_array));
@@ -80,8 +90,8 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
{
struct hyp_arm_smmu_v3_device *smmu = &kvm_arm_smmu_array[kvm_arm_smmu_cur];
struct device *dev = &pdev->dev;
+ void *cmdq_base, *strtab;
struct resource *res;
- void *cmdq_base;
/* Only device tree, ACPI not supported. */
if (!dev->of_node)
@@ -117,6 +127,15 @@ static int smmuv3_nesting_probe(struct platform_device *pdev)
smmu->cmdq.base_dma = virt_to_phys(cmdq_base);
smmu->cmdq.llq.max_n_shift = SMMU_KVM_CMDQ_ORDER + PAGE_SHIFT - CMDQ_ENT_SZ_SHIFT;
+ strtab = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, SMMU_KVM_STRTAB_ORDER);
+ if (!strtab) {
+ free_pages((unsigned long)cmdq_base, SMMU_KVM_CMDQ_ORDER);
+ return -ENOMEM;
+ }
+
+ smmu->strtab_dma = virt_to_phys(strtab);
+ smmu->strtab_size = PAGE_SIZE << SMMU_KVM_STRTAB_ORDER;
+
if (of_dma_is_coherent(dev->of_node))
smmu->features |= ARM_SMMU_FEAT_COHERENCY;
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index 39afdeffcd63..d4700d3a3c10 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -14,6 +14,8 @@
* Parameters from the trusted host:
* @mmio_addr base address of the SMMU registers
* @mmio_size size of the registers resource
+ * @strtab_dma Phys address of stream table
+ * @strtab_size Stream table size
*
* Other members are filled and used at runtime by the SMMU driver.
* @base Virtual address of SMMU registers
@@ -27,6 +29,9 @@
* @cmdq_host Host view of the CMDQ, only q_base and llq used.
* @cmdq_max_shift Max shift for the CMDQ probed from HW.
* @cr0 Last value of CR0
+ * @host_ste_cfg Host stream table config
+ * @host_ste_base Host stream table base
+ * @strtab_cfg Stream table as seen by HW
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -48,6 +53,11 @@ struct hyp_arm_smmu_v3_device {
struct arm_smmu_queue cmdq_host;
u32 cmdq_max_shift;
u32 cr0;
+ dma_addr_t strtab_dma;
+ size_t strtab_size;
+ u64 host_ste_cfg;
+ u64 host_ste_base;
+ struct arm_smmu_strtab_cfg strtab_cfg;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 8c67e348f4a3..54049b8b1363 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -17,6 +17,14 @@
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
+/* strtab accessors */
+#define strtab_log2size(smmu) (FIELD_GET(STRTAB_BASE_CFG_LOG2SIZE, (smmu)->host_ste_cfg))
+#define strtab_size(smmu) ((1UL << strtab_log2size(smmu)) * STRTAB_STE_DWORDS * 8)
+#define strtab_host_base(smmu) ((smmu)->host_ste_base & STRTAB_BASE_ADDR_MASK)
+#define strtab_split(smmu) (FIELD_GET(STRTAB_BASE_CFG_SPLIT, (smmu)->host_ste_cfg))
+#define strtab_l1_size(smmu) ((1UL << (strtab_log2size(smmu) - strtab_split(smmu))) * \
+ (sizeof(struct arm_smmu_strtab_l1)))
+
#define for_each_smmu(smmu) \
for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
(smmu) != &kvm_hyp_arm_smmu_v3_smmus[kvm_hyp_arm_smmu_v3_count]; \
@@ -64,6 +72,11 @@ static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
}
+static bool is_smmu_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_SMMUEN, smmu->cr0);
+}
+
/*
* CMDQ, STE host copies are accessed by the hypervisor, we share them to
* - Prevent the host from passing protected VM memory.
@@ -197,6 +210,11 @@ static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
if (smmu->cmdq.base)
WARN_ON(__pkvm_hyp_donate_host(smmu->cmdq.base_dma >> PAGE_SHIFT,
PAGE_ALIGN(cmdq_size(&smmu->cmdq)) >> PAGE_SHIFT));
+
+ if (smmu->strtab_cfg.linear.table ||
+ smmu->strtab_cfg.l2.l1tab)
+ WARN_ON(__pkvm_hyp_donate_host(hyp_phys_to_pfn(smmu->strtab_dma),
+ smmu->strtab_size >> PAGE_SHIFT));
smmu->base = NULL;
}
@@ -269,6 +287,45 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
+{
+ struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
+ int ret;
+ u32 reg;
+
+ ret = __pkvm_host_donate_hyp(hyp_phys_to_pfn(smmu->strtab_dma),
+ smmu->strtab_size >> PAGE_SHIFT);
+ if (ret)
+ return ret;
+
+ if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
+ unsigned int last_sid_idx =
+ arm_smmu_strtab_l1_idx((1ULL << smmu->sid_bits) - 1);
+
+ cfg->l2.l1tab = hyp_phys_to_virt(smmu->strtab_dma);
+ cfg->l2.l1_dma = smmu->strtab_dma;
+ cfg->l2.num_l1_ents = min(last_sid_idx + 1, STRTAB_MAX_L1_ENTRIES);
+
+ reg = FIELD_PREP(STRTAB_BASE_CFG_FMT,
+ STRTAB_BASE_CFG_FMT_2LVL) |
+ FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE,
+ ilog2(cfg->l2.num_l1_ents) + STRTAB_SPLIT) |
+ FIELD_PREP(STRTAB_BASE_CFG_SPLIT, STRTAB_SPLIT);
+ } else {
+ cfg->linear.table = hyp_phys_to_virt(smmu->strtab_dma);
+ cfg->linear.ste_dma = smmu->strtab_dma;
+ cfg->linear.num_ents = 1UL << smmu->sid_bits;
+ reg = FIELD_PREP(STRTAB_BASE_CFG_FMT,
+ STRTAB_BASE_CFG_FMT_LINEAR) |
+ FIELD_PREP(STRTAB_BASE_CFG_LOG2SIZE, smmu->sid_bits);
+ }
+
+ writeq_relaxed((smmu->strtab_dma & STRTAB_BASE_ADDR_MASK) | STRTAB_BASE_RA,
+ smmu->base + ARM_SMMU_STRTAB_BASE);
+ writel_relaxed(reg, smmu->base + ARM_SMMU_STRTAB_BASE_CFG);
+ return 0;
+}
+
static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
{
unsigned long haddr;
@@ -294,6 +351,10 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_init_strtab(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
out_ret:
@@ -438,6 +499,46 @@ static int smmu_emulate_cmdq_insert(struct hyp_arm_smmu_v3_device *smmu)
return ret;
}
+static int smmu_update_ste_shadow(struct hyp_arm_smmu_v3_device *smmu, bool enabled)
+{
+ size_t size;
+ u32 fmt = FIELD_GET(STRTAB_BASE_CFG_FMT, smmu->host_ste_cfg);
+
+ /* Linux doesn't change the fmt nor size of the strtab in the run time. */
+ if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
+ if ((fmt != STRTAB_BASE_CFG_FMT_2LVL) ||
+ (strtab_split(smmu) != STRTAB_SPLIT) ||
+ (strtab_log2size(smmu) > (ilog2(STRTAB_MAX_L1_ENTRIES) + STRTAB_SPLIT)) ||
+ (strtab_split(smmu) >= strtab_log2size(smmu)))
+ return -EINVAL;
+ size = strtab_l1_size(smmu);
+ } else {
+ if ((fmt != STRTAB_BASE_CFG_FMT_LINEAR) ||
+ (strtab_log2size(smmu) > smmu->sid_bits))
+ return -EINVAL;
+ size = strtab_size(smmu);
+ }
+
+ if (enabled)
+ return smmu_share_pages(strtab_host_base(smmu), size);
+
+ return smmu_unshare_pages(strtab_host_base(smmu), size);
+}
+
+static void smmu_emulate_enable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ /* Enabling SMMU without CMDQ, means TLB invalidation won't work. */
+ if (WARN_ON(!is_cmdq_enabled(smmu)))
+ return;
+
+ WARN_ON(smmu_update_ste_shadow(smmu, true));
+}
+
+static void smmu_emulate_disable(struct hyp_arm_smmu_v3_device *smmu)
+{
+ WARN_ON(smmu_update_ste_shadow(smmu, false));
+}
+
static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
{
u32 shift = smmu->cmdq_host.q_base & Q_BASE_LOG2SIZE;
@@ -525,7 +626,23 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
}
/* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_STRTAB_BASE:
+ if (is_write) {
+ /* Must only be written when SMMU_CR0.SMMUEN == 0.*/
+ if (is_smmu_enabled(smmu))
+ break;
+ smmu->host_ste_base = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_STRTAB_BASE_CFG:
+ if (is_write) {
+ /* Must only be written when SMMU_CR0.SMMUEN == 0.*/
+ if (is_smmu_enabled(smmu))
+ break;
+ smmu->host_ste_cfg = val;
+ }
+ mask = read_write;
+ break;
case ARM_SMMU_GBPA:
mask = read_write;
break;
@@ -534,12 +651,17 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
break;
if (is_write) {
bool last_cmdq_en = is_cmdq_enabled(smmu);
+ bool last_smmu_en = is_smmu_enabled(smmu);
smmu->cr0 = val;
if (!last_cmdq_en && is_cmdq_enabled(smmu))
smmu_emulate_cmdq_enable(smmu);
else if (last_cmdq_en && !is_cmdq_enabled(smmu))
smmu_emulate_cmdq_disable(smmu);
+ if (!last_smmu_en && is_smmu_enabled(smmu))
+ smmu_emulate_enable(smmu);
+ else if (last_smmu_en && !is_smmu_enabled(smmu))
+ smmu_emulate_disable(smmu);
}
mask = read_write;
break;
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 18/25] iommu/arm-smmu-v3-kvm: Shadow STEs
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (16 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 17/25] iommu/arm-smmu-v3-kvm: Shadow stream table Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 19/25] iommu/arm-smmu-v3-kvm: Share other queues Mostafa Saleh
` (7 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Add STE emulation, when the host sends the CFGI_STE command.
Copy the STE as is to the shadow owned by the hypervisor,
which is the one seen by HW.
In the next patch, stage-2 page table will be attached.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 124 +++++++++++++++++-
1 file changed, 118 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 54049b8b1363..cb9aa7e4a394 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -24,6 +24,9 @@ struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
#define strtab_split(smmu) (FIELD_GET(STRTAB_BASE_CFG_SPLIT, (smmu)->host_ste_cfg))
#define strtab_l1_size(smmu) ((1UL << (strtab_log2size(smmu) - strtab_split(smmu))) * \
(sizeof(struct arm_smmu_strtab_l1)))
+#define strtab_hyp_base(smmu) ((smmu)->features & ARM_SMMU_FEAT_2_LVL_STRTAB ? \
+ (u64 *)(smmu)->strtab_cfg.l2.l1tab :\
+ (u64 *)(smmu)->strtab_cfg.linear.table)
#define for_each_smmu(smmu) \
for ((smmu) = kvm_hyp_arm_smmu_v3_smmus; \
@@ -287,6 +290,91 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
+ struct arm_smmu_ste *host_ste_out)
+{
+ u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+ struct arm_smmu_strtab_l1 host_l1_desc;
+ struct arm_smmu_strtab_l2 *l2ptr;
+ phys_addr_t host_l2_tab;
+ int ret, i;
+
+ host_l1_desc.l2ptr = READ_ONCE(host_ste_base[arm_smmu_strtab_l1_idx(sid)]);
+ if (!(le64_to_cpu(host_l1_desc.l2ptr) & STRTAB_L1_DESC_SPAN))
+ return -EINVAL;
+
+ host_l2_tab = le64_to_cpu(host_l1_desc.l2ptr) & STRTAB_L1_DESC_L2PTR_MASK;
+ /* Share and pin the table before accessing it. */
+ ret = smmu_share_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2));
+ if (ret)
+ return ret;
+
+ l2ptr = hyp_phys_to_virt(host_l2_tab);
+
+ for (i = 0; i < STRTAB_STE_DWORDS; ++i)
+ host_ste_out->data[i] =
+ READ_ONCE(l2ptr->stes[arm_smmu_strtab_l2_idx(sid)].data[i]);
+
+ WARN_ON(smmu_unshare_pages(host_l2_tab, sizeof(struct arm_smmu_strtab_l2)));
+ return 0;
+}
+
+static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool leaf)
+{
+ struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
+ struct arm_smmu_ste *hyp_ste_ptr, *host_ste_ptr, host_ste_copy;
+ u64 *hyp_ste_base = strtab_hyp_base(smmu);
+ int ret, i;
+
+ /* Leaf = 0 is not supported, as the kernel driver. */
+ if (!leaf || !is_smmu_enabled(smmu) ||
+ (sid >= (1UL << strtab_log2size(smmu))))
+ return -EINVAL;
+
+ if (!(smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB)) {
+ struct arm_smmu_ste *hyp_table = (struct arm_smmu_ste *)hyp_ste_base;
+ u64 *host_ste_base = hyp_phys_to_virt(strtab_host_base(smmu));
+ struct arm_smmu_ste *host_table = (struct arm_smmu_ste *)host_ste_base;
+
+ if (sid >= cfg->linear.num_ents)
+ return -E2BIG;
+
+ hyp_ste_ptr = &hyp_table[sid];
+ host_ste_ptr = &host_table[sid];
+ } else {
+ struct arm_smmu_strtab_l1 *l1tab = (struct arm_smmu_strtab_l1 *)hyp_ste_base;
+ u32 l1_idx = arm_smmu_strtab_l1_idx(sid);
+ struct arm_smmu_strtab_l2 *l2ptr;
+
+ if (l1_idx >= cfg->l2.num_l1_ents)
+ return -E2BIG;
+
+ host_ste_ptr = &host_ste_copy;
+ ret = smmu_get_host_l2_ste(smmu, sid, host_ste_ptr);
+ if (ret)
+ return ret;
+
+ /* No hypervisor entry, first time the L2 is populated. */
+ if (!l1tab[l1_idx].l2ptr) {
+ struct arm_smmu_strtab_l2 *l2table;
+
+ l2table = pkvm_iommu_alloc_pages(get_order(sizeof(*l2table)));
+ if (!l2table)
+ return -ENOMEM;
+ /* Ensure L2 is observed before writing the ptr. */
+ dma_wmb();
+ arm_smmu_write_strtab_l1_desc(&l1tab[l1_idx], hyp_virt_to_phys(l2table));
+ }
+ l2ptr = hyp_phys_to_virt(le64_to_cpu(l1tab[l1_idx].l2ptr) &
+ STRTAB_L1_DESC_L2PTR_MASK);
+ hyp_ste_ptr = &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)];
+ }
+
+ for (i = 0; i < STRTAB_STE_DWORDS; ++i)
+ WRITE_ONCE(hyp_ste_ptr->data[i], host_ste_ptr->data[i]);
+ return 0;
+}
+
static int smmu_init_strtab(struct hyp_arm_smmu_v3_device *smmu)
{
struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
@@ -406,8 +494,24 @@ static bool smmu_filter_command(struct hyp_arm_smmu_v3_device *smmu, u64 *comman
switch (type) {
case CMDQ_OP_CFGI_STE:
- /* TBD: SHADOW_STE*/
+ {
+ u32 leaf = FIELD_GET(CMDQ_CFGI_1_LEAF, command[1]);
+ u32 sid = FIELD_GET(CMDQ_CFGI_0_SID, command[0]);
+ int ret;
+
+ /*
+ * If STE update is required, flush the CMDQ and drop the lock as that
+ * might require to update the host page table and acquire its lock.
+ */
+ writel(smmu->cmdq.llq.prod, smmu->cmdq.prod_reg);
+ hyp_spin_unlock(&smmu->hw_lock);
+ ret = smmu_reshadow_ste(smmu, sid, leaf);
+ hyp_spin_lock(&smmu->hw_lock);
+ if (ret)
+ return true;
+
break;
+ }
case CMDQ_OP_CFGI_ALL:
{
/*
@@ -624,25 +728,33 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
val = smmu->cmdq_host.llq.cons | (CMDQ_CONS_ERR & cons);
goto out_update_regs;
}
- /* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_STRTAB_BASE:
+ if (len != sizeof(u64))
+ break;
if (is_write) {
/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
if (is_smmu_enabled(smmu))
break;
smmu->host_ste_base = val;
+ goto out_ret;
+ } else {
+ val = smmu->host_ste_base;
+ goto out_update_regs;
}
- mask = read_write;
- break;
case ARM_SMMU_STRTAB_BASE_CFG:
+ if (len != sizeof(u32))
+ break;
if (is_write) {
/* Must only be written when SMMU_CR0.SMMUEN == 0.*/
if (is_smmu_enabled(smmu))
break;
smmu->host_ste_cfg = val;
+ goto out_ret;
+ } else {
+ val = smmu->host_ste_cfg;
+ goto out_update_regs;
}
- mask = read_write;
- break;
+ /* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_GBPA:
mask = read_write;
break;
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 19/25] iommu/arm-smmu-v3-kvm: Share other queues
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (17 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 18/25] iommu/arm-smmu-v3-kvm: Shadow STEs Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 20/25] iommu/arm-smmu-v3-kvm: Emulate GBPA Mostafa Saleh
` (6 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Other queues as PRIQ and EVTQ do not need to be shadowed. However, we
need to make sure they are in a state that disallow them to be donated
to the hypervisor or guests. So, keep track of those and share them when
they get enabled.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 8 ++
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 81 +++++++++++++++++--
2 files changed, 84 insertions(+), 5 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index d4700d3a3c10..ffc57182e57e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -32,6 +32,10 @@
* @host_ste_cfg Host stream table config
* @host_ste_base Host stream table base
* @strtab_cfg Stream table as seen by HW
+ * @evtq_base Host evtq base reg
+ * @priq_base Host priq base reg
+ * @evtq_shared Whether the EVTQ was shared
+ * @priq_shared Whether the PRIQ was shared
*/
struct hyp_arm_smmu_v3_device {
phys_addr_t mmio_addr;
@@ -58,6 +62,10 @@ struct hyp_arm_smmu_v3_device {
u64 host_ste_cfg;
u64 host_ste_base;
struct arm_smmu_strtab_cfg strtab_cfg;
+ u64 evtq_base;
+ u64 priq_base;
+ bool evtq_shared;
+ bool priq_shared;
};
extern size_t kvm_nvhe_sym(kvm_hyp_arm_smmu_v3_count);
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index cb9aa7e4a394..00528380774f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -80,6 +80,16 @@ static bool is_smmu_enabled(struct hyp_arm_smmu_v3_device *smmu)
return FIELD_GET(CR0_SMMUEN, smmu->cr0);
}
+static bool is_evtq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_EVTQEN, smmu->cr0);
+}
+
+static bool is_priq_enabled(struct hyp_arm_smmu_v3_device *smmu)
+{
+ return FIELD_GET(CR0_PRIQEN, smmu->cr0);
+}
+
/*
* CMDQ, STE host copies are accessed by the hypervisor, we share them to
* - Prevent the host from passing protected VM memory.
@@ -660,6 +670,20 @@ static void smmu_emulate_cmdq_disable(struct hyp_arm_smmu_v3_device *smmu)
cmdq_size(&smmu->cmdq_host)));
}
+static void smmu_emulate_queue(struct hyp_arm_smmu_v3_device *smmu,
+ unsigned long q_base, size_t ent_size_shift)
+{
+ /* Q_BASE_ADDR_MASK is not enough as the SMMU also ignores bits > OAS */
+ phys_addr_t base = q_base & Q_BASE_ADDR_MASK & ((1ULL << smmu->oas) - 1);
+ size_t size = 1UL << (FIELD_GET(Q_BASE_LOG2SIZE, q_base) + ent_size_shift);
+
+ /* The host must program the base first and it must be aligned to size. */
+ if (WARN_ON(!q_base || (base & (size - 1))))
+ return;
+
+ WARN_ON(smmu_share_pages(base, size));
+}
+
static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
struct user_pt_regs *regs,
u64 esr, u32 off)
@@ -764,12 +788,34 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
if (is_write) {
bool last_cmdq_en = is_cmdq_enabled(smmu);
bool last_smmu_en = is_smmu_enabled(smmu);
+ bool last_evtq_en = is_evtq_enabled(smmu);
+ bool last_priq_en = is_priq_enabled(smmu);
smmu->cr0 = val;
if (!last_cmdq_en && is_cmdq_enabled(smmu))
smmu_emulate_cmdq_enable(smmu);
else if (last_cmdq_en && !is_cmdq_enabled(smmu))
smmu_emulate_cmdq_disable(smmu);
+
+ /*
+ * Share PRI and EVTQ to avoid the host using them to write to
+ * protected memory. However, do not unshare the queues at disable
+ * as that is more complicated, unsharing from here can lead to
+ * use-after-unshare issues, and requires ordering with cr0ack.
+ * The host can disable those queues during shutdown, but it never
+ * changes the base address (even with RPM), so leave the queue
+ * shared and assert that multiple host writes do not change it.
+ */
+ if (!last_evtq_en && is_evtq_enabled(smmu) && !smmu->evtq_shared) {
+ smmu_emulate_queue(smmu, smmu->evtq_base, EVTQ_ENT_SZ_SHIFT);
+ smmu->evtq_shared = true;
+ }
+
+ if (!last_priq_en && is_priq_enabled(smmu) && !smmu->priq_shared) {
+ smmu_emulate_queue(smmu, smmu->priq_base, PRIQ_ENT_SZ_SHIFT);
+ smmu->priq_shared = true;
+ }
+
if (!last_smmu_en && is_smmu_enabled(smmu))
smmu_emulate_enable(smmu);
else if (last_smmu_en && !is_smmu_enabled(smmu))
@@ -792,6 +838,34 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
mask = read_write;
break;
+ case ARM_SMMU_EVTQ_BASE:
+ if (len != sizeof(u64))
+ break;
+
+ if (is_write) {
+ /* See ARM_SMMU_CR0 */
+ if (is_evtq_enabled(smmu) ||
+ (smmu->evtq_shared && (smmu->evtq_base != val)))
+ break;
+ smmu->evtq_base = val;
+ }
+ mask = read_write;
+ break;
+
+ case ARM_SMMU_PRIQ_BASE:
+ if (len != sizeof(u64))
+ break;
+
+ if (is_write) {
+ /* See ARM_SMMU_CR0 */
+ if (is_priq_enabled(smmu) ||
+ (smmu->priq_shared && (smmu->priq_base != val)))
+ break;
+ smmu->priq_base = val;
+ }
+ mask = read_write;
+ break;
+
/* Allowed 32 bit registers. */
case ARM_SMMU_EVTQ_IRQ_CFG1:
case ARM_SMMU_EVTQ_IRQ_CFG2:
@@ -821,15 +895,12 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
case ARM_SMMU_EVTQ_IRQ_CFG0:
case ARM_SMMU_PRIQ_IRQ_CFG0:
case ARM_SMMU_GERROR_IRQ_CFG0:
+ if (len != sizeof(u64))
+ break;
/* These are RES0 as MSI support is hidden. */
val = 0;
if (!is_write)
goto out_update_regs;
- fallthrough;
- case ARM_SMMU_EVTQ_BASE:
- case ARM_SMMU_PRIQ_BASE:
- if (len != sizeof(u64))
- break;
mask = read_write;
break;
/* Allowed RO 32 bit registers. */
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 20/25] iommu/arm-smmu-v3-kvm: Emulate GBPA
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (18 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 19/25] iommu/arm-smmu-v3-kvm: Share other queues Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 21/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor Mostafa Saleh
` (5 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The last bit of emulation is GBPA. it must be always set to ABORT,
as when the SMMU is disabled it's not allowed for the host to bypass
the SMMU.
That's is done by setting the GBPA to ABORT at init time, and host
writes are always ignored and host reads always return ABORT.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 32 +++++++++++++++++--
1 file changed, 29 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 00528380774f..6e023e968ed3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -215,6 +215,22 @@ static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
return smmu_sync_cmd(smmu);
}
+static int smmu_abort_gbpa(struct hyp_arm_smmu_v3_device *smmu)
+{
+ int ret;
+ u32 reg;
+
+ ret = smmu_wait(false,
+ (readl_relaxed(smmu->base + ARM_SMMU_GBPA) & GBPA_UPDATE) == 0);
+ if (ret)
+ return ret;
+
+ reg = readl_relaxed(smmu->base + ARM_SMMU_GBPA);
+ writel_relaxed(GBPA_UPDATE | GBPA_ABORT | reg, smmu->base + ARM_SMMU_GBPA);
+ return smmu_wait(false,
+ (readl_relaxed(smmu->base + ARM_SMMU_GBPA) & GBPA_UPDATE) == 0);
+}
+
/* Put the device in a state that can be probed by the host driver. */
static void smmu_deinit_device(struct hyp_arm_smmu_v3_device *smmu)
{
@@ -453,6 +469,10 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
if (ret)
goto out_ret;
+ ret = smmu_abort_gbpa(smmu);
+ if (ret)
+ goto out_ret;
+
return 0;
out_ret:
@@ -778,10 +798,16 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
val = smmu->host_ste_cfg;
goto out_update_regs;
}
- /* Passthrough the register access for bisectability, handled later */
case ARM_SMMU_GBPA:
- mask = read_write;
- break;
+ if (len != sizeof(u32))
+ break;
+
+ /* Ignore write, always read to abort. */
+ if (!is_write) {
+ val = GBPA_ABORT;
+ goto out_update_regs;
+ }
+ goto out_ret;
case ARM_SMMU_CR0:
if (len != sizeof(u32))
break;
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 21/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (19 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 20/25] iommu/arm-smmu-v3-kvm: Emulate GBPA Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 22/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table Mostafa Saleh
` (4 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
To be able to populate the shadow stage-2 in the hypervisor, compile
io-pgtable-arm object for the hypervisor.
That requires the hypervisor to provide the iommu-pages allocator,
redefine the address conversion helpers, and stub out the DMA API.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 3 +-
.../arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h | 86 +++++++++++++++++++
drivers/iommu/io-pgtable-arm.c | 14 +--
drivers/iommu/io-pgtable-arm.h | 9 ++
4 files changed, 104 insertions(+), 8 deletions(-)
create mode 100644 drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index aa76c0f3f147..64bfd9992d9e 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -36,7 +36,8 @@ hyp-obj-y += $(lib-objs)
HYP_SMMU_V3_DRV_PATH = ../../../../../drivers/iommu/arm/arm-smmu-v3
hyp-obj-$(CONFIG_ARM_SMMU_V3_PKVM) += $(HYP_SMMU_V3_DRV_PATH)/pkvm/arm-smmu-v3.o \
- $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o ../../../../../lib/hweight.o
+ $(HYP_SMMU_V3_DRV_PATH)/arm-smmu-v3-common-lib.o ../../../../../lib/hweight.o \
+ $(HYP_SMMU_V3_DRV_PATH)/../../io-pgtable-arm.o
# Path to simple_ring_buffer.c
CFLAGS_trace.nvhe.o += -I$(srctree)/kernel/trace/
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h
new file mode 100644
index 000000000000..16313814e5f8
--- /dev/null
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h
@@ -0,0 +1,86 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef IO_PGTABLE_ARM_HYP_H_
+#define IO_PGTABLE_ARM_HYP_H_
+
+#include <nvhe/memory.h>
+#include <nvhe/iommu.h>
+
+#undef WARN_ONCE
+#define WARN_ONCE(condition, format...) WARN_ON(condition)
+
+static inline void *iommu_alloc_pages_node_sz(int nid, gfp_t gfp, size_t size)
+{
+ return pkvm_iommu_alloc_pages(get_order(size));
+}
+
+static inline void iommu_free_pages(void *virt)
+{
+ pkvm_iommu_free_pages(virt);
+}
+
+#define arm_lpae_alloc_data(type) pkvm_iommu_alloc_pages(get_order(sizeof(type)))
+#define arm_lpae_free_data(p) pkvm_iommu_free_pages(p)
+
+#undef phys_to_virt
+#define phys_to_virt(x) hyp_phys_to_virt(x)
+
+#undef virt_to_phys
+#define virt_to_phys(x) hyp_virt_to_phys(x)
+
+/* Stubs used by io-pgtable-arm but no relevant for hypervisor object. */
+#undef dma_map_single
+#define dma_map_single(d, p, s, dir) (virt_to_phys(p))
+
+#undef dma_unmap_single
+#define dma_unmap_single(d, a, s, r) \
+ do { (void)(d); (void)(a); (void)(s); (void)(r); } while (0)
+
+#define dma_sync_single_for_device(d, a, s, r) \
+ do { (void)(d); (void)(a); (void)(s); (void)(r); } while (0)
+
+#undef dma_mapping_error
+#define dma_mapping_error(...) (0)
+
+#undef dev_err
+#define dev_err(dev, format, ...)
+
+#undef iommu_dirty_bitmap_record
+#define iommu_dirty_bitmap_record(d, i, l) \
+ do { (void)(d); (void)(i); (void)(l); } while (0)
+
+static inline int iommu_pages_start_incoherent(void *virt, struct device *dma_dev)
+{
+ return 0;
+}
+
+static inline void iommu_pages_free_incoherent(void *virt,
+ struct device *dma_dev)
+{
+}
+
+static inline void iommu_pages_flush_incoherent(struct device *dma_dev,
+ void *virt, size_t offset,
+ size_t len)
+{
+}
+
+static inline struct io_pgtable_ops *kvm_alloc_io_pgtable_ops(enum io_pgtable_fmt fmt,
+ struct io_pgtable_cfg *cfg,
+ void *cookie)
+{
+ struct io_pgtable *iop;
+
+ if (fmt != ARM_64_LPAE_S2)
+ return NULL;
+
+ iop = io_pgtable_arm_64_lpae_s2_init_fns.alloc(cfg, cookie);
+ if (!iop)
+ return NULL;
+
+ iop->fmt = fmt;
+ iop->cookie = cookie;
+ iop->cfg = *cfg;
+
+ return &iop->ops;
+}
+#endif /* IO_PGTABLE_ARM_HYP_H_ */
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 476c0e25631a..6b2668c2ef44 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -20,7 +20,6 @@
#include <asm/barrier.h>
#include "io-pgtable-arm.h"
-#include "iommu-pages.h"
#define ARM_LPAE_MAX_ADDR_BITS 52
#define ARM_LPAE_S2_MAX_CONCAT_PAGES 16
@@ -301,6 +300,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
{
struct device *dev = cfg->iommu_dev;
void *pages;
+ int nid = dev ? dev_to_node(dev) : NUMA_NO_NODE;
/*
* For very small starting-level translation tables the HW requires a
@@ -311,7 +311,7 @@ static void *__arm_lpae_alloc_pages(size_t size, gfp_t gfp,
if (cfg->alloc)
return __arm_lpae_cfg_alloc(size, gfp, cfg, cookie);
- pages = iommu_alloc_pages_node_sz(dev_to_node(dev), gfp, size);
+ pages = iommu_alloc_pages_node_sz(nid, gfp, size);
if (!pages)
return NULL;
@@ -650,7 +650,7 @@ static void arm_lpae_free_pgtable(struct io_pgtable *iop)
struct arm_lpae_io_pgtable *data = io_pgtable_to_data(iop);
__arm_lpae_free_pgtable(data, data->start_level, data->pgd);
- kfree(data);
+ arm_lpae_free_data(data);
}
static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
@@ -964,7 +964,7 @@ arm_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg)
if (cfg->oas > ARM_LPAE_MAX_ADDR_BITS)
return NULL;
- data = kmalloc_obj(*data);
+ data = arm_lpae_alloc_data(*data);
if (!data)
return NULL;
@@ -1091,7 +1091,7 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie)
return &data->iop;
out_free_data:
- kfree(data);
+ arm_lpae_free_data(data);
return NULL;
}
@@ -1187,7 +1187,7 @@ arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie)
return &data->iop;
out_free_data:
- kfree(data);
+ arm_lpae_free_data(data);
return NULL;
}
@@ -1266,7 +1266,7 @@ arm_mali_lpae_alloc_pgtable(struct io_pgtable_cfg *cfg, void *cookie)
return &data->iop;
out_free_data:
- kfree(data);
+ arm_lpae_free_data(data);
return NULL;
}
diff --git a/drivers/iommu/io-pgtable-arm.h b/drivers/iommu/io-pgtable-arm.h
index ba7cfdf7afa0..ca765aea8745 100644
--- a/drivers/iommu/io-pgtable-arm.h
+++ b/drivers/iommu/io-pgtable-arm.h
@@ -27,4 +27,13 @@
#define ARM_LPAE_TCR_PS_48_BIT 0x5ULL
#define ARM_LPAE_TCR_PS_52_BIT 0x6ULL
+#ifndef __KVM_NVHE_HYPERVISOR__
+#include "iommu-pages.h"
+#define arm_lpae_alloc_data(type) kmalloc_obj(type)
+#define arm_lpae_free_data(p) kfree(p)
+
+#else
+#include "arm/arm-smmu-v3/pkvm/io-pgtable-arm-hyp.h"
+#endif
+
#endif /* IO_PGTABLE_ARM_H_ */
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 22/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (20 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 21/25] iommu/io-pgtable-arm: Support io-pgtable-arm in the hypervisor Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 23/25] iommu/arm-smmu-v3-kvm: Invalidate the SMMU TLBs Mostafa Saleh
` (3 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
The hypervisor calls back into the driver on every change to the host
stage-2 page table.
Mirror those changes into an identity mapped stage-2 for the SMMUv3,
That would be attached to all active SIDs.
Difference between memory and MMIO handling:
- Memory is always mapped with PAGE_SIZE. io-pgtable-arm no longer
supports split_blk_unmap, so a block cannot be broken into a table
once it is mapped, and pages are donated back and forth at PAGE_SIZE
granularity. The page table pool is sized to cover all of memory at
that granularity.
- MMIO is mapped with the largest block that fits, as it is assumed to
cover the whole IAS that is not memory while pKVM only reserves 1G
for the page table. MMIO is never donated at runtime, so it is never
unmapped and never needs a block to be split.
The TLB maintenance ops are left as stubs, they are implemented in the
next patch.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 153 +++++++++++++++++-
1 file changed, 152 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 6e023e968ed3..6f0ea3a4e48d 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -14,6 +14,9 @@
#include "../arm-smmu-v3.h"
#include "../arm-smmu-v3-common-lib.h"
+#include <linux/io-pgtable.h>
+#include "../../../io-pgtable-arm.h"
+
size_t __ro_after_init kvm_hyp_arm_smmu_v3_count;
struct hyp_arm_smmu_v3_device *kvm_hyp_arm_smmu_v3_smmus;
@@ -70,6 +73,9 @@ static inline u64 hyp_clock_ns(void)
__ret; \
})
+/* Protected by host_mmu.lock from core code. */
+static struct io_pgtable *idmap_pgtable;
+
static bool is_cmdq_enabled(struct hyp_arm_smmu_v3_device *smmu)
{
return FIELD_GET(CR0_CMDQEN, smmu->cr0);
@@ -215,6 +221,24 @@ static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
return smmu_sync_cmd(smmu);
}
+static void smmu_tlb_flush_walk(unsigned long iova, size_t size,
+ size_t granule, void *cookie)
+{
+ /* TBD: Invalidate the range in all the SMMUs. */
+}
+
+static void smmu_tlb_add_page(struct iommu_iotlb_gather *gather,
+ unsigned long iova, size_t granule,
+ void *cookie)
+{
+ /* TBD: Invalidate the granule in all the SMMUs. */
+}
+
+static const struct iommu_flush_ops smmu_tlb_ops = {
+ .tlb_flush_walk = smmu_tlb_flush_walk,
+ .tlb_add_page = smmu_tlb_add_page,
+};
+
static int smmu_abort_gbpa(struct hyp_arm_smmu_v3_device *smmu)
{
int ret;
@@ -480,6 +504,38 @@ static int smmu_init_device(struct hyp_arm_smmu_v3_device *smmu)
return ret;
}
+static int smmu_init_pgt(void)
+{
+ /* Default values overridden based on SMMUs common features. */
+ struct io_pgtable_cfg cfg = (struct io_pgtable_cfg) {
+ .tlb = &smmu_tlb_ops,
+ .pgsize_bitmap = ~0UL,
+ .ias = 48,
+ .oas = 48,
+ .coherent_walk = true,
+ .quirks = IO_PGTABLE_QUIRK_NO_WARN,
+ };
+ struct hyp_arm_smmu_v3_device *smmu;
+ struct io_pgtable_ops *ops;
+
+ for_each_smmu(smmu) {
+ cfg.ias = min(cfg.ias, smmu->oas);
+ cfg.oas = min(cfg.oas, smmu->oas);
+ cfg.pgsize_bitmap &= smmu->pgsize_bitmap;
+ cfg.coherent_walk &= !!(smmu->features & ARM_SMMU_FEAT_COHERENCY);
+ }
+
+ /* At least PAGE_SIZE must be supported by all SMMUs */
+ if ((cfg.pgsize_bitmap & PAGE_SIZE) == 0)
+ return -EINVAL;
+
+ ops = kvm_alloc_io_pgtable_ops(ARM_64_LPAE_S2, &cfg, NULL);
+ if (!ops)
+ return -ENOMEM;
+ idmap_pgtable = io_pgtable_ops_to_pgtable(ops);
+ return 0;
+}
+
/* Called while is the host is still trusted. */
static int smmu_init(void)
{
@@ -509,7 +565,10 @@ static int smmu_init(void)
BUILD_BUG_ON(sizeof(hyp_spinlock_t) != sizeof(u32));
- return 0;
+ ret = smmu_init_pgt();
+ if (ret)
+ goto out_reclaim_smmu;
+ return ret;
out_reclaim_smmu:
while (smmu != kvm_hyp_arm_smmu_v3_smmus)
@@ -998,8 +1057,100 @@ static bool smmu_dabt_handler(struct user_pt_regs *regs, u64 esr, u64 addr)
return false;
}
+static size_t smmu_pgsize_idmap(size_t size, u64 paddr, size_t pgsize_bitmap)
+{
+ size_t pgsizes;
+
+ /* Remove page sizes that are larger than the current size */
+ pgsizes = pgsize_bitmap & GENMASK_ULL(__fls(size), 0);
+
+ /* Remove page sizes that the address is not aligned to. */
+ if (likely(paddr))
+ pgsizes &= GENMASK_ULL(__ffs(paddr), 0);
+
+ WARN_ON(!pgsizes);
+
+ /* Return the largest page size that fits. */
+ return BIT(__fls(pgsizes));
+}
+
static int smmu_host_stage2_idmap(phys_addr_t start, phys_addr_t end, int prot)
{
+ size_t pgsize = PAGE_SIZE, pgcount, size;
+ struct io_pgtable *pgtable = idmap_pgtable;
+ int ret = 0;
+
+ end = min(end, BIT(pgtable->cfg.oas));
+ if (start >= end)
+ return 0;
+
+ size = end - start;
+ if (prot) {
+ size_t mapped;
+
+ if (!(prot & IOMMU_MMIO))
+ prot |= IOMMU_CACHE;
+
+ while (size) {
+ mapped = 0;
+ /*
+ * We handle pages size for memory and MMIO differently:
+ * - memory: Map everything with PAGE_SIZE, that is guaranteed to
+ * find memory as we allocated enough pages to cover the entire
+ * memory, we do that as io-pgtable-arm doesn't support
+ * split_blk_unmap logic any more, so we can't break blocks once
+ * mapped to tables.
+ * - MMIO: Unlike memory, pKVM allocates 1G for all MMIO, while
+ * the MMIO space can be large, as it is assumed to cover the
+ * whole IAS that is not memory, we have to use block mappings,
+ * that is fine for MMIO as it is never donated at the moment,
+ * so we never need to unmap MMIO at the run time triggering
+ * split block logic.
+ */
+ if (prot & IOMMU_MMIO)
+ pgsize = smmu_pgsize_idmap(size, start, pgtable->cfg.pgsize_bitmap);
+
+ pgcount = size / pgsize;
+ ret = pgtable->ops.map_pages(&pgtable->ops, start, start,
+ pgsize, pgcount, prot, 0, &mapped);
+ size -= mapped;
+ start += mapped;
+
+ if (ret == -EEXIST) {
+ /*
+ * It is possible to get EEXIST when a VM dies with pages
+ * in a shared state.
+ */
+ ret = 0;
+ size -= pgsize;
+ start += pgsize;
+ continue;
+ }
+ if (!mapped || ret)
+ break;
+ }
+ } else {
+ struct iommu_iotlb_gather gather;
+ size_t unmapped;
+
+ while (size) {
+ pgcount = size / pgsize;
+ iommu_iotlb_gather_init(&gather);
+ unmapped = pgtable->ops.unmap_pages(&pgtable->ops, start,
+ pgsize, pgcount, &gather);
+ size -= unmapped;
+ start += unmapped;
+ if (!unmapped)
+ break;
+ }
+ }
+
+ if (ret)
+ return ret;
+
+ if (WARN_ON(size))
+ return -EINVAL;
+
return 0;
}
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 23/25] iommu/arm-smmu-v3-kvm: Invalidate the SMMU TLBs
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (21 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 22/25] iommu/arm-smmu-v3-kvm: Shadow the CPU stage-2 page table Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 24/25] iommu/arm-smmu-v3-kvm: Enable nesting Mostafa Saleh
` (2 subsequent siblings)
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Implement the io-pgtable flush ops, which invalidate the shadow stage-2
in every SMMU.
Range invalidation algorithm is based on Robin suggestion on the list
for the upstream kernel driver, where a 2 overlapping commands can
invalidate any range.
Invalidation needs the command queue, so track whether it is enabled in
cmdq_active. It is updated with hw_lock held once the CR0 write has been
acknowledged, so it cannot change under a concurrent invalidation. For
the same reason the host is not allowed to disable the command queue
while the SMMU is enabled, as the hypervisor would no longer be able to
invalidate. As invalidation is skipped while the command queue is off,
flush the TLBs every time the SMMU is enabled.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
Jason is currently reworking the TLB invalidation on the mailing
list it might be possible to reuse some of the code once landed.
---
.../arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h | 2 +
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 177 +++++++++++++++++-
2 files changed, 176 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
index ffc57182e57e..534d329661cf 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3-hyp.h
@@ -29,6 +29,7 @@
* @cmdq_host Host view of the CMDQ, only q_base and llq used.
* @cmdq_max_shift Max shift for the CMDQ probed from HW.
* @cr0 Last value of CR0
+ * @cmdq_active Is SMMU HW cmdq usable, protected by hw_lock
* @host_ste_cfg Host stream table config
* @host_ste_base Host stream table base
* @strtab_cfg Stream table as seen by HW
@@ -57,6 +58,7 @@ struct hyp_arm_smmu_v3_device {
struct arm_smmu_queue cmdq_host;
u32 cmdq_max_shift;
u32 cr0;
+ bool cmdq_active;
dma_addr_t strtab_dma;
size_t strtab_size;
u64 host_ste_cfg;
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 6f0ea3a4e48d..5417a5c2bf58 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -207,7 +207,6 @@ static int smmu_sync_cmd(struct hyp_arm_smmu_v3_device *smmu)
smmu_cmdq_empty(&smmu->cmdq));
}
-__maybe_unused
static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
struct arm_smmu_cmd *cmd)
{
@@ -221,17 +220,139 @@ static int smmu_send_cmd(struct hyp_arm_smmu_v3_device *smmu,
return smmu_sync_cmd(smmu);
}
+static int smmu_tlb_inv_vmid(struct hyp_arm_smmu_v3_device *smmu)
+{
+ struct arm_smmu_cmd cmd = arm_smmu_make_cmd_op(CMDQ_OP_TLBI_S12_VMALL);
+
+ return smmu_send_cmd(smmu, &cmd);
+}
+
+static int smmu_tlb_range_inv_cmd(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmd *cmd,
+ unsigned long start, unsigned int num,
+ unsigned int scale, u8 ttl, bool leaf)
+{
+ size_t tg = __ffs(idmap_pgtable->cfg.pgsize_bitmap);
+ u8 tg_enc = arm_smmu_tlb_inv_tg_enc(tg);
+
+ cmd->data[0] |= arm_smmu_tlb_inv_range_enc(num, scale);
+ cmd->data[1] = arm_smmu_tlb_inv_addr(start, leaf, ttl, tg_enc);
+ return smmu_add_cmd(smmu, cmd);
+}
+
+static int __smmu_tlb_inv_range(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmd *cmd,
+ unsigned long iova, size_t size, size_t granule,
+ bool leaf)
+{
+ size_t tg = __ffs(idmap_pgtable->cfg.pgsize_bitmap);
+ unsigned long n = size >> tg;
+ unsigned long second_start;
+ u64 data0 = cmd->data[0];
+ unsigned int num, scale;
+ u8 ttl;
+ int ret;
+
+ /* Only leaf invalidations know the level, non-leaf must use TTL=0. */
+ ttl = leaf ? arm_smmu_tlb_inv_ttl(granule, tg) : 0;
+ scale = fls64((n - 1) / 32);
+ /* Scale is up to 5 bits. */
+ if (scale > 31)
+ return smmu_tlb_inv_vmid(smmu);
+
+ num = n >> scale;
+ ret = smmu_tlb_range_inv_cmd(smmu, cmd, iova, num, scale, ttl, leaf);
+ if (ret)
+ return ret;
+
+ n -= (unsigned long)num << scale;
+ if (n) {
+ scale = fls64((n - 1) / 32);
+ num = DIV_ROUND_UP(n, 1UL << scale);
+ second_start = iova + size - ((unsigned long)num << (scale + tg));
+
+ cmd->data[0] = data0;
+ ret = smmu_tlb_range_inv_cmd(smmu, cmd, second_start, num, scale, 0, leaf);
+ if (ret)
+ return ret;
+ }
+
+ return smmu_sync_cmd(smmu);
+}
+
+static int __smmu_tlb_inv_range_pages(struct hyp_arm_smmu_v3_device *smmu,
+ struct arm_smmu_cmd *cmd,
+ unsigned long iova, size_t size, size_t granule,
+ bool leaf)
+{
+ unsigned long end = iova + size;
+ int ret;
+
+ /* See arm_smmu_inv_size_too_big() */
+ if (size >= (1UL << (ilog2(granule) - 3)) * granule)
+ return smmu_tlb_inv_vmid(smmu);
+
+ for (; iova < end; iova += granule) {
+ cmd->data[1] = arm_smmu_tlb_inv_addr(iova, leaf, 0, 0);
+ ret = smmu_add_cmd(smmu, cmd);
+ if (ret)
+ return ret;
+ }
+
+ return smmu_sync_cmd(smmu);
+}
+
+static int smmu_tlb_inv_range_smmu(struct hyp_arm_smmu_v3_device *smmu,
+ unsigned long iova, size_t size, size_t granule,
+ bool leaf)
+{
+ struct arm_smmu_cmd cmd_s1 = arm_smmu_make_cmd_op(CMDQ_OP_TLBI_NH_ALL);
+ struct arm_smmu_cmd cmd = arm_smmu_make_cmd_op(CMDQ_OP_TLBI_S2_IPA);
+ int ret;
+
+ if (smmu->features & ARM_SMMU_FEAT_RANGE_INV)
+ ret = __smmu_tlb_inv_range(smmu, &cmd, iova, size, granule, leaf);
+ else
+ ret = __smmu_tlb_inv_range_pages(smmu, &cmd, iova, size, granule, leaf);
+ if (ret)
+ return ret;
+
+ return smmu_send_cmd(smmu, &cmd_s1);
+}
+
+static void smmu_tlb_inv_range(unsigned long iova, size_t size, size_t granule,
+ bool leaf)
+{
+ struct hyp_arm_smmu_v3_device *smmu;
+
+ for_each_smmu(smmu) {
+ hyp_spin_lock(&smmu->hw_lock);
+ /*
+ * Don't bother if CMDQ is disabled, this would be useful for the case
+ * when RPM is supported to avoid touching the SMMU MMIO when disabled.
+ * The hypervisor also asserts CMDQEN is enabled before the SMMU is
+ * enabled. As otherwise the host can prevent the hypervisor from doing
+ * TLB invalidations.
+ * When the SMMU is re-enabled the hypervisor cleans the TLBs.
+ */
+ if (smmu->cmdq_active)
+ WARN_ON(smmu_tlb_inv_range_smmu(smmu, iova, size,
+ granule, leaf));
+ hyp_spin_unlock(&smmu->hw_lock);
+ }
+}
+
static void smmu_tlb_flush_walk(unsigned long iova, size_t size,
size_t granule, void *cookie)
{
- /* TBD: Invalidate the range in all the SMMUs. */
+ smmu_tlb_inv_range(iova, size, granule, false);
}
static void smmu_tlb_add_page(struct iommu_iotlb_gather *gather,
unsigned long iova, size_t granule,
void *cookie)
{
- /* TBD: Invalidate the granule in all the SMMUs. */
+ smmu_tlb_inv_range(iova, granule, granule, true);
}
static const struct iommu_flush_ops smmu_tlb_ops = {
@@ -718,6 +839,33 @@ static int smmu_update_ste_shadow(struct hyp_arm_smmu_v3_device *smmu, bool enab
return smmu_unshare_pages(strtab_host_base(smmu), size);
}
+static int smmu_flush_all_tlb(struct hyp_arm_smmu_v3_device *smmu)
+{
+ int ret;
+ u32 cr0;
+ struct arm_smmu_cmd cmd = arm_smmu_make_cmd_op(CMDQ_OP_TLBI_NSNH_ALL);
+
+ hyp_spin_lock(&smmu->hw_lock);
+ /*
+ * This must be called when the SMMU is getting enabled.
+ * First enable the cmdq and then invalidate the TLB.
+ */
+ cr0 = readl_relaxed(smmu->base + ARM_SMMU_CR0);
+ if (!(cr0 & CR0_CMDQEN)) {
+ cr0 |= CR0_CMDQEN;
+ writel_relaxed(cr0, smmu->base + ARM_SMMU_CR0);
+ ret = smmu_wait(false, readl_relaxed(smmu->base + ARM_SMMU_CR0ACK) == cr0);
+ if (ret) {
+ hyp_spin_unlock(&smmu->hw_lock);
+ return ret;
+ }
+ }
+
+ ret = smmu_send_cmd(smmu, &cmd);
+ hyp_spin_unlock(&smmu->hw_lock);
+ return ret;
+}
+
static void smmu_emulate_enable(struct hyp_arm_smmu_v3_device *smmu)
{
/* Enabling SMMU without CMDQ, means TLB invalidation won't work. */
@@ -725,6 +873,8 @@ static void smmu_emulate_enable(struct hyp_arm_smmu_v3_device *smmu)
return;
WARN_ON(smmu_update_ste_shadow(smmu, true));
+ /* Clean the TLBs each time the SMMU is enabled. */
+ WARN_ON(smmu_flush_all_tlb(smmu));
}
static void smmu_emulate_disable(struct hyp_arm_smmu_v3_device *smmu)
@@ -745,6 +895,13 @@ static void smmu_emulate_cmdq_enable(struct hyp_arm_smmu_v3_device *smmu)
static void smmu_emulate_cmdq_disable(struct hyp_arm_smmu_v3_device *smmu)
{
+ /*
+ * We can not enable the SMMU if the CMDQ is disabled and similarly
+ * we can not disable the CMDQ if the SMMU is enabled, as that can
+ * lead to stale TLBs.
+ */
+ WARN_ON(is_smmu_enabled(smmu));
+
WARN_ON(smmu_unshare_pages(smmu->cmdq_host.base_dma,
cmdq_size(&smmu->cmdq_host)));
}
@@ -1020,6 +1177,20 @@ static bool smmu_dabt_device(struct hyp_arm_smmu_v3_device *smmu,
else
writel_relaxed(val & mask, smmu->base + off);
+ /*
+ * Make sure writes to CR0 are immediately observed, that is important
+ * when synchronizing with TLB invalidation as reading CR0 is not enough
+ * to deduce the SMMU state, and we have to enforce the ack with the
+ * hw_lock acquired.
+ */
+ if (off == ARM_SMMU_CR0) {
+ u32 cr0 = val;
+
+ WARN_ON(smmu_wait(false,
+ readl_relaxed(smmu->base + ARM_SMMU_CR0ACK) == cr0));
+ smmu->cmdq_active = !!(cr0 & CR0_CMDQEN);
+ }
+
hyp_spin_unlock(&smmu->hw_lock);
return true;
}
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 24/25] iommu/arm-smmu-v3-kvm: Enable nesting
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (22 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 23/25] iommu/arm-smmu-v3-kvm: Invalidate the SMMU TLBs Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 13:12 ` [PATCH v8 25/25] KVM: arm64: Add documentation for pKVM DMA isolation Mostafa Saleh
2026-09-22 18:07 ` [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Nicolin Chen
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
As now the hypervisor controls the command queue, stream table,
and shadows the stage-2 page table, we enable stage-2 translation
in case the host puts an STE in bypass or stage-1.
The hypervisor will control the S2 part of the STE and sanitize it.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
.../iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c | 109 +++++++++++++++++-
1 file changed, 103 insertions(+), 6 deletions(-)
diff --git a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
index 5417a5c2bf58..39c97404e039 100644
--- a/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/pkvm/arm-smmu-v3.c
@@ -461,6 +461,57 @@ static int smmu_init_cmdq(struct hyp_arm_smmu_v3_device *smmu)
return 0;
}
+static int smmu_attach_stage_2(struct arm_smmu_ste *ste)
+{
+ unsigned long vttbr, cfg;
+ unsigned long ts, sl, ic, oc, sh, tg, ps;
+ struct io_pgtable_cfg *pgt_cfg = &idmap_pgtable->cfg;
+
+ cfg = FIELD_GET(STRTAB_STE_0_CFG, le64_to_cpu(ste->data[0]));
+ if (!FIELD_GET(STRTAB_STE_0_V, le64_to_cpu(ste->data[0])) ||
+ (cfg == STRTAB_STE_0_CFG_ABORT)) {
+ return 0;
+ }
+ /* S2 is not advertised, that should never be attempted. */
+ if ((cfg == STRTAB_STE_0_CFG_S2_TRANS) ||
+ (cfg == STRTAB_STE_0_CFG_NESTED))
+ return -EINVAL;
+ vttbr = pgt_cfg->arm_lpae_s2_cfg.vttbr;
+ ps = pgt_cfg->arm_lpae_s2_cfg.vtcr.ps;
+ tg = pgt_cfg->arm_lpae_s2_cfg.vtcr.tg;
+ sh = pgt_cfg->arm_lpae_s2_cfg.vtcr.sh;
+ oc = pgt_cfg->arm_lpae_s2_cfg.vtcr.orgn;
+ ic = pgt_cfg->arm_lpae_s2_cfg.vtcr.irgn;
+ sl = pgt_cfg->arm_lpae_s2_cfg.vtcr.sl;
+ ts = pgt_cfg->arm_lpae_s2_cfg.vtcr.tsz;
+
+ ste->data[1] &= ~cpu_to_le64(STRTAB_STE_1_SHCFG);
+ ste->data[1] |= cpu_to_le64(FIELD_PREP(STRTAB_STE_1_SHCFG, STRTAB_STE_1_SHCFG_INCOMING));
+
+ ste->data[1] &= ~cpu_to_le64(STRTAB_STE_1_EATS | STRTAB_STE_1_S2FWB | STRTAB_STE_1_STRW);
+
+ /* The host shouldn't write dwords 2 and 3, overwrite them. */
+ ste->data[2] = cpu_to_le64(FIELD_PREP(STRTAB_STE_2_VTCR,
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2PS, ps) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2TG, tg) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2SH0, sh) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2OR0, oc) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2IR0, ic) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2SL0, sl) |
+ FIELD_PREP(STRTAB_STE_2_VTCR_S2T0SZ, ts)) |
+ FIELD_PREP(STRTAB_STE_2_S2VMID, 0) |
+ STRTAB_STE_2_S2AA64 | STRTAB_STE_2_S2R |
+#ifdef __BIG_ENDIAN
+ STRTAB_STE_2_S2ENDI |
+#endif
+ STRTAB_STE_2_S2PTW);
+
+ ste->data[3] = cpu_to_le64(vttbr & STRTAB_STE_3_S2TTB_MASK);
+ /* Convert S1 => nested and bypass => S2 */
+ ste->data[0] |= cpu_to_le64(FIELD_PREP(STRTAB_STE_0_CFG, cfg | BIT(1)));
+ return 0;
+}
+
static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
struct arm_smmu_ste *host_ste_out)
{
@@ -490,12 +541,40 @@ static int smmu_get_host_l2_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid,
return 0;
}
+struct smmu_ste_writer {
+ struct arm_smmu_entry_writer writer;
+ struct hyp_arm_smmu_v3_device *smmu;
+ u32 sid;
+};
+
+static void smmu_ste_writer_sync_entry(struct arm_smmu_entry_writer *writer)
+{
+ struct smmu_ste_writer *ste_writer =
+ container_of(writer, struct smmu_ste_writer, writer);
+ struct arm_smmu_cmd cfgi_cmd = arm_smmu_make_cmd_cfgi_ste(ste_writer->sid, true);
+
+ WARN_ON(smmu_send_cmd(ste_writer->smmu, &cfgi_cmd));
+}
+
+static const struct arm_smmu_entry_writer_ops smmu_ste_writer_ops = {
+ .get_used = arm_smmu_get_ste_used,
+ .get_update_safe = arm_smmu_get_ste_update_safe,
+ .sync = smmu_ste_writer_sync_entry,
+};
+
static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool leaf)
{
struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
- struct arm_smmu_ste *hyp_ste_ptr, *host_ste_ptr, host_ste_copy;
+ struct arm_smmu_ste *hyp_ste_ptr;
u64 *hyp_ste_base = strtab_hyp_base(smmu);
+ __le64 used[STRTAB_STE_DWORDS] = {};
+ struct arm_smmu_ste target = {};
int ret, i;
+ struct smmu_ste_writer ste_writer = {
+ .writer.ops = &smmu_ste_writer_ops,
+ .smmu = smmu,
+ .sid = sid,
+ };
/* Leaf = 0 is not supported, as the kernel driver. */
if (!leaf || !is_smmu_enabled(smmu) ||
@@ -511,7 +590,7 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
return -E2BIG;
hyp_ste_ptr = &hyp_table[sid];
- host_ste_ptr = &host_table[sid];
+ memcpy(target.data, host_table[sid].data, STRTAB_STE_DWORDS << 3);
} else {
struct arm_smmu_strtab_l1 *l1tab = (struct arm_smmu_strtab_l1 *)hyp_ste_base;
u32 l1_idx = arm_smmu_strtab_l1_idx(sid);
@@ -520,8 +599,7 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
if (l1_idx >= cfg->l2.num_l1_ents)
return -E2BIG;
- host_ste_ptr = &host_ste_copy;
- ret = smmu_get_host_l2_ste(smmu, sid, host_ste_ptr);
+ ret = smmu_get_host_l2_ste(smmu, sid, &target);
if (ret)
return ret;
@@ -541,8 +619,27 @@ static int smmu_reshadow_ste(struct hyp_arm_smmu_v3_device *smmu, u32 sid, bool
hyp_ste_ptr = &l2ptr->stes[arm_smmu_strtab_l2_idx(sid)];
}
- for (i = 0; i < STRTAB_STE_DWORDS; ++i)
- WRITE_ONCE(hyp_ste_ptr->data[i], host_ste_ptr->data[i]);
+ /*
+ * Summary of each host emulated state vs real HW.
+ * | Host | HW |
+ * ==============================
+ * | V=0 | V=0 |
+ * | Abort | Abort |
+ * | Bypass | S2 |
+ * | S1 | S1+S2 |
+ */
+ ret = smmu_attach_stage_2(&target);
+ if (ret)
+ return ret;
+
+ /* The HW ignores unused fields, don't let the host set them. */
+ arm_smmu_get_ste_used(target.data, used);
+ for (i = 0; i < STRTAB_STE_DWORDS; i++)
+ target.data[i] &= used[i];
+
+ hyp_spin_lock(&smmu->hw_lock);
+ arm_smmu_write_entry(&ste_writer.writer, hyp_ste_ptr->data, target.data);
+ hyp_spin_unlock(&smmu->hw_lock);
return 0;
}
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* [PATCH v8 25/25] KVM: arm64: Add documentation for pKVM DMA isolation
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (23 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 24/25] iommu/arm-smmu-v3-kvm: Enable nesting Mostafa Saleh
@ 2026-09-22 13:12 ` Mostafa Saleh
2026-09-22 18:07 ` [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Nicolin Chen
25 siblings, 0 replies; 31+ messages in thread
From: Mostafa Saleh @ 2026-09-22 13:12 UTC (permalink / raw)
To: linux-arm-kernel, linux-kernel, kvmarm, iommu
Cc: catalin.marinas, will, maz, oliver.upton, joey.gouly,
suzuki.poulose, yuzenghui, joro, jgg, mark.rutland, qperret,
tabba, vdonnefort, sebastianene, keirf, Mostafa Saleh
Populate the section for DMA isolation in pKVM with the newly
added KVM IOMMU and pKVM SMMUv3 driver details.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
---
Documentation/virt/kvm/arm/pkvm.rst | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/Documentation/virt/kvm/arm/pkvm.rst b/Documentation/virt/kvm/arm/pkvm.rst
index 514992a79a83..ce67e2ae1f9a 100644
--- a/Documentation/virt/kvm/arm/pkvm.rst
+++ b/Documentation/virt/kvm/arm/pkvm.rst
@@ -77,7 +77,28 @@ Status: **Unimplemented.**
DMA isolation using an IOMMU
----------------------------
-Status: **Unimplemented.**
+Status: Supported for devices behind SMMUv3 supporting dual stages
+of translation.
+
+With ``CONFIG_ARM_SMMU_V3_PKVM``, the hypervisor will take over the SMMUs
+on the system and provide an architectural emulation to the kernel SMMUv3
+driver.
+
+If some devices are not behind an IOMMU or behind another IOMMU architecture,
+DMA isolation is not supported, as a driver must be provided for that.
+
+DMA isolation is enforced by dual stages of translation; similar to the CPU
+where a driver can register their ops through ``kvm_iommu_register_driver``
+and implement ``host_stage2_idmap`` to shadow the CPU page table.
+
+The page tables for the stage-2 SMMUv3 will be allocated from a pool created
+at boot with size configured from the command line "kvm-arm.iommu_pgt_mem"
+The size must cover the worst case scenario for leaf mappings of system memory.
+
+This implementation trusts the system firmware not to allow the untrusted
+host kernel to bypass the SMMUv3.
+For example, by resetting the power. In that case, it is the firmware's
+responsibility to save/restore the SMMUv3 state.
Proxying of Trustzone services
------------------------------
--
2.55.0.1082.g2b9226bbc0-goog
^ permalink raw reply [flat|nested] 31+ messages in thread* Re: [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate)
2026-09-22 13:12 [PATCH v8 00/25] KVM: arm64: SMMUv3 driver for pKVM (trap and emulate) Mostafa Saleh
` (24 preceding siblings ...)
2026-09-22 13:12 ` [PATCH v8 25/25] KVM: arm64: Add documentation for pKVM DMA isolation Mostafa Saleh
@ 2026-09-22 18:07 ` Nicolin Chen
25 siblings, 0 replies; 31+ messages in thread
From: Nicolin Chen @ 2026-09-22 18:07 UTC (permalink / raw)
To: Mostafa Saleh
Cc: linux-arm-kernel, linux-kernel, kvmarm, iommu, catalin.marinas,
will, maz, oliver.upton, joey.gouly, suzuki.poulose, yuzenghui,
joro, jgg, mark.rutland, qperret, tabba, vdonnefort,
sebastianene, keirf
On Tue, Sep 22, 2026 at 01:12:33PM +0000, Mostafa Saleh wrote:
> Notes about Sashiko
> ===================
> I ran Sashiko locally and it was helpful in discovering problems in
> the series. However, it still shows large number of critical and high
> severity issues, I went through them and I believe they are false
> positives, mainly because (in the order of frequently reported):
> - It doesn't understand WARNs are fatal in the hypervisor.
> - It doesn't understand that a malicious host can DoS the system and
> pKVM doesn't guarantee availability
> - It doesn't understand the SMMUv3 spec and makes stuff up (eg. about
> CMD_SYC CS field it makes up an non-existent encoding or wrong
> semantics for the gbpa register)
Just my two cents here:
From my experience, making commit messages or inline notes slightly
clearer against the findings that Sashiko reported could simply help
it understand things better and mute most of the false positives.
Otherwise, the number of the findings is a bit scaring; reviewers
would have to go through the long list of findings to check whether
each of them fits into one of the false-positive categories :-/
> - It seems to look at one patch at a time and not the whole series, and
> as the series is written in a way to be bisectable that confuses it.
Yea, that happens too. Usually I would add a line at the end of the
commit message "a subsequent change will do X", which could clarify.
Nicolin
^ permalink raw reply [flat|nested] 31+ messages in thread