[PATCH v4 3/3] iommu/amd: Adhere to IVINFO[VASIZE] for address limits

[Ankit Soni <Ankit.Soni@amd.com>]

ACPI IVRS IVHD’s IVINFO field reports the maximum virtual address
size (VASIZE) supported by the IOMMU. The AMD IOMMU driver currently
caps this with pagetable level reported by EFR[HATS] when configuring
paging domains (hw_max_vasz_lg2). On systems where firmware or VM
advertises smaller or different limits, the driver may over-advertise
capabilities and create domains outside the hardware’s actual bounds.

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Ankit Soni <Ankit.Soni@amd.com>
---
 drivers/iommu/amd/amd_iommu.h       |  2 +-
 drivers/iommu/amd/amd_iommu_types.h |  1 +
 drivers/iommu/amd/init.c            | 13 +++++++++----
 drivers/iommu/amd/iommu.c           |  3 +--
 4 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu.h b/drivers/iommu/amd/amd_iommu.h
index 1342e764a548..f915938a3a08 100644
--- a/drivers/iommu/amd/amd_iommu.h
+++ b/drivers/iommu/amd/amd_iommu.h
@@ -41,7 +41,7 @@ int amd_iommu_enable_faulting(unsigned int cpu);
 extern int amd_iommu_guest_ir;
 extern enum protection_domain_mode amd_iommu_pgtable;
 extern int amd_iommu_gpt_level;
-extern u8 amd_iommu_hpt_level;
+extern u8 amd_iommu_hpt_vasize;
 extern unsigned long amd_iommu_pgsize_bitmap;
 extern bool amd_iommu_hatdis;
 
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index c685d3771436..6a85a38d34bd 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -395,6 +395,7 @@
 #define IOMMU_IVINFO_OFFSET     36
 #define IOMMU_IVINFO_EFRSUP     BIT(0)
 #define IOMMU_IVINFO_DMA_REMAP  BIT(1)
+#define IOMMU_IVINFO_VASIZE	GENMASK_ULL(21, 15)
 
 /* IOMMU Feature Reporting Field (for IVHD type 10h */
 #define IOMMU_FEAT_GASUP_SHIFT	6
diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index f3fd7f39efb4..e874a4135d5c 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -152,8 +152,8 @@ bool amd_iommu_dump;
 bool amd_iommu_irq_remap __read_mostly;
 
 enum protection_domain_mode amd_iommu_pgtable = PD_MODE_V1;
-/* Host page table level */
-u8 amd_iommu_hpt_level;
+/* Virtual address size */
+u8 amd_iommu_hpt_vasize;
 /* Guest page table level */
 int amd_iommu_gpt_level = PAGE_MODE_4_LEVEL;
 
@@ -3188,7 +3188,7 @@ static int __init early_amd_iommu_init(void)
 	struct acpi_table_header *ivrs_base;
 	int ret;
 	acpi_status status;
-	u8 efr_hats;
+	u8 efr_hats, max_vasize;
 
 	if (!amd_iommu_detected)
 		return -ENODEV;
@@ -3218,6 +3218,10 @@ static int __init early_amd_iommu_init(void)
 
 	ivinfo_init(ivrs_base);
 
+	max_vasize = FIELD_GET(IOMMU_IVINFO_VASIZE, amd_iommu_ivinfo);
+	if (!max_vasize)
+		max_vasize = 64;
+
 	amd_iommu_target_ivhd_type = get_highest_supported_ivhd_type(ivrs_base);
 	DUMP_printk("Using IVHD type %#x\n", amd_iommu_target_ivhd_type);
 
@@ -3240,7 +3244,8 @@ static int __init early_amd_iommu_init(void)
 		 * efr[HATS] bits specify the maximum host translation level
 		 * supported, with LEVEL 4 being initial max level.
 		 */
-		amd_iommu_hpt_level = efr_hats + PAGE_MODE_4_LEVEL;
+		amd_iommu_hpt_vasize = min_t(unsigned int, max_vasize,
+					 (efr_hats + PAGE_MODE_4_LEVEL - 1) * 9 + 21);
 	} else {
 		pr_warn_once(FW_BUG "Disable host address translation due to invalid translation level (%#x).\n",
 			     efr_hats);
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 760d5f4623b5..c18252a2c857 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2712,8 +2712,7 @@ static struct iommu_domain *amd_iommu_domain_alloc_paging_v1(struct device *dev,
 	else
 		cfg.common.features |= BIT(PT_FEAT_FLUSH_RANGE);
 
-	cfg.common.hw_max_vasz_lg2 =
-		min(64, (amd_iommu_hpt_level - 1) * 9 + 21);
+	cfg.common.hw_max_vasz_lg2 = amd_iommu_hpt_vasize;
 	cfg.common.hw_max_oasz_lg2 = 52;
 	cfg.starting_level = 2;
 	domain->domain.ops = &amdv1_ops;
-- 
2.43.0