[RFC PATCH v2 50/58] iommu/arm-smmu-v3-kvm: Add map, unmap and iova_to_phys operations

[Mostafa Saleh <smostafa@google.com>]

Add map, unmap and iova_to_phys, which are forwarded to the
hypervisor.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 .../iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c   | 72 +++++++++++++++++++
 1 file changed, 72 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 071743f5acf9..82f0191b222c 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
@@ -331,6 +331,75 @@ static bool kvm_arm_smmu_capable(struct device *dev, enum iommu_cap cap)
 	}
 }
 
+static int kvm_arm_smmu_map_pages(struct iommu_domain *domain,
+				  unsigned long iova, phys_addr_t paddr,
+				  size_t pgsize, size_t pgcount, int prot,
+				  gfp_t gfp, size_t *total_mapped)
+{
+	size_t mapped;
+	size_t size = pgsize * pgcount;
+	struct kvm_arm_smmu_domain *kvm_smmu_domain = to_kvm_smmu_domain(domain);
+	struct arm_smccc_res res;
+
+	do {
+		res = kvm_call_hyp_nvhe_smccc(__pkvm_host_iommu_map_pages,
+					      kvm_smmu_domain->id,
+					      iova, paddr, pgsize, pgcount, prot);
+		mapped = res.a1;
+		iova += mapped;
+		paddr += mapped;
+		WARN_ON(mapped % pgsize);
+		WARN_ON(mapped > pgcount * pgsize);
+		pgcount -= mapped / pgsize;
+		*total_mapped += mapped;
+	} while (*total_mapped < size && !kvm_arm_smmu_topup_memcache(&res, gfp));
+	if (*total_mapped < size)
+		return -EINVAL;
+
+	return 0;
+}
+
+static size_t kvm_arm_smmu_unmap_pages(struct iommu_domain *domain,
+				       unsigned long iova, size_t pgsize,
+				       size_t pgcount,
+				       struct iommu_iotlb_gather *iotlb_gather)
+{
+	size_t unmapped;
+	size_t total_unmapped = 0;
+	size_t size = pgsize * pgcount;
+	struct kvm_arm_smmu_domain *kvm_smmu_domain = to_kvm_smmu_domain(domain);
+	struct arm_smccc_res res;
+
+	do {
+		res = kvm_call_hyp_nvhe_smccc(__pkvm_host_iommu_unmap_pages,
+					      kvm_smmu_domain->id,
+					      iova, pgsize, pgcount);
+		unmapped = res.a1;
+		total_unmapped += unmapped;
+		iova += unmapped;
+		WARN_ON(unmapped % pgsize);
+		pgcount -= unmapped / pgsize;
+
+		/*
+		 * The page table driver can unmap less than we asked for. If it
+		 * didn't unmap anything at all, then it either reached the end
+		 * of the range, or it needs a page in the memcache to break a
+		 * block mapping.
+		 */
+	} while (total_unmapped < size &&
+		 (unmapped || !kvm_arm_smmu_topup_memcache(&res, GFP_ATOMIC)));
+
+	return total_unmapped;
+}
+
+static phys_addr_t kvm_arm_smmu_iova_to_phys(struct iommu_domain *domain,
+					     dma_addr_t iova)
+{
+	struct kvm_arm_smmu_domain *kvm_smmu_domain = to_kvm_smmu_domain(domain);
+
+	return kvm_call_hyp_nvhe(__pkvm_host_iommu_iova_to_phys, kvm_smmu_domain->id, iova);
+}
+
 static struct iommu_ops kvm_arm_smmu_ops = {
 	.capable		= kvm_arm_smmu_capable,
 	.device_group		= arm_smmu_device_group,
@@ -344,6 +413,9 @@ static struct iommu_ops kvm_arm_smmu_ops = {
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= kvm_arm_smmu_attach_dev,
 		.free		= kvm_arm_smmu_domain_free,
+		.map_pages	= kvm_arm_smmu_map_pages,
+		.unmap_pages	= kvm_arm_smmu_unmap_pages,
+		.iova_to_phys	= kvm_arm_smmu_iova_to_phys,
 	}
 };
 
-- 
2.47.0.338.g60cca15819-goog