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ANDROID: iommu/iommu: Handle multi-page deferred sg mappings

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The `__iommu_add_sg` function currently assumes that a scatter-gather
entry will always map to a single page size. However, a single
scatter-gather entry can span multiple IOMMU page sizes if there is
a larger page size mapping. This can lead to issues with deferred
scatter-gather mappings.

This patch modifies `__iommu_add_sg` to iteratively call
`ops->add_deferred_map_sg` for each IOMMU page-sized chunk within a
scatter-gather entry, ensuring that all parts of the entry are
correctly handled for deferred mappings.

Fixes: 1a608d2b0d ("BACKPORT: FROMLIST: drivers/iommu: Add deferred map_sg operations")
Change-Id: I2d2edbd5fa3d37c0b1e4a9976824b77a9ef39676
Signed-off-by: Ryan Huang <tzukui@google.com>
Signed-off-by: Mostafa Saleh <smostafa@google.com>
This commit is contained in:
Ryan Huang
2025-06-17 13:52:58 -07:00
committed by Mostafa Saleh
parent 740d42d181
commit 672185e575
3 changed files with 48 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
arch/arm64/include/asm/kvm_host.h
View File

@@ -1747,14 +1747,22 @@ struct kvm_iommu_sg {
unsigned int pgcount;
};
#define kvm_iommu_sg_nents_size(n) (PAGE_ALIGN((n) * sizeof(struct kvm_iommu_sg)))
static inline unsigned int kvm_iommu_sg_nents_round(unsigned int nents)
{
return kvm_iommu_sg_nents_size(nents) / sizeof(struct kvm_iommu_sg);
}
static inline struct kvm_iommu_sg *kvm_iommu_sg_alloc(unsigned int nents, gfp_t gfp)
{
return alloc_pages_exact(PAGE_ALIGN(nents * sizeof(struct kvm_iommu_sg)), gfp);
return alloc_pages_exact(kvm_iommu_sg_nents_size(nents), gfp);
}
static inline void kvm_iommu_sg_free(struct kvm_iommu_sg *sg, unsigned int nents)
{
free_pages_exact(sg, PAGE_ALIGN(nents * sizeof(struct kvm_iommu_sg)));
free_pages_exact(sg, kvm_iommu_sg_nents_size(nents));
}

28
drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-kvm.c
View File

@@ -411,6 +411,7 @@ struct kvm_arm_smmu_map_sg {
int prot;
gfp_t gfp;
unsigned int nents;
size_t total_mapped;
};
static struct iommu_map_cookie_sg *kvm_arm_smmu_alloc_cookie_sg(unsigned long iova,
@@ -424,16 +425,17 @@ static struct iommu_map_cookie_sg *kvm_arm_smmu_alloc_cookie_sg(unsigned long io
if (!map_sg)
return NULL;
map_sg->sg = kvm_iommu_sg_alloc(nents, gfp);
/* Rounds nents to allocate to page aligned size. */
map_sg->nents = kvm_iommu_sg_nents_round(nents);
map_sg->sg = kvm_iommu_sg_alloc(map_sg->nents, gfp);
if (!map_sg->sg)
return NULL;
map_sg->iova = iova;
map_sg->prot = prot;
map_sg->gfp = gfp;
map_sg->nents = nents;
ret = kvm_iommu_share_hyp_sg(map_sg->sg, nents);
ret = kvm_iommu_share_hyp_sg(map_sg->sg, map_sg->nents);
if (ret) {
kvm_iommu_sg_free(map_sg->sg, nents);
kvm_iommu_sg_free(map_sg->sg, map_sg->nents);
kfree(map_sg);
return NULL;
}
@@ -447,6 +449,17 @@ static int kvm_arm_smmu_add_deferred_map_sg(struct iommu_map_cookie_sg *cookie,
struct kvm_arm_smmu_map_sg *map_sg = container_of(cookie, struct kvm_arm_smmu_map_sg,
cookie);
struct kvm_iommu_sg *sg = map_sg->sg;
struct kvm_arm_smmu_domain *kvm_smmu_domain = to_kvm_smmu_domain(map_sg->cookie.domain);
size_t mapped;
/* Out of space, flush the list. */
if (map_sg->nents == map_sg->ptr) {
mapped = kvm_iommu_map_sg(kvm_smmu_domain->id, sg, map_sg->iova,
map_sg->ptr, map_sg->prot, map_sg->gfp);
map_sg->ptr = 0;
map_sg->iova += mapped;
map_sg->total_mapped += mapped;
}
sg[map_sg->ptr].phys = paddr;
sg[map_sg->ptr].pgsize = pgsize;
@@ -461,11 +474,10 @@ static size_t kvm_arm_smmu_consume_deferred_map_sg(struct iommu_map_cookie_sg *c
cookie);
struct kvm_iommu_sg *sg = map_sg->sg;
struct kvm_arm_smmu_domain *kvm_smmu_domain = to_kvm_smmu_domain(map_sg->cookie.domain);
size_t total_mapped;
total_mapped = kvm_iommu_map_sg(kvm_smmu_domain->id, sg, map_sg->iova, map_sg->ptr,
map_sg->prot, map_sg->gfp);
size_t total_mapped = map_sg->total_mapped;
total_mapped += kvm_iommu_map_sg(kvm_smmu_domain->id, sg, map_sg->iova,
map_sg->ptr, map_sg->prot, map_sg->gfp);
kvm_iommu_unshare_hyp_sg(sg, map_sg->nents);
kvm_iommu_sg_free(sg, map_sg->nents);
kfree(map_sg);

22
drivers/iommu/iommu.c
View File

@@ -2638,7 +2638,7 @@ static int __iommu_add_sg(struct iommu_map_cookie_sg *cookie_sg,
struct iommu_domain *domain = cookie_sg->domain;
const struct iommu_domain_ops *ops = domain->ops;
unsigned int min_pagesz;
size_t pgsize, count;
int ret = 0;
if (unlikely(!(domain->type & __IOMMU_DOMAIN_PAGING)))
return -EINVAL;
@@ -2659,8 +2659,22 @@ static int __iommu_add_sg(struct iommu_map_cookie_sg *cookie_sg,
iova, &paddr, size, min_pagesz);
return -EINVAL;
}
pgsize = iommu_pgsize(domain, iova, paddr, size, &count);
return ops->add_deferred_map_sg(cookie_sg, paddr, pgsize, count);
while (size) {
size_t pgsize, count, added;
pgsize = iommu_pgsize(domain, iova, paddr, size, &count);
ret = ops->add_deferred_map_sg(cookie_sg, paddr, pgsize, count);
if (ret)
break;
added = pgsize * count;
size -= added;
iova += added;
paddr += added;
}
return ret;
}
ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
@@ -2720,7 +2734,7 @@ next:
size_t consumed;
consumed = ops->consume_deferred_map_sg(cookie_sg);
if (consumed != mapped) {
if (WARN_ON(consumed != mapped)) {
mapped = consumed;
ret = -EINVAL;
goto out_err;