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authorMarc Zyngier <maz@kernel.org>2023-05-11 17:26:01 +0300
committerMarc Zyngier <maz@kernel.org>2023-05-11 17:26:01 +0300
commitc3a62df457ff9ac8c77efe6d1eca2855d399355d (patch)
treeaeed6dcc72dfcd76800481a2fe355b8cc532ebe3 /arch
parent9a48c597d60decb1c1f982a9eac19519dbf02875 (diff)
parent1ea244158a4a20ac686f4d1d46285f3d38d4571f (diff)
downloadlinux-c3a62df457ff9ac8c77efe6d1eca2855d399355d.tar.xz
Merge branch kvm-arm64/pgtable-fixes-6.4 into kvmarm-master/fixes
* kvm-arm64/pgtable-fixes-6.4: : . : Fixes for concurrent S2 mapping race from Oliver: : : "So it appears that there is a race between two parallel stage-2 map : walkers that could lead to mapping the incorrect PA for a given IPA, as : the IPA -> PA relationship picks up an unintended offset. This series : eliminates the problem by using the current IPA of the walk as the : source-of-truth regarding where we are in a map operation." : . KVM: arm64: Constify start/end/phys fields of the pgtable walker data KVM: arm64: Infer PA offset from VA in hyp map walker KVM: arm64: Infer the PA offset from IPA in stage-2 map walker Signed-off-by: Marc Zyngier <maz@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/kvm_pgtable.h1
-rw-r--r--arch/arm64/kvm/hyp/pgtable.c41
2 files changed, 33 insertions, 9 deletions
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
index 4cd6762bda80..dc3c072e862f 100644
--- a/arch/arm64/include/asm/kvm_pgtable.h
+++ b/arch/arm64/include/asm/kvm_pgtable.h
@@ -209,6 +209,7 @@ struct kvm_pgtable_visit_ctx {
kvm_pte_t old;
void *arg;
struct kvm_pgtable_mm_ops *mm_ops;
+ u64 start;
u64 addr;
u64 end;
u32 level;
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 3d61bd3e591d..5282cb9ca4cf 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -58,8 +58,9 @@
struct kvm_pgtable_walk_data {
struct kvm_pgtable_walker *walker;
+ const u64 start;
u64 addr;
- u64 end;
+ const u64 end;
};
static bool kvm_phys_is_valid(u64 phys)
@@ -201,6 +202,7 @@ static inline int __kvm_pgtable_visit(struct kvm_pgtable_walk_data *data,
.old = READ_ONCE(*ptep),
.arg = data->walker->arg,
.mm_ops = mm_ops,
+ .start = data->start,
.addr = data->addr,
.end = data->end,
.level = level,
@@ -293,6 +295,7 @@ int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size,
struct kvm_pgtable_walker *walker)
{
struct kvm_pgtable_walk_data walk_data = {
+ .start = ALIGN_DOWN(addr, PAGE_SIZE),
.addr = ALIGN_DOWN(addr, PAGE_SIZE),
.end = PAGE_ALIGN(walk_data.addr + size),
.walker = walker,
@@ -349,7 +352,7 @@ int kvm_pgtable_get_leaf(struct kvm_pgtable *pgt, u64 addr,
}
struct hyp_map_data {
- u64 phys;
+ const u64 phys;
kvm_pte_t attr;
};
@@ -407,13 +410,12 @@ enum kvm_pgtable_prot kvm_pgtable_hyp_pte_prot(kvm_pte_t pte)
static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
struct hyp_map_data *data)
{
+ u64 phys = data->phys + (ctx->addr - ctx->start);
kvm_pte_t new;
- u64 granule = kvm_granule_size(ctx->level), phys = data->phys;
if (!kvm_block_mapping_supported(ctx, phys))
return false;
- data->phys += granule;
new = kvm_init_valid_leaf_pte(phys, data->attr, ctx->level);
if (ctx->old == new)
return true;
@@ -576,7 +578,7 @@ void kvm_pgtable_hyp_destroy(struct kvm_pgtable *pgt)
}
struct stage2_map_data {
- u64 phys;
+ const u64 phys;
kvm_pte_t attr;
u8 owner_id;
@@ -794,20 +796,43 @@ static bool stage2_pte_executable(kvm_pte_t pte)
return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
}
+static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,
+ const struct stage2_map_data *data)
+{
+ u64 phys = data->phys;
+
+ /*
+ * Stage-2 walks to update ownership data are communicated to the map
+ * walker using an invalid PA. Avoid offsetting an already invalid PA,
+ * which could overflow and make the address valid again.
+ */
+ if (!kvm_phys_is_valid(phys))
+ return phys;
+
+ /*
+ * Otherwise, work out the correct PA based on how far the walk has
+ * gotten.
+ */
+ return phys + (ctx->addr - ctx->start);
+}
+
static bool stage2_leaf_mapping_allowed(const struct kvm_pgtable_visit_ctx *ctx,
struct stage2_map_data *data)
{
+ u64 phys = stage2_map_walker_phys_addr(ctx, data);
+
if (data->force_pte && (ctx->level < (KVM_PGTABLE_MAX_LEVELS - 1)))
return false;
- return kvm_block_mapping_supported(ctx, data->phys);
+ return kvm_block_mapping_supported(ctx, phys);
}
static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
struct stage2_map_data *data)
{
kvm_pte_t new;
- u64 granule = kvm_granule_size(ctx->level), phys = data->phys;
+ u64 phys = stage2_map_walker_phys_addr(ctx, data);
+ u64 granule = kvm_granule_size(ctx->level);
struct kvm_pgtable *pgt = data->mmu->pgt;
struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
@@ -841,8 +866,6 @@ static int stage2_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
stage2_make_pte(ctx, new);
- if (kvm_phys_is_valid(phys))
- data->phys += granule;
return 0;
}