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[ciqlts9_2] Multiple patches tested (2 commits) #1408

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Merged
PlaidCat merged 2 commits into from
Jul 6, 2026
+18 −24
Merged

[ciqlts9_2] Multiple patches tested (2 commits) #1408

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f6b15e7
KVM: x86: Fix shadow paging use-after-free due to unexpected GFN
sean-jc Apr 15, 2026
c9fe36b
KVM: x86: Fix shadow paging use-after-free due to unexpected role
bonzini Jun 12, 2026
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42 changes: 18 additions & 24 deletions arch/x86/kvm/mmu/mmu.c
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Original file line number Diff line number Diff line change
Expand Up @@ -167,6 +167,8 @@ struct kmem_cache *mmu_page_header_cache;
static struct percpu_counter kvm_total_used_mmu_pages;

static void mmu_spte_set(u64 *sptep, u64 spte);
static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
u64 *spte, struct list_head *invalid_list);

struct kvm_mmu_role_regs {
const unsigned long cr0;
Expand Down Expand Up @@ -1146,20 +1148,6 @@ static void drop_spte(struct kvm *kvm, u64 *sptep)
rmap_remove(kvm, sptep);
}

static void drop_large_spte(struct kvm *kvm, u64 *sptep, bool flush)
{
struct kvm_mmu_page *sp;

sp = sptep_to_sp(sptep);
WARN_ON(sp->role.level == PG_LEVEL_4K);

drop_spte(kvm, sptep);

if (flush)
kvm_flush_remote_tlbs_with_address(kvm, sp->gfn,
KVM_PAGES_PER_HPAGE(sp->role.level));
}

/*
* Write-protect on the specified @sptep, @pt_protect indicates whether
* spte write-protection is caused by protecting shadow page table.
Expand Down Expand Up @@ -2229,12 +2217,15 @@ static struct kvm_mmu_page *kvm_mmu_get_child_sp(struct kvm_vcpu *vcpu,
u64 *sptep, gfn_t gfn,
bool direct, unsigned int access)
{
union kvm_mmu_page_role role;
union kvm_mmu_page_role role = kvm_mmu_child_role(sptep, direct, access);

if (is_shadow_present_pte(*sptep) && !is_large_pte(*sptep))
if (is_shadow_present_pte(*sptep) &&
!is_large_pte(*sptep) &&
to_shadow_page(*sptep & SPTE_BASE_ADDR_MASK) &&
to_shadow_page(*sptep & SPTE_BASE_ADDR_MASK)->gfn == gfn &&
to_shadow_page(*sptep & SPTE_BASE_ADDR_MASK)->role.word == role.word)
return ERR_PTR(-EEXIST);

role = kvm_mmu_child_role(sptep, direct, access);
return kvm_mmu_get_shadow_page(vcpu, gfn, role);
}

Expand Down Expand Up @@ -2309,13 +2300,16 @@ static void __link_shadow_page(struct kvm *kvm,

BUILD_BUG_ON(VMX_EPT_WRITABLE_MASK != PT_WRITABLE_MASK);

/*
* If an SPTE is present already, it must be a leaf and therefore
* a large one. Drop it, and flush the TLB if needed, before
* installing sp.
*/
if (is_shadow_present_pte(*sptep))
drop_large_spte(kvm, sptep, flush);
if (is_shadow_present_pte(*sptep)) {
struct kvm_mmu_page *parent_sp;
LIST_HEAD(invalid_list);

parent_sp = sptep_to_sp(sptep);
WARN_ON_ONCE(parent_sp->role.level == PG_LEVEL_4K);

mmu_page_zap_pte(kvm, parent_sp, sptep, &invalid_list);
kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, true);
}

spte = make_nonleaf_spte(sp->spt, sp_ad_disabled(sp));

Expand Down
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