diff options
| author |   Sean Christopherson <seanjc@google.com> | 2020-12-17 16:31:36 -0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2021-01-07 18:00:23 -0500 |
| commit | 2aa078932ff6c66bf10cc5b3144440dbfa7d813d (patch) | |
| tree | 9e6c32d44dbdaf5162ef1dca29da1c2e227574ed /arch/x86/kvm/mmu/tdp_mmu.c | |
| parent | Linux 5.10 (diff) | |
| download | linux-dev-2aa078932ff6c66bf10cc5b3144440dbfa7d813d.tar.xz linux-dev-2aa078932ff6c66bf10cc5b3144440dbfa7d813d.zip | |
KVM: x86/mmu: Use -1 to flag an undefined spte in get_mmio_spte()
Return -1 from the get_walk() helpers if the shadow walk doesn't fill at
least one spte, which can theoretically happen if the walk hits a
not-present PDPTR. Returning the root level in such a case will cause
get_mmio_spte() to return garbage (uninitialized stack data). In
practice, such a scenario should be impossible as KVM shouldn't get a
reserved-bit page fault with a not-present PDPTR.
Note, using mmu->root_level in get_walk() is wrong for other reasons,
too, but that's now a moot point.
Fixes: 95fb5b0258b7 ("kvm: x86/mmu: Support MMIO in the TDP MMU")
Cc: Ben Gardon <bgardon@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20201218003139.2167891-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 84c8f06bec26..50cec7a15ddb 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1152,8 +1152,8 @@ int kvm_tdp_mmu_get_walk(struct kvm_vcpu *vcpu, u64 addr, u64 *sptes) { struct tdp_iter iter; struct kvm_mmu *mmu = vcpu->arch.mmu; - int leaf = vcpu->arch.mmu->shadow_root_level; gfn_t gfn = addr >> PAGE_SHIFT; + int leaf = -1; tdp_mmu_for_each_pte(iter, mmu, gfn, gfn + 1) { leaf = iter.level; |