Messages in this thread Patch in this message | | | Date | Wed, 21 Apr 2021 19:21:21 -0700 | Subject | [PATCH v2 2/9] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode | From | Sean Christopherson <> |
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Check CR3 for an invalid GPA even if the vCPU isn't in long mode. For bigger emulation flows, notably RSM, the vCPU mode may not be accurate if CR0/CR4 are loaded after CR3. For MOV CR3 and similar flows, the caller is responsible for truncating the value.
Note, SMRAM.CR3 is read-only, so this is mostly a theoretical bug since KVM will not have stored an illegal CR3 into SMRAM during SMI emulation.
Fixes: 660a5d517aaa ("KVM: x86: save/load state on SMM switch") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/x86.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index c9ba6f2d9bcd..63af93211871 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1078,10 +1078,15 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3) return 0; } - if (is_long_mode(vcpu) && kvm_vcpu_is_illegal_gpa(vcpu, cr3)) + /* + * Do not condition the GPA check on long mode, this helper is used to + * stuff CR3, e.g. for RSM emulation, and there is no guarantee that + * the current vCPU mode is accurate. + */ + if (kvm_vcpu_is_illegal_gpa(vcpu, cr3)) return 1; - else if (is_pae_paging(vcpu) && - !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) + + if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)) return 1; kvm_mmu_new_pgd(vcpu, cr3, skip_tlb_flush, skip_tlb_flush); -- 2.31.1.498.g6c1eba8ee3d-goog
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