Explicitly zero the guest's CR3 and mark it available+dirty at RESET/INIT. Per Intel's SDM and AMD's APM, CR3 is zeroed at both RESET and INIT. For RESET, this is a nop as vcpu is zero-allocated. For INIT, the bug has likely escaped notice because no firmware/kernel puts its page tables root at PA=0, let alone relies on INIT to get the desired CR3 for such page tables. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e77a5bf2d940..2cb38c67ed43 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10899,6 +10899,9 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) kvm_set_rflags(vcpu, X86_EFLAGS_FIXED); kvm_rip_write(vcpu, 0xfff0); + vcpu->arch.cr3 = 0; + kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3); + /* * CR0.CD/NW are set on RESET, preserved on INIT. Note, some versions * of Intel's SDM list CD/NW as being set on INIT, but they contradict -- 2.33.0.464.g1972c5931b-goog
