| From | Greg Kroah-Hartman <> | Subject | [PATCH 5.14 052/172] KVM: x86: Clear KVMs cached guest CR3 at RESET/INIT | Date | Mon, 4 Oct 2021 14:51:42 +0200 |
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From: Sean Christopherson <seanjc@google.com>
commit 03a6e84069d1870f5b3d360e64cb330b66f76dee upstream.
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@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210921000303.400537-3-seanjc@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/x86/kvm/x86.c | 3 +++ 1 file changed, 3 insertions(+)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -10873,6 +10873,9 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcp static_call(kvm_x86_vcpu_reset)(vcpu, init_event); + vcpu->arch.cr3 = 0; + kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3); + /* * Reset the MMU context if paging was enabled prior to INIT (which is * implied if CR0.PG=1 as CR0 will be '0' prior to RESET). Unlike the
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