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SubjectRe: [PATCH MANUALSEL 5.14 5/9] KVM: x86: VMX: synthesize invalid VM exit when emulating invalid guest state
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On 06/10/21 15:30, Sasha Levin wrote:
> From: Maxim Levitsky <mlevitsk@redhat.com>
>
> [ Upstream commit c42dec148b3e1a88835e275b675e5155f99abd43 ]
>
> Since no actual VM entry happened, the VM exit information is stale.
> To avoid this, synthesize an invalid VM guest state VM exit.
>
> Suggested-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
> Message-Id: <20210913140954.165665-6-mlevitsk@redhat.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
> arch/x86/kvm/vmx/vmx.c | 17 ++++++++++++++---
> 1 file changed, 14 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 256f8cab4b8b..339116ff236f 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6607,10 +6607,21 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu)
> vmx->loaded_vmcs->soft_vnmi_blocked))
> vmx->loaded_vmcs->entry_time = ktime_get();
>
> - /* Don't enter VMX if guest state is invalid, let the exit handler
> - start emulation until we arrive back to a valid state */
> - if (vmx->emulation_required)
> + /*
> + * Don't enter VMX if guest state is invalid, let the exit handler
> + * start emulation until we arrive back to a valid state. Synthesize a
> + * consistency check VM-Exit due to invalid guest state and bail.
> + */
> + if (unlikely(vmx->emulation_required)) {
> + vmx->fail = 0;
> + vmx->exit_reason.full = EXIT_REASON_INVALID_STATE;
> + vmx->exit_reason.failed_vmentry = 1;
> + kvm_register_mark_available(vcpu, VCPU_EXREG_EXIT_INFO_1);
> + vmx->exit_qualification = ENTRY_FAIL_DEFAULT;
> + kvm_register_mark_available(vcpu, VCPU_EXREG_EXIT_INFO_2);
> + vmx->exit_intr_info = 0;
> return EXIT_FASTPATH_NONE;
> + }
>
> trace_kvm_entry(vcpu);
>
>

NACK

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