From: Paolo Bonzini <pbonzini@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Maxim Levitsky <mlevitsk@redhat.com>
Subject: Re: [PATCH] KVM: selftests: Don't skip L2's VMCALL in SMM test for SVM guest
Date: Wed, 26 Jan 2022 16:45:56 +0100 [thread overview]
Message-ID: <e570f7d2-03fc-1498-bd91-6fd7aabae766@redhat.com> (raw)
In-Reply-To: <20220125221725.2101126-1-seanjc@google.com>
On 1/25/22 23:17, Sean Christopherson wrote:
> Don't skip the vmcall() in l2_guest_code() prior to re-entering L2, doing
> so will result in L2 running to completion, popping '0' off the stack for
> RET, jumping to address '0', and ultimately dying with a triple fault
> shutdown.
>
> It's not at all obvious why the test re-enters L2 and re-executes VMCALL,
> but presumably it serves a purpose. The VMX path doesn't skip vmcall(),
> and the test can't possibly have passed on SVM, so just do what VMX does.
>
> Fixes: d951b2210c1a ("KVM: selftests: smm_test: Test SMM enter from L2")
> Cc: Maxim Levitsky <mlevitsk@redhat.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> tools/testing/selftests/kvm/x86_64/smm_test.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
> index 2da8eb8e2d96..a626d40fdb48 100644
> --- a/tools/testing/selftests/kvm/x86_64/smm_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
> @@ -105,7 +105,6 @@ static void guest_code(void *arg)
>
> if (cpu_has_svm()) {
> run_guest(svm->vmcb, svm->vmcb_gpa);
> - svm->vmcb->save.rip += 3;
> run_guest(svm->vmcb, svm->vmcb_gpa);
> } else {
> vmlaunch();
>
> base-commit: e2e83a73d7ce66f62c7830a85619542ef59c90e4
Queued, thanks.
Paolo
prev parent reply other threads:[~2022-01-26 15:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-25 22:17 [PATCH] KVM: selftests: Don't skip L2's VMCALL in SMM test for SVM guest Sean Christopherson
2022-01-26 15:23 ` Vitaly Kuznetsov
2022-01-26 15:45 ` Paolo Bonzini [this message]
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