From: Sean Christopherson <seanjc@google.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
x86@kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Brijesh Singh <brijesh.singh@amd.com>
Subject: Re: [PATCH v2] KVM: SVM: Make sure GHCB is mapped before updating
Date: Thu, 8 Apr 2021 17:37:28 +0000 [thread overview]
Message-ID: <YG8/WHFOPX6H1eJf@google.com> (raw)
In-Reply-To: <923548be-db20-7eea-33aa-571347a95526@amd.com>
On Thu, Apr 08, 2021, Tom Lendacky wrote:
> On 4/8/21 12:10 PM, Sean Christopherson wrote:
> > On Thu, Apr 08, 2021, Tom Lendacky wrote:
> >> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> >> index 83e00e524513..7ac67615c070 100644
> >> --- a/arch/x86/kvm/svm/sev.c
> >> +++ b/arch/x86/kvm/svm/sev.c
> >> @@ -2105,5 +2105,8 @@ void sev_vcpu_deliver_sipi_vector(struct kvm_vcpu *vcpu, u8 vector)
> >> * the guest will set the CS and RIP. Set SW_EXIT_INFO_2 to a
> >> * non-zero value.
> >> */
> >> + if (WARN_ON_ONCE(!svm->ghcb))
> >
> > Isn't this guest triggerable? I.e. send a SIPI without doing the reset hold?
> > If so, this should not WARN.
>
> Yes, it is a guest triggerable event. But a guest shouldn't be doing that,
> so I thought adding the WARN_ON_ONCE() just to detect it wasn't bad.
> Definitely wouldn't want a WARN_ON().
WARNs are intended only for host issues, e.g. a malicious guest shouldn't be
able to crash the host when running with panic_on_warn.
next prev parent reply other threads:[~2021-04-08 17:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 16:54 [PATCH v2] KVM: SVM: Make sure GHCB is mapped before updating Tom Lendacky
2021-04-08 17:10 ` Sean Christopherson
2021-04-08 17:29 ` Tom Lendacky
2021-04-08 17:37 ` Sean Christopherson [this message]
2021-04-08 17:47 ` Tom Lendacky
2021-04-08 19:48 ` Sean Christopherson
2021-04-09 14:56 ` Tom Lendacky
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