[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <3c28c9bf-d14e-3f9b-0973-ba4a438aaa33@amd.com>
Date: Thu, 8 Apr 2021 12:47:53 -0500
From: Tom Lendacky <thomas.lendacky@....com>
To: Sean Christopherson <seanjc@...gle.com>
Cc: kvm@...r.kernel.org, linux-kernel@...r.kernel.org, x86@...nel.org,
Paolo Bonzini <pbonzini@...hat.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Borislav Petkov <bp@...en8.de>, Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH v2] KVM: SVM: Make sure GHCB is mapped before updating
On 4/8/21 12:37 PM, Sean Christopherson wrote:
> 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.
>
Ah, yeah, forgot about panic_on_warn. I can go back to the original patch
or do a pr_warn_once(), any pref?
Thanks,
Tom
Powered by blists - more mailing lists