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From: Jim Mattson <jmattson@google.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Jue Wang <juew@google.com>
Subject: Re: [PATCH 1/3] KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS)
Date: Thu, 12 May 2022 15:43:38 -0700	[thread overview]
Message-ID: <CALMp9eSzx6SEa+rrBR2DpizuwqUzYvU7GNQrW=AOToeTp9mC8Q@mail.gmail.com> (raw)
In-Reply-To: <20220512222716.4112548-2-seanjc@google.com>

On Thu, May 12, 2022 at 3:27 PM Sean Christopherson <seanjc@google.com> wrote:
>
> Return '1', not '-1', when handling an illegal WRMSR to a MCi_CTL or
> MCi_STATUS MSR.  The behavior of "all zeros' or "all ones" for CTL MSRs
> is architectural, as is the "only zeros" behavior for STATUS MSRs.  I.e.
> the intent is to inject a #GP, not exit to userspace due to an unhandled
> emulation case.  Returning '-1' gets interpreted as -EPERM up the stack
> and effecitvely kills the guest.
>
> Fixes: 890ca9aefa78 ("KVM: Add MCE support")
> Fixes: 9ffd986c6e4e ("KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0")
> Cc: stable@vger.kernel.org
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
Reviewed-by: Jim Mattson <jmattson@google.com>

  reply	other threads:[~2022-05-12 22:43 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-12 22:27 [PATCH 0/3] KVM: x86: WRMSR MCi_CTL/STATUS bug fix and cleanups Sean Christopherson
2022-05-12 22:27 ` [PATCH 1/3] KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS) Sean Christopherson
2022-05-12 22:43   ` Jim Mattson [this message]
2022-05-12 22:27 ` [PATCH 2/3] KVM: x86: Use explicit case-statements for MCx banks in {g,s}et_msr_mce() Sean Christopherson
2022-05-12 23:23   ` Jim Mattson
2022-05-12 22:27 ` [PATCH 3/3] KVM: x86: Add helpers to identify CTL and STATUS MCi MSRs Sean Christopherson
2022-05-12 23:32   ` Jim Mattson

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