linux-kernel - Re: [PATCH 2/2] KVM: x86/pmu: do not mask the value that is written to fixed PMUs

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Message-ID: <c0db3010-96a7-c58e-ee08-a5703e40b3f4@redhat.com>
Date:   Wed, 22 May 2019 12:27:08 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Sean Christopherson <sean.j.christopherson@...el.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Subject: Re: [PATCH 2/2] KVM: x86/pmu: do not mask the value that is written
 to fixed PMUs

On 20/05/19 21:01, Sean Christopherson wrote:
> Would it make sense to inject a #GP if the guest attempts to set bits that
> are reserved to be zero, e.g. based on guest CPUID?

Yes, though it was not clear from the SDM quote that hardware enforces
that (I guess the hint is that they "must" be written as zero rather
than "should").

I'll include this patch in my next pull request with fixed commit
message, and do the #GP change separately.

Paolo