Message-ID: <e5bf7da5-df29-31c6-6d33-81bbecb849ba@redhat.com>
Date:   Mon, 6 Mar 2023 22:25:29 +0100
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Subject: Re: [PATCH 0/2] KVM: x86: Propagate AMD-specific IBRS bits to guests
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To:     Sean Christopherson <seanjc@google.com>,
        Borislav Petkov <bp@alien8.de>
Cc:     Takahiro Itazuri <itazur@amazon.com>, dave.hansen@linux.intel.com,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        mingo@redhat.com, tglx@linutronix.de, x86@kernel.org,
        zulinx86@gmail.com
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 <20230228222416.61484-1-itazur@amazon.com> <Y/6FIeJ5KCOfKEPN@zn.tnic>
 <ZAZYKe4L8jhMG4An@google.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
In-Reply-To: <ZAZYKe4L8jhMG4An@google.com>
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On 3/6/23 22:16, Sean Christopherson wrote:
>> Not harmless - cpufeatures.h should contain flags which the kernel uses
>> and not*every*  CPUID bit out there.
>
> I thought that the consensus was that adding unused-by-the-kernel flags to
> cpufeatures.h is ok so long as the feature is hidden from /proc/cpuinfo and the
> kernel already dedicates a word to the CPUID leaf?
Yeah, I understand adding no new CPUID leaf just for KVM, but you don't 
gain anything really from not having X86_FEATURE_* defines.

Paolo