linux-kernel - Re: [PATCH v5 1/3] KVM: x86: Provide per VM capability for disabling PMU virtualization

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Message-ID: <09d8b472-000b-7150-f60d-ffb5706b164e@gmail.com>
Date:   Wed, 9 Feb 2022 18:33:00 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     "Paolo Bonzini - Distinguished Engineer (kernel-recipes.org) (KVM HoF)" 
        <pbonzini@...hat.com>
Cc:     kvm@...r.kernel.org, seanjc@...gle.com,
        David Dunn <daviddunn@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Joerg Roedel <joro@...tes.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 1/3] KVM: x86: Provide per VM capability for disabling
 PMU virtualization

cc LKML and full list of KVM reviewers.

On 25/1/2022 2:39 am, Jim Mattson wrote:
> On Sun, Jan 23, 2022 at 10:45 AM David Dunn <daviddunn@...gle.com> wrote:
>>
>> KVM_CAP_PMU_DISABLE is used to disable PMU virtualization on individual
>> x86 VMs.  PMU configuration must be done prior to creating VCPUs.
>>
>> To enable future extension, KVM_CAP_PMU_CAPABILITY reports available
>> settings via bitmask when queried via check_extension.
>>
>> For VMs that have PMU virtualization disabled, usermode will need to
>> clear CPUID leaf 0xA to notify guests.
>>
>> Signed-off-by: David Dunn <daviddunn@...gle.com>
> 
> Nit: The two references to CPUID leaf 0xA should be qualified as
> applying only to Intel VMs.
> 
> Reviewed-by: Jim Mattson <jmattson@...gle.com>
> 

Nit: It looks like we already have "#define KVM_CAP_SYS_ATTRIBUTES 209".

Hope it helps a little:

Reviewed-by: Like Xu <likexu@...cent.com>