RE: [PATCH] i386: Disable BTS and PEBS

[Duan, Zhenzhong]

>-----Original Message-----
>From: Paolo Bonzini <paolo.bonzini@gmail.com> On Behalf Of Paolo Bonzini
>Sent: Wednesday, July 20, 2022 2:19 AM
>To: Christopherson,, Sean <seanjc@google.com>
>Cc: Duan, Zhenzhong <zhenzhong.duan@intel.com>; qemu-
>devel@nongnu.org; mtosatti@redhat.com; likexu@tencent.com; Ma,
>XiangfeiX <xiangfeix.ma@intel.com>
>Subject: Re: [PATCH] i386: Disable BTS and PEBS
>
>On 7/18/22 22:12, Sean Christopherson wrote:
>> On Mon, Jul 18, 2022, Paolo Bonzini wrote:
>>> This needs to be fixed in the kernel because old QEMU/new KVM is
>supported.
>>
>> I can't object to adding a quirk for this since KVM is breaking
>> userspace, but on the KVM side we really need to stop "sanitizing"
>> userspace inputs unless it puts the host at risk, because inevitably it leads
>to needing a quirk.
>
>The problem is not the sanitizing, it's that userspace literally cannot know
>that this needs to be done because the feature bits are "backwards"
>(1 = unavailable).
>
>The right way to fix it is probably to use feature MSRs and, by default, leave
>the features marked as unavailable.  I'll think it through and post a patch
>tomorrow for both KVM and QEMU (to enable PEBS).
Hi Paolo,

Can we ask the status of your patch? QA still reproduce with newest upstream 
code.

Thanks
Zhenzhong