From: Sean Christopherson <seanjc@google.com>
To: Like Xu <like.xu.linux@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/3] KVM: x86/svm/pmu: Add AMD PerfMonV2 support
Date: Wed, 9 Nov 2022 14:51:55 +0000 [thread overview]
Message-ID: <Y2u+i1Qd9HkuwlGr@google.com> (raw)
In-Reply-To: <107f4040-e4cd-82df-01bc-f0d6a22be053@gmail.com>
On Wed, Nov 09, 2022, Like Xu wrote:
> On 28/10/2022 6:47 am, Sean Christopherson wrote:
> > What happens if userspace sets X86_FEATURE_PERFCTR_CORE when its not supported?
> > E.g. will KVM be coerced into taking a #GP on a non-existent counter?
>
> I'm getting a bit tired of this generic issue, what does KVM need to do when
> the KVM user space sets a capability that KVM doesn't support (like cpuid).
> Should it change the guest cpuid audibly or silently ? Should it report an
> error when the guest uses this unsupported capability at run time, or should
> it just let the KVM report an error when user space setting the cpuid ?
KVM should do nothing unless the bogus CPUID can be used to trigger unexpected
and/or unwanted behavior in the kernel, which is why I asked if KVM might end up
taking a #GP.
next prev parent reply other threads:[~2022-11-09 14:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-19 9:34 [PATCH v2 0/3] KVM: x86: Add AMD Guest PerfMonV2 PMU support Like Xu
2022-09-19 9:34 ` [PATCH v2 1/3] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic Like Xu
2022-09-22 0:20 ` Jim Mattson
2022-09-22 5:47 ` Like Xu
2022-09-22 6:20 ` Like Xu
2022-10-27 22:14 ` Sean Christopherson
2022-10-07 22:19 ` Sean Christopherson
2022-10-27 22:10 ` Sean Christopherson
2022-09-19 9:34 ` [PATCH v2 2/3] KVM: x86/svm/pmu: Add AMD PerfMonV2 support Like Xu
2022-09-21 0:06 ` Jim Mattson
2022-10-27 22:47 ` Sean Christopherson
2022-11-09 9:54 ` Like Xu
2022-11-09 14:51 ` Sean Christopherson [this message]
2022-09-19 9:34 ` [PATCH v2 3/3] KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022 Like Xu
2022-09-21 0:02 ` Jim Mattson
2022-10-27 22:37 ` Sean Christopherson
2022-11-10 9:26 ` Like Xu
2022-11-10 17:34 ` Sean Christopherson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=Y2u+i1Qd9HkuwlGr@google.com \
--to=seanjc@google.com \
--cc=kvm@vger.kernel.org \
--cc=like.xu.linux@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=pbonzini@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.