kvm.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jim Mattson <jmattson@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	kvm list <kvm@vger.kernel.org>,
	Eric Hankland <ehankland@google.com>,
	Peter Shier <pshier@google.com>,
	Krish Sadhukhan <krish.sadhukhan@oracle.com>
Subject: Re: [PATCH] kvm: x86: Add Intel PMU MSRs to msrs_to_save[]
Date: Fri, 27 Sep 2019 10:36:14 -0700	[thread overview]
Message-ID: <CALMp9eSDrXLU2jHXAUYoDqVWnV5gPbT5DUmrhKVbtc6vW+sogA@mail.gmail.com> (raw)
In-Reply-To: <19db28c0-375a-7bc0-7151-db566ae85de6@redhat.com>

On Fri, Sep 27, 2019 at 8:19 AM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 27/09/19 16:40, Vitaly Kuznetsov wrote:
> > Paolo Bonzini <pbonzini@redhat.com> writes:
> >
> >> On 27/09/19 15:53, Vitaly Kuznetsov wrote:
> >>> Paolo Bonzini <pbonzini@redhat.com> writes:
> >>>
> >>>> Queued, thanks.
> >>>
> >>> I'm sorry for late feedback but this commit seems to be causing
> >>> selftests failures for me, e.g.:
> >>>
> >>> # ./x86_64/state_test
> >>> Testing guest mode: PA-bits:ANY, VA-bits:48,  4K pages
> >>> Guest physical address width detected: 46
> >>> ==== Test Assertion Failure ====
> >>>   lib/x86_64/processor.c:1089: r == nmsrs
> >>>   pid=14431 tid=14431 - Argument list too long
> >>>      1      0x000000000040a55f: vcpu_save_state at processor.c:1088 (discriminator 3)
> >>>      2      0x00000000004010e3: main at state_test.c:171 (discriminator 4)
> >>>      3      0x00007f881eb453d4: ?? ??:0
> >>>      4      0x0000000000401287: _start at ??:?
> >>>   Unexpected result from KVM_GET_MSRS, r: 36 (failed at 194)
> >>>
> >>> Is this something known already or should I investigate?
> >>
> >> No, I didn't know about it, it works here.
> >>
> >
> > Ok, this is a bit weird :-) '194' is 'MSR_ARCH_PERFMON_EVENTSEL0 +
> > 14'. In intel_pmu_refresh() nr_arch_gp_counters is set to '8', however,
> > rdmsr_safe() for this MSR passes in kvm_init_msr_list() (but it fails
> > for 0x18e..0x193!) so it stay in the list. get_gp_pmc(), however, checks
> > it against nr_arch_gp_counters and returns a failure.
>
> Huh, 194h apparently is a "FLEX_RATIO" MSR.  I agree that PMU MSRs need
> to be checked against CPUID before allowing them.

According to the SDM, volume 4, table 2-2, IA-32 Architectural MSRs,
194H is reserved. Sounds like your CPU is mis-architected. :-)

> Paolo
>
> > Oh, btw, this is Intel(R) Xeon(R) CPU E5-2603 v3
> >
> > So apparently rdmsr_safe() check in kvm_init_msr_list() is not enough,
> > for PMU MSRs we need to do extra.
>
>
>

  parent reply	other threads:[~2019-09-27 17:36 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-21 18:20 [PATCH] kvm: x86: Add Intel PMU MSRs to msrs_to_save[] Jim Mattson
2019-09-06 16:48 ` Jim Mattson
     [not found]   ` <8907173e-9f27-6769-09fc-0b82c22d6352@oracle.com>
2019-09-06 20:30     ` Jim Mattson
2019-09-06 20:43       ` Krish Sadhukhan
2019-09-06 21:08         ` Jim Mattson
2019-09-16 20:43           ` Jim Mattson
2019-09-17 12:39             ` Paolo Bonzini
2019-09-27 13:53               ` Vitaly Kuznetsov
2019-09-27 14:00                 ` Paolo Bonzini
2019-09-27 14:40                   ` Vitaly Kuznetsov
2019-09-27 15:19                     ` Paolo Bonzini
2019-09-27 15:26                       ` Sean Christopherson
2019-09-27 15:46                         ` Vitaly Kuznetsov
2019-09-27 15:55                           ` Jim Mattson
2019-09-27 15:59                             ` Jim Mattson
2019-09-27 16:01                             ` Paolo Bonzini
2019-09-27 15:58                           ` Xiaoyao Li
2019-09-27 16:06                             ` Paolo Bonzini
2019-09-27 16:10                               ` Jim Mattson
2019-09-27 16:32                                 ` Paolo Bonzini
2019-09-27 17:14                                   ` Sean Christopherson
2019-09-27 17:19                                     ` Paolo Bonzini
2019-09-27 17:23                                       ` Sean Christopherson
2019-09-27 17:30                                     ` Jim Mattson
2019-09-27 17:35                                       ` Sean Christopherson
2019-09-27 19:03                                         ` Jim Mattson
2019-09-27 17:22                                   ` Jim Mattson
2019-09-27 17:34                                     ` Sean Christopherson
2019-09-27 17:26                                   ` Jim Mattson
2019-09-27 16:06                             ` Jim Mattson
2019-09-27 17:36                       ` Jim Mattson [this message]
2019-09-27 17:45                         ` 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=CALMp9eSDrXLU2jHXAUYoDqVWnV5gPbT5DUmrhKVbtc6vW+sogA@mail.gmail.com \
    --to=jmattson@google.com \
    --cc=ehankland@google.com \
    --cc=krish.sadhukhan@oracle.com \
    --cc=kvm@vger.kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=pshier@google.com \
    --cc=vkuznets@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).