From: "Radim Krčmář" <rkrcmar@redhat.com>
To: kmeaw@yandex-team.ru
Cc: "Gabriel L. Somlo" <gsomlo@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"gleb@kernel.org" <gleb@kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>
Subject: Re: [PATCH] KVM: Handle MSR_IA32_PERF_CTL
Date: Fri, 27 May 2016 17:22:25 +0200 [thread overview]
Message-ID: <20160527152224.GA11721@potion> (raw)
In-Reply-To: <920591464331762@webcorp02f.yandex-team.ru>
2016-05-27 09:49+0300, kmeaw@yandex-team.ru:
> 26.05.2016, 23:44, "Gabriel L. Somlo" <gsomlo@gmail.com>:
>> On Thu, May 26, 2016 at 10:39:31PM +0200, Radim Krčmář wrote:
>>> 2016-05-26 10:32+0300, kmeaw@yandex-team.ru:
>>> > This patch implements a dummy handler for MSR_IA32_PERF_CTL to avoid the
>>> > crashes. Most notably it fixes an issue with MacOS X 10.10 kernel.
>>> Does MacOS X write it too?
>>
>> After setting /sys/module/kvm/parameters/ignore_msrs, all I get in
>> dmesg after firing up OS X is:
>>
>> vcpu0 ignored rdmsr: 0x199
>>
>> So no, I don't think it would try to write it.
>
> That's right, OS X does not issue an wrmsr to 0x199. More specifically, I have not
> observed that on my KVM instances. Should I remove the "wrmsr" portion from the
> patch?
Yes, please. Silently ignoring the write is worse than #GP and #GP is
not a problem, so I wouldn't bother with a phony implementation.
Returning 0 on read is ok as seems to mean P-state=0, which is within
expectations.
(I wonder why MacOS X doesn't read IA32_PERF_STATUS, though.)
next prev parent reply other threads:[~2016-05-27 15:22 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-26 7:32 [PATCH] KVM: Handle MSR_IA32_PERF_CTL kmeaw
2016-05-26 20:39 ` Radim Krčmář
2016-05-26 20:44 ` Gabriel L. Somlo
[not found] ` <920591464331762@webcorp02f.yandex-team.ru>
2016-05-27 15:22 ` Radim Krčmář [this message]
2016-05-27 15:38 ` Radim Krčmář
2016-05-31 7:53 ` Paolo Bonzini
2016-05-31 13:05 ` Radim Krčmář
[not found] ` <1317601464689200@webcorp01d.yandex-team.ru>
2016-05-31 13:16 ` [PATCH v3] " Radim Krčmář
2016-05-31 14:38 ` [PATCH] " Dmitry Bilunov
2016-05-31 14:57 ` Radim Krčmář
2016-05-27 15:28 ` Radim Krčmář
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=20160527152224.GA11721@potion \
--to=rkrcmar@redhat.com \
--cc=gleb@kernel.org \
--cc=gsomlo@gmail.com \
--cc=kmeaw@yandex-team.ru \
--cc=kvm@vger.kernel.org \
--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.