From: Eduardo Habkost <ehabkost@redhat.com>
To: whiteheadm@acm.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Thomas Huth <thuth@redhat.com>,
qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] Pentium Pro Feature Bugs
Date: Fri, 17 May 2019 17:40:31 -0300 [thread overview]
Message-ID: <20190517204031.GN28853@habkost.net> (raw)
In-Reply-To: <CAP8WD_aUC9V1wPuC2w5jzAPrThrODfxjA3h3p8z8WAyKaG8Tuw@mail.gmail.com>
On Fri, May 17, 2019 at 04:06:20PM -0400, tedheadster wrote:
> On Fri, May 17, 2019 at 2:15 PM Eduardo Habkost <ehabkost@redhat.com> wrote:
> > Are you running the same kernel version on all VMs?
> > X86_FEATURE_CPUID was added in Linux v4.11.
> >
>
> Eduardo,
> I am running a 4.9.162 virtual machine (very intentionally, the
> drivers I need got broken in 4.11) inside of a 5.1.2 host.
That would explain why you don't see cpuid on /proc/cpuinfo.
v4.9.162 doesn't have the flag.
>
> X86_FEATURE_CPUID is certainly defined in
> arch/x86/kernel/cpu/capflags.c but nothing much seems to be done with
> it.
I don't see X86_FEATURE_CPUID in v4.9.162, which kernel source
version are you looking at?
>
> The whole reason this came up is I was running 'perf top' on the
> virtual host and it was spending the most kernel time calling cpuid(),
> which seemed wrong.
Which process was doing it?
--
Eduardo
prev parent reply other threads:[~2019-05-17 20:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-01 3:36 [Qemu-devel] Pentium Pro Feature Bugs tedheadster
2019-04-01 5:35 ` Thomas Huth
2019-04-01 7:28 ` Paolo Bonzini
2019-05-17 0:30 ` tedheadster
2019-05-17 2:57 ` Paolo Bonzini
2019-05-17 3:01 ` tedheadster
2019-05-17 18:15 ` Eduardo Habkost
2019-05-17 20:06 ` tedheadster
2019-05-17 20:40 ` Eduardo Habkost [this message]
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