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Re: [Qemu-devel] Pentium Pro Feature Bugs
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] Pentium Pro Feature Bugs |
Date: |
Fri, 17 May 2019 17:40:31 -0300 |
User-agent: |
Mutt/1.10.1 (2018-07-13) |
On Fri, May 17, 2019 at 04:06:20PM -0400, tedheadster wrote:
> On Fri, May 17, 2019 at 2:15 PM Eduardo Habkost <address@hidden> 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