Re: [Qemu-devel] Pentium Pro Feature Bugs

[Eduardo Habkost]

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