lkml.org 
[lkml]   [2020]   [Mar]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 2/6] KVM: x86: Fix CPUID range check for Centaur and Hypervisor ranges
On Mon, Mar 2, 2020 at 11:57 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:

> The bad behavior can be visually confirmed by dumping CPUID output in
> the guest when running Qemu with a stable TSC, as Qemu extends the limit
> of range 0x40000000 to 0x40000010 to advertise VMware's cpuid_freq,
> without defining zeroed entries for 0x40000002 - 0x4000000f.

I think it could be reasonably argued that this is a userspace bug.
Clearly, when userspace explicitly supplies the results for a leaf,
those results override the default CPUID values for that leaf. But I
haven't seen it documented anywhere that leaves *not* explicitly
supplied by userspace will override the default CPUID values, just
because they happen to appear in some magic range.

\
 
 \ /
  Last update: 2020-03-03 04:26    [W:0.180 / U:5.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site