Re: [Qemu-devel] [PATCH 2/2] target-i386: automatically raise cpuid level to 0xd

[Eduardo Habkost]

On Thu, Jun 18, 2015 at 01:12:32PM -0400, Bandan Das wrote:
> Eduardo Habkost <address@hidden> writes:
> 
> > On Thu, Jun 18, 2015 at 05:24:24PM +0200, Radim Krčmář wrote:
> >> We already bump to level 7 if features there are requested, so do the
> >> same for 0xD.
> 
> But doesn't bumping to 7 for feat[ebx] have the potential to break
> ABI too ?

It's not the auto-bumping that breaks ABI, but having older
machine-types now exposing different CPUID data to guests after applying
the patch.

The auto-bump to 7 was introduced at the same time we introduced the
first CPUID[7] features, so you couldn't have any running machines that
would break.

-- 
Eduardo