Re: [Qemu-devel] [RFC PATCH] i386: Remove ospke CPUID flag name

[Eduardo Habkost <ehabkost@redhat.com>]

On Tue, Jun 12, 2018 at 05:12:58PM +0200, Paolo Bonzini wrote:
> On 12/06/2018 17:01, Eduardo Habkost wrote:
> >>>
> >>> Remove OSPKE from the feature name array so users don't try to
> >>> configure it manually.
> >>>
> >>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> >> Yes, it's the same as OSXSAVE.  Thanks!
> > CR4_OSXSAVE_MASK is automatically enabled on user-mode QEMU,
> > though.
> > 
> > My question is if it would make any sense to enable CR4_PKE_MASK
> > too.
> 
> If you mean OSPKE, then yes---if PKU is available.  Likewise, OSXSAVE
> should only be enabled if XSAVE is available.

Yeah, I mean enabling it only if PKU is available, like we
already do with OSXAVE/XSAVE.

But we don't do it today, so enabling it automatically in
CONFIG_USER_ONLY would be a new feature.  Would it be useful for
anything, though?

I'm asking that to find out if somebody could be already using
"-cpu ...,+ospke" with user-mode QEMU today (which this patch
would break).  If RDPKRU/WRPKRU is useless under user-mode QEMU,
than we don't need to worry about that.

-- 
Eduardo