Re: [Xen-devel] [PATCH V4 6/6] x86/hvm: pkeys, add pkeys support for cpuid handling

["Han, Huaitong" <huaitong.han@xxxxxxxxx>]

On Tue, 2015-12-22 at 01:30 -0700, Jan Beulich wrote:
> > > > On 22.12.15 at 03:54, <huaitong.han@xxxxxxxxx> wrote:
> > On Mon, 2015-12-21 at 08:07 -0700, Jan Beulich wrote:
> > > > > > On 21.12.15 at 08:21, <huaitong.han@xxxxxxxxx> wrote:
> > > > @@ -4600,6 +4600,14 @@ void hvm_cpuid(unsigned int input,
> > > > unsigned
> > > > int *eax, unsigned int *ebx,
> > > >          /* Don't expose INVPCID to non-hap hvm. */
> > > >          if ( (count == 0) && !hap_enabled(d) )
> > > >              *ebx &= ~cpufeat_mask(X86_FEATURE_INVPCID);
> > > > +
> > > > +        /* X86_FEATURE_PKU is not yet implemented for shadow
> > > > paging. */
> > > > +        if ( (count == 0) && !hap_enabled(d) )
> > > > +            *ecx &= ~cpufeat_mask(X86_FEATURE_PKU);
> > > 
> > > I'm still missing the xsave dependency here.
> > Xsave dependency deletion becasue we use RDPKRU to get PKRU
> > register
> > value instead of XSAVE now.
> 
> What the hypervisor does doesn't matter here. The question is
> whether from an architectural standpoint XSAVE is a prerequsite.
> If it is, then you need to clear PKU when _guest_ XSAVE is clear.
No, XSAVE is not a prerequsite.
> 
> Jan
> 
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel