Re: [PATCH] KVM: nVMX: Advertise IA32_PAT in VM exit control

[Gleb Natapov <gleb@redhat.com>]

On Mon, Aug 05, 2013 at 01:04:25PM +0200, Jan Kiszka wrote:
> On 2013-08-05 13:00, Arthur Chunqi Li wrote:
> > On Mon, Aug 5, 2013 at 6:55 PM, Gleb Natapov <gleb@redhat.com> wrote:
> >> On Mon, Aug 05, 2013 at 12:38:32PM +0200, Jan Kiszka wrote:
> >>> On 2013-08-05 11:36, Gmail wrote:
> >>>>
> >>>>
> >>>>> On Mon, Aug 05, 2013 at 05:10:35PM +0800, Arthur Chunqi Li wrote:
> >>>>>> Advertise VM_EXIT_SAVE_IA32_PAT and VM_EXIT_LOAD_IA32_PAT.
> >>>>>>
> >>>>>> Signed-off-by: Arthur Chunqi Li <yzt356@gmail.com>
> >>>>>> ---
> >>>>>> arch/x86/kvm/vmx.c |    3 ++-
> >>>>>> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>>>>>
> >>>>>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> >>>>>> index 45fd70c..240f0db 100644
> >>>>>> --- a/arch/x86/kvm/vmx.c
> >>>>>> +++ b/arch/x86/kvm/vmx.c
> >>>>>> @@ -2198,7 +2198,8 @@ static __init void nested_vmx_setup_ctls_msrs(void)
> >>>>>> #else
> >>>>>>    nested_vmx_exit_ctls_high = 0;
> >>>>>> #endif
> >>>>>> -    nested_vmx_exit_ctls_high |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR;
> >>>>>> +    nested_vmx_exit_ctls_high |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
> >>>>>> +        VM_EXIT_LOAD_IA32_PAT | VM_EXIT_SAVE_IA32_PAT;
> >>>>>>
> >>>>> You should not set those if host does not support them, otherwise
> >>>>> GUEST_IA32_PAT may not be available
> >>>> To Jan,
> >>>> Is this different from IA32_EFER?
> >>>
> >>> As we use a real VMCS to keep GUEST/HOST_IA32_EFER, we actually do
> >>> depend on the existence of the host feature. So my patch requires an
> >>> update as you noted.
> >>>
> >> Your patch didn't add new users of GUEST_IA32_PAT and
> >> VM_ENTRY_LOAD_IA32_PAT is enabled by nested only if host has it, so I am
> >> not sure why you are saying that patch should be updated.
> > I think Jan points [1] and you refer to another.
> > 
> > [1] http://www.mail-archive.com/kvm@vger.kernel.org/msg94188.html
> 
> Yep, that's what I was referring to.
> 
Ah, too many patches :)

--
			Gleb.