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

[Jan Kiszka <jan.kiszka@web.de>]

[-- Attachment #1: Type: text/plain, Size: 1824 bytes --]

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.

Jan



[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 263 bytes --]