Re: [PATCH v2 2/5] VMX/Viridian: suppress MSR-based APIC suggestion when having APIC-V

[George Dunlap <george.dunlap@eu.citrix.com>]

On 06/25/2013 11:29 AM, Paul Durrant wrote:
>> -----Original Message-----
>> From: Jan Beulich [mailto:JBeulich@suse.com]
>> Sent: 24 June 2013 08:05
>> To: xen-devel
>> Cc: Paul Durrant; George Dunlap; Eddie Dong; Jun Nakajima; Yang Z Zhang;
>> Keir (Xen.org)
>> Subject: [PATCH v2 2/5] VMX/Viridian: suppress MSR-based APIC suggestion
>> when having APIC-V
>>
>> When the CPU has the necessary capabilities, having Windows use
>> synthetic MSR reads/writes is bogus, as this still requires emulation
>> (which is pretty much guaranteed to be slower than having the hardware
>> carry out the operation).
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>>
>
> Seems better just to not use the MSR in this case so I favour this patch over #1, hence
>
> Ack-ed by: Paul Durrant <paul.durrant@citrix.com>

This may push this over into the "#2 is probably a better idea" 
category; Paul, Yang, and Jan all think it's less intrusive.

Jan, I think it's your call -- You have an ack from me to put either #1 
or #2 in for 4.3 (but please not both).

  -George