Re: [PATCH RFC 0/3] VMX: fix interaction of Viridian emulation with advanced features

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

On 21/06/13 14:57, Jan Beulich wrote:
>>>> On 21.06.13 at 12:31, "Jan Beulich" <JBeulich@suse.com> wrote:
>> 1: VMX: fix interaction of APIC-V and Viridian emulation
>> 2: VMX/Viridian: suppress MSR-based APIC suggestion when having APIC-V
>> 3: Viridian: populate CPUID leaf 6
>>
>> The concepts patch 1 bases upon have been tested to fix the Win2008
>> boot hang previously reported, but the specific patch here so far hasn't
>> got validated. Additionally I will also want to know whether patch 2
>> alone would also suffice to address the problem (it should in theory, but
>> so far it was only tested when at the same time also not setting
>> CPUID3A_MSR_APIC_ACCESS) - if it does, that might be a candidate
>> to still go into 4.3.
> George,
>
> the tests meanwhile completed successfully, i.e. both patch 1
> and patch 2 alone address the issue. I'd therefore like to propose
> patch 2 as an immediate non-intrusive fix for 4.3, whereas I'd be
> fine deferring the first one until after 4.3; deferring the third one
> seems obvious as it is not fixing any known bug.
>
> Paul, would you btw feel like reviewing/acking patches 2 and 3?

Just to clarify -- #1 makes it so that the software EOI does what the 
hardware EOI would do if it were used instead?

It's a bit hard to tell which one of 1 or 2 is the lowest risk from a 
release perspective -- my instinct is to go with #1 (assuming I've 
understood it correctly), as it relies on expected behavior of the 
hardware, not on expected behavior of Windows.  But I think whichever 
you think is best is fine with me, as long as you get an Ack from Paul 
for #2.

  -George