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Re: [Xen-devel] GPU passthrough performance regression in >4GB vms due to XSA-60 changes

On 05/19/2014 02:44 PM, Jan Beulich wrote:
On 19.05.14 at 14:17, <tomasz.wroblewski@xxxxxxxxx> wrote:
On 05/19/2014 02:06 PM, Jan Beulich wrote:
On 19.05.14 at 13:32, <tomasz.wroblewski@xxxxxxxxx> wrote:
Yeah I gave about a day of effort to port us onto unstable and test
there but it sadly looks to be a bigger job, so leaving that as a last
resort (though planning to spend couple more days on it soon).
Then as an alternative did you try pulling over the EPT changes
from -unstable?
That would be indeed preferable, I've looked over them but couldn't
figure out which particular change would fix the EPT update after MTRR
enable. Do you remember which that was? I could test it and try to
narrow any other commits it'd require (seems there were a lot of ept
related changes)
I used plural for a reason - I'm afraid you would need to start out with
taking them all, and then possibly determine which ones to drop as
being unrelated to the issue at hand.
Looks like a partial backport of your commit

commit aa9114edd97b292cd89b3616e3f2089471fd2201
Author: Jan Beulich <jbeulich@xxxxxxxx>
Date:   Thu Apr 10 16:01:41 2014 +0200

    x86/EPT: force re-evaluation of memory type as necessary

is all that's necessary. Attaching it versus 4.3.2. I only left the memory_type_change calls in MTRR related areas, since only this is problematic for the particular issue. This is probably good enough for us, thanks for the pointers! Do you think this one is a relatively safe for the stable branches?

Attachment: ept-bp-aa9114edd97b292cd89b3616e3f2089471fd2201
Description: Text document

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