Re: [Xen-devel] preparations for 4.4.1, 4.3.3, and 4.2.5

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.05.14 at 15:31, <boris.ostrovsky@xxxxxxxxxx> wrote:
> On 05/20/2014 08:28 AM, Jan Beulich wrote:
>>>>> On 19.05.14 at 22:14, <boris.ostrovsky@xxxxxxxxxx> wrote:
>>> Hypervisor:
>>> 88e64cb x86/HVM: use fixed TSC value when saving or restoring domain
>>> b95fd03 x86/svm: enable TSC scaling
>>> 82713ec x86: use native RDTSC(P) execution when guest and host
>>> frequencies are the same
>> My understanding was that these are solely about performance,
>> not correctness. That would make them weak candidates for
>> 4.4.1 (under the slightly relaxed rules we put on x.y.1 releases),
>> but not any of the older trees. Do you have a different view?
> 
> No, these are correctness fixes.
> 
> The main thing (in this context) about 82713ec is reverting part of 
> 4aab59a3 which broke migration on SVM (in principle I think you can take 
> only the first hunk from it)

I applied this one, ...

> 88e64cb fixes the fact that TSCs get unsynchronized after migration. And 
> it needs some of the interfaces introduced in b95fd03 (which in itself 
> is indeed mostly about performance)

... but didn't take these as being rather large for a problem I don't
recall seeing a report for. If you can see ways to supply a reduced
backport with only the bug fix but not the performance improvement,
feel free to send that for consideration.

Jan


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