Re: [Xen-devel] XSA-60 solutions

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 07.10.13 at 17:08, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> On 07/10/13 16:04, Jan Beulich wrote:
>>>>> On 07.10.13 at 16:29, "Liu, Jinsong" <jinsong.liu@xxxxxxxxx> wrote:
>>> Any comments/suggestions?
>> As pointed out in earlier private conversation, I think that the dual
>> table approach would be preferable if it can be made work.
>>
>> I'm surprised no-one from Oracle responded so far, as it was them
>> originally having found the issue.
> 
> I cant remember whether I asked this before or not, but is there a
> reason why this cant be done in the same way as hypercall continuations?

I think you did; the reason is that we're in the middle of processing
a CR0 write here, and hence can't intermediately exit back to the
guest (which is what we'd do for hypercall continuations). However,
you mentioning this one makes me think whether we couldn't
leverage/extend/clone the MMIO retry logic, or at least deal with
this in ways similar to it (i.e. preventing VM re-entry until processing
is complete). But maybe that would result in even worse hackery...

Jan


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