Re: [Xen-devel] [PATCH 3/3] domctl: pause vCPU for context reads

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 05.02.14 at 16:29, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> On 05/02/14 14:54, Jan Beulich wrote:
>> "Base" context reads already paused the subject vCPU when being the
>> current one, but that special case isn't being properly dealt with
>> anyway (at the very least when x86's fsgsbase feature is in use), so
>> just disallow it.
>>
>> "Extended" context reads so far didn't do any pausing.
>>
>> While we can't avoid the reported data being stale by the time it
>> arrives at the caller, this way we at least guarantee that it is
>> consistent.
>>
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> 
> Now I come to think about it, is this an ABI change, as we are now
> disallowing a control domain to issue these hypercalls on itself?

Of course it is, and intentionally so. As was patch 2. And imo it
was never correct to allow this.

Jan


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