Re: [Xen-devel] [PATCH 00/11] Alternate p2m: support multiple copies of host p2m

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 15.01.15 at 18:28, <edmund.h.white@xxxxxxxxx> wrote:
> On 01/15/2015 12:16 AM, Jan Beulich wrote:
>>>>> On 14.01.15 at 18:35, <edmund.h.white@xxxxxxxxx> wrote:
>>> Right. The key observation is that at any single point in time, a given
>>> hardware thread can be fetching an instruction or reading data, but not
>>> both.
>> 
>> Fine, as long as an instruction reading itself isn't going to lead to
>> a live lock.
> 
> That's not how the hardware works. By the time you figure out that the
> instruction you are executing reads memory, the instruction itself has
> been fetched and decoded. That won't happen again during this execution.
> 
> That's true for every CPU I've ever seen, not just Intel ones.

Certainly not if either the fetch or the data read faults/vmexits.

Jan


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