Re: [Xen-devel] [PATCH 1/2] x86/pv: Fix bugs with the handling of int80_bounce

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 08.05.17 at 14:54, <andrew.cooper3@xxxxxxxxxx> wrote:
> On 08/05/17 13:39, Jan Beulich wrote:
>>>>> On 08.05.17 at 14:23, <andrew.cooper3@xxxxxxxxxx> wrote:
>>> Overall, I expect that Xenolinux purposefully never asked for an
>>> interrupt gate (as Xen would have rejected that in the 32bit case), and
>>> this point was never considered at all when PVOps was developed, which
>>> followed Linux's normal expectation that int80 was an interrupt gate.
>> Yet I have a hard time seeing why 32-bit Linux needs it to be that
>> way.
> 
> I don't understand what you mean by this.
> 
> Is it a counterpoint to my statement, or just an observation about the
> way Linux chooses to set things up?

Just an observation, including the implication that at least the 32-bit
Linux case has no issue (and quite likely never had one) with us not
masking events despite this having been requested. Otoh it's a little
surprising that 64-bit Linux never had this reported as an issue, as
there's a non-zero chance for its entry code to be hit before the GS
switch.

Jan


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