Re: [Xen-devel] [PATCH] xen svm: fix PAUSE instruction intercept

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

>>> On 12.08.10 at 11:22, Christoph Egger <Christoph.Egger@xxxxxxx> wrote:
> In svm_vmexit_do_pause() update the instruction pointer.
> This fixes strange PAUSE intercepts on UP guests.

This won't work when the instruction needs to actually be decoded:
__get_instruction_length_from_list() strips all prefix bytes from
the byte stream being decoded, and since 'pause' uses a prefix the
actual opcode comparison will never produce a match.

Even in the case that CPUs supporting the pause filter would always
support nextrip I think that the special case minimally deserves a
code comment to that effect, but perhaps even warrants an
ASSERT() or BUG_ON().

Jan


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