On 08/27/2010 11:27 AM, Jan Kiszka wrote:
Am 26.08.2010 22:06, Jes.Sorensen@xxxxxxxxxx wrote:
From: Jes Sorensen<Jes.Sorensen@xxxxxxxxxx>
Injecting an NMI while GUEST_INTR_STATE_STI is set may fail,
which can cause an EXIT with invalid state, resulting in the
guest dieing.
Very interesting. Reality obviously doesn't bother about the statement
of the vendor [1].
Just curious: is this limited to specific CPU models or actually a
generic issue?
The manual states that whether a processor accepts NMIs when
blocked-by-STI or not is processor dependent.
Thinking about the implications: Independent of virtualization, this
means that no code code can in any way rely on the STI shadow if there
are NMIs present that could "consume" it. Because after return from
those NMIs, interrupts could then be injected on the instruction that
was originally under the shadow.
Wow. Maybe we should request an interrupt window instead when
blocked-by-STI is active instead of clearing it.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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