On Fri, May 2, 2014 at 12:31 PM, Linus Torvalds <torva...@linux-foundation.org> wrote: > > Also, are you *really* sure that "popf" has the same one-instruction > interrupt shadow that "sti" has? Because I'm not at all sure that is > true, and it's not documented as far as I can tell. In contrast, the > one-instruction shadow after "sti" very much _is_ documented.
Yeah, I'm pretty sure about this. The only instructions with an interrupt shadow are "sti", "mov ss" and "pop ss". There may be specific microarchitectures that do it for a "popf" that enables interrupts too, but that is not documented _anywhere_ I could find. Btw, on the "really easy to get wrong in emulation" note and looking at the kernel sources: it looks like KVM gets "pop ss" wrong, and only does the shadow on "mov ss". Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/