Gleb Natapov wrote: > On Tue, Feb 16, 2010 at 11:04:10AM +0100, Jan Kiszka wrote: >> Gleb Natapov wrote: >>> On Tue, Feb 16, 2010 at 10:16:12AM +0100, Jan Kiszka wrote: >>>> Found while browsing Xen code: While we assume that the STI interrupt >>>> shadow also inplies virtual NMI blocking, some processors may have a >>>> different opinion (SDM 3: 22.3). To avoid misunderstandings that would >>>> cause endless VM entry attempts, translate STI into MOV SS blocking when >>>> requesting the NMI window. >>>> >>> Why not just remove "block by STI" check in vmx_nmi_allowed()? IIRC this >>> is documented that on some CPUs STI does not block NMI. >>> >> Probably because we will stumble and fall on those CPUs that do care. >> > But this defines behaviour of cpu _we_ emulate. So on _our_ cpu NMI will > not be blocked by STI. The host CPU decides if it accepts an NMI injections while blocked-by-STI is set, not we. But, of course, we could also translate STI into MOV SS blocking unconditionally. Whatever is preferred. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
