On Wed, Dec 09, 2009 at 09:09:54PM +0100, Jan Kiszka wrote: > Gleb Natapov wrote: > > On Wed, Dec 09, 2009 at 07:23:38PM +0100, Jan Kiszka wrote: > >> Marcelo Tosatti wrote: > >>> Otherwise a zero apic base is loaded into KVM, which results > >>> in interrupts being lost until a proper apic base with enabled > >>> bit set is loaded. > >>> > >>> Fixes WinXP migration in qemu-kvm origin/next. > >>> > >>> Signed-off-by: Marcelo Tosatti <mtosatti@xxxxxxxxxx> > >>> > >>> diff --git a/hw/apic.c b/hw/apic.c > >>> index 627ff98..45a4d2b 100644 > >>> --- a/hw/apic.c > >>> +++ b/hw/apic.c > >>> @@ -1131,6 +1131,11 @@ int apic_init(CPUState *env) > >>> vmstate_register(s->idx, &vmstate_apic, s); > >>> qemu_register_reset(apic_reset, s); > >>> > >>> + /* apic_reset must be called before the vcpu threads are initialized and load > >>> + * registers, in qemu-kvm. > >>> + */ > >>> + apic_reset(s); > >>> + > >>> local_apics[s->idx] = s; > >>> return 0; > >>> } > >> Heals the issue I saw with Win2003 Server as well. > >> > >> Looks all a bit messy though. Hope we can establish a more regular and > >> less fragile model on the midterm. I wonder if it wouldn't be better to > >> do write-back of the local APIC state along with the register state on > >> vmrun (and only there!). The same would apply to things like mpstate, > > Write back of mp state there is a bug and introduce races. Do write back > > of the whole APIC state there looks like a recipe for disaster. > > Please read the full suggestion: We will only write-back if we were > going through a reset or vmload before. That removes the ugly kvm hooks > from generic code and ensures proper ordering /wrt other write-backs. > IMHO, anything else will continue to cause headache like the above to us. > We can't postpone APIC loading till vmrun. This will race with devices/other vcpus sending interrupts to the vcpu. APIC state of all vcpus should be up-to-date _before_ any vcpu or main loop starts running. -- Gleb. -- 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
