Gleb Natapov wrote: > 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. Simple to solve, just add another write-back point: vm_start. Jan
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