Marcelo Tosatti 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. > > You still need to state explicitly that mpstate should be written back, > in the reset / vmloads paths. Implicitly by declaring what I called "write-back scope" on cpu_synchronize_state. As the write-back handling is arch-specific, it can also decide what has to be written based on the passed scope, including "mpstate or not". > > The advantage i think is that you unify the save/restore code in vcpu > entry/exit paths. Yep, and that you don't have to teach functions like mon_get_cpu() about kvm's mpstate. Jan
Attachment:
signature.asc
Description: OpenPGP digital signature
