[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 06/12] kvmvapic: fixing loading vmstate
From: |
Pavel Dovgaluk |
Subject: |
Re: [Qemu-devel] [PATCH 06/12] kvmvapic: fixing loading vmstate |
Date: |
Tue, 9 Sep 2014 14:30:54 +0400 |
> From: Paolo Bonzini [mailto:address@hidden
> Il 27/08/2014 15:03, Pavel Dovgaluk ha scritto:
> >> > Hmm, probably not. The bug would not be other timers accessing the
> >> > APIC, because that would also call apic_sync_vapic and the only effect
> >> > would be an extra useless synchronization. The bug would happen if the
> >> > APIC is accessed by the CPU before the timer has the occasion to run.
> > Sorry, but I don't understand which problem we will solve with
> > apic_sync_vapic.
>
> Taking inspiration from what KVM does, the fix could be even simpler
> than a change state handler. run_on_cpu functions do not run while the
> VM is stopped, so the following should work:
>
> diff --git a/hw/intc/apic_common.c b/hw/intc/apic_common.c
> index ce3d903..81d1ad7 100644
> --- a/hw/intc/apic_common.c
> +++ b/hw/intc/apic_common.c
> @@ -91,13 +91,20 @@ void apic_enable_tpr_access_reporting(DeviceState
> *dev, bool enable)
> }
> }
>
> +static void do_apic_enable_vapic(void *data)
> +{
> + APICCommonState *s = APIC_COMMON(data);
> + APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
> +
> + info->vapic_base_update(s);
> +}
> +
> void apic_enable_vapic(DeviceState *dev, hwaddr paddr)
> {
> APICCommonState *s = APIC_COMMON(dev);
> - APICCommonClass *info = APIC_COMMON_GET_CLASS(s);
>
> s->vapic_paddr = paddr;
> - info->vapic_base_update(s);
> + run_on_cpu(CPU(s->cpu), do_apic_enable_vapic, s);
> }
I've tried this one and it doesn't work.
do_apic_enable_vapic runs on cpu, at the same time the VM state is loaded.
APIC state still remains broken because of this.
Pavel Dovgalyuk
- Re: [Qemu-devel] [PATCH 06/12] kvmvapic: fixing loading vmstate,
Pavel Dovgaluk <=