Re: [Qemu-devel] [PATCH] kvm: fix Win2k boot without KVM

[Jan Kiszka <jan.kiszka@web.de>]

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On 2012-11-03 19:56, Blue Swirl wrote:
> On Sat, Nov 3, 2012 at 6:51 PM, Jan Kiszka <jan.kiszka@web.de> wrote:
>> On 2012-11-03 19:49, Blue Swirl wrote:
>>> Ignore accesses to VAPIC when kvmvapic is not enabled.
>>>
>>> Cc: Jan Kiszka <jan.kiszka@web.de>
>>> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
>>> ---
>>>  hw/kvmvapic.c |    7 ++++---
>>>  1 files changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/hw/kvmvapic.c b/hw/kvmvapic.c
>>> index dc111ee..a97d532 100644
>>> --- a/hw/kvmvapic.c
>>> +++ b/hw/kvmvapic.c
>>> @@ -612,6 +612,9 @@ static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
>>>      hwaddr rom_paddr;
>>>      VAPICROMState *s = opaque;
>>>
>>> +    if (!kvm_irqchip_in_kernel()) {
>>> +        return;
>>> +    }
>>>      cpu_synchronize_state(env);
>>>
>>>      /*
>>> @@ -665,9 +668,7 @@ static void vapic_write(void *opaque, hwaddr addr, uint64_t data,
>>>          break;
>>>      default:
>>>      case 4:
>>> -        if (!kvm_irqchip_in_kernel()) {
>>> -            apic_poll_irq(env->apic_state);
>>> -        }
>>> +        apic_poll_irq(env->apic_state);
>>>          break;
>>>      }
>>>  }
>>>
>>
>> NACK, I'm already debugging the true reason (related to code patching).
> 
> This is a minimal fix that lets Win2k boot, now it does not work at
> all. I think it should be applied for 1.3, it can be reverted when
> (if) you find a better fix. There's no hurry though.

If you want to disable it, flip apic.vapic for !kvm_enabled. Your patch
affects user space APIC with KVM as well, though that is perfectly fine.

But first of all give this some days as I just started.

Jan



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