RE: [PATCH] KVM: x86: always exit on EOIs for interrupts listed in the IOAPIC redir table
From: Zhang, Yang Z
Date: Thu Aug 07 2014 - 02:18:01 EST
Paolo Bonzini wrote on 2014-08-07:
> Il 07/08/2014 03:31, Zhang, Yang Z ha scritto:
>> Let me give an example to see whether my concern is a real problem:
>> Guest allocates a vector and set it in IOAPIC entry to deliver
>> interrupt. Later it masks the IOAPIC entry(means stop the
>> corresponding device) and assign this vector to a MSI device. With
>> this patch, even the vector is not used by IOAPIC, but it still set
>> eoi exit bitmap unconditionally. The subsequent EOIs to MSI device
>> will force vmexit. Could this happen?
>
> Yes, I guess it could. I'm not sure whether it could on Linux or Windows.
>
>> I think the right fixing is to check the ISR plus TMR to construct
>> the eoi exit bitmap.
>
> Do you care enough to propose a patch? :)
>
Sure. I will do it.
> Paolo
Best regards,
Yang
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