Re: [PATCH] KVM: x86: always exit on EOIs for interrupts listed in the IOAPIC redir table

[Paolo Bonzini]

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? :)

Paolo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/