[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 2/6] x86_iommu/amd: Prepare for interrupt remap
Re: [Qemu-devel] [PATCH 2/6] x86_iommu/amd: Prepare for interrupt remap support
Thu, 13 Sep 2018 11:15:03 +0800
On Wed, Sep 12, 2018 at 01:59:06PM -0500, Brijesh Singh wrote:
> > > }
> > > return &iommu_as[devfn]->as;
> > > }
> > > @@ -1172,6 +1274,10 @@ static void amdvi_realize(DeviceState *dev, Error
> > > **err)
> > > return;
> > > }
> > > + /* Pseudo address space under root PCI bus. */
> > > + pcms->ioapic_as = amdvi_host_dma_iommu(bus, s, AMDVI_SB_IOAPIC_ID);
> > > + s->intr_enabled = x86_iommu->intr_supported;
> > So does this mean that AMD IR cannot be disabled if declared support?
> > For VT-d, IR needs to be explicitly enabled otherwise disabled (even
> > supported).
> Yes, once its declared as supported then it can not disabled. Its
> upto the guest OS to decide whether it want to use the intr remapping
> feature by parsing the IVRS. This also brings question, should we
> just enable it by default because its guest OS decision whether it
> wants to use it or not.
It's by default off? I mean:
DEFINE_PROP_BOOL("intremap", X86IOMMUState, intr_supported, false),
Then it's good to me, thanks. You could add a comment there
explicitly mentioning that "IR will be enabled as long as declared
support for AMD" since it might confuse some of the people like me...
but it's optional.
Message not available