Re: [RFC v2 1/1] memory: Delete assertion in memory_region_unregister_iommu_notifier

[Jason Wang]

On 2020/6/30 下午11:20, Peter Xu wrote:
> On Tue, Jun 30, 2020 at 05:23:31PM +0800, Jason Wang wrote:
> > > > Ok, we had a dedicated mr for interrupt:
> > > >
> > > > memory_region_add_subregion_overlap(MEMORY_REGION(&vtd_dev_as->iommu),
> > > > VTD_INTERRUPT_ADDR_FIRST,
> > > > &vtd_dev_as->iommu_ir, 1);
> > > >
> > > > So it should be fine. I guess the reason that I'm asking is that I thought
> > > > "IR" means "Interrupt remapping" but in fact it means "Interrupt Region"?
> I was meaning "interrupt remapping", and of course it's the interrupt region
> too when IR enabled...


Right.


> > > > But I'm still not clear about the invalidation part for interrupt region,
> > > > maybe you can elaborate a little more on this.
> > > >
> > > > Btw, I think guest can trigger the assert in vtd_do_iommu_translate() if we
> > > > teach vhost to DMA to that region:
> > > Why would we want to?
> >
> > I meant a buggy(malicious) guest driver.
> Yes seems possible.  Do you want to post a patch?  Let me know if you want me
> to...  Thanks,


Yes please.

Thanks


>