Re: [Qemu-devel] [PATCH RFC v3 02/14] intel_iommu: simplify irq region translation

[Tian, Kevin]

> From: Peter Xu [mailto:address@hidden
> Sent: Friday, January 20, 2017 5:05 PM
> 
> On Fri, Jan 20, 2017 at 08:22:14AM +0000, Tian, Kevin wrote:
> > > From: Peter Xu [mailto:address@hidden
> > > Sent: Friday, January 13, 2017 11:06 AM
> > >
> > > Before we have int-remap, we need to bypass interrupt write requests.
> > > That's not necessary now - we have supported int-remap, and all the irq
> > > region requests should be redirected there. Cleaning up the block with
> > > an assertion instead.
> >
> > This comment is not accurate. According to code, the reason why you
> > can do such simplification is because we have standalone memory
> > region now for interrupt addresses. There should be nothing to do
> > with int-remap, which can be disabled by guest... Maybe the standalone
> > region was added when developing int-remap, but functionally they
> > are not related. :-)
> 
> IMHO the above commit message is fairly clear. :-)
> 
> But sure I can add some more emphasise like:
> 
>   "Before we have int-remap memory region, ..."
> 
> Do you think it's okay? Or any better suggestion?
> 
> (Just to mention that even guest disables IR, the MSI region will
>  still be there.)
> 

My option is simple - this patch has nothing to do with int-remap.
It's not necessary, not because we supported int-remap. It's because
we have a standalone memory region for interrupt addresses, as you
described in the code. :-)

Thanks
Kevin