Re: [Xen-devel] [PATCH 1/3] Revert "x86/vvmx: fix virtual interrupt injection when Ack on exit control is used"

["Tian, Kevin" <kevin.tian@xxxxxxxxx>]

> From: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> Sent: Monday, March 23, 2020 10:49 PM
> 
> On Mon, Mar 23, 2020 at 09:09:59AM +0100, Jan Beulich wrote:
> > On 20.03.2020 20:07, Roger Pau Monne wrote:
> > > This reverts commit f96e1469ad06b61796c60193daaeb9f8a96d7458.
> > >
> > > The commit is wrong, as the whole point of nvmx_update_apicv is to
> > > update the guest interrupt status field when the Ack on exit VMEXIT
> > > control feature is enabled.
> > >
> > > Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> >
> > Before anyone gets to look at the other two patches, should this
> > be thrown in right away?
> 
> I would like if possible get a confirmation from Kevin (or anyone
> else) that my understanding is correct. I find the nested code very
> confusing, and I've already made a mistake while trying to fix it.
> That being said, this was spotted by osstest as introducing a
> regression, so I guess it's safe to just toss it in now.
> 
> FWIW patch 2/3 attempts to provide a description of my understanding
> of how nvmx_update_apicv works.
> 

I feel it is not good to take this patch alone, as it was introduced to fix
another problem. W/o understanding whether the whole series can
fix both old and new problems, we may risk putting nested interrupt
logic in an even worse state...

Thanks
Kevin