Re: [PATCH 2/2] PCI: vmd: Fix shadow offsets to reflect spec changes

[Derrick, Jonathan]

On Tue, 2019-09-17 at 17:37 +0100, Lorenzo Pieralisi wrote:
> On Tue, Sep 17, 2019 at 03:51:39PM +0000, Derrick, Jonathan wrote:
> 
> [...]
> 
> > Sorry for the confusion.
> > 
> > These changes only affect systems with VMD devices with 8086:28C0
> > device IDs, but these won't be production hardware for some time.
> > 
> > Systems with VMD devices exist in the wild with 8086:201D device IDs.
> > These don't support the guest passthrough mode and this code won't
> > break anything with them. Additionally, patch 1/2 (bus numbering) only
> > affects 8086:28C0.
> > 
> > So on existing HW, these patches won't affect anything
> 
> It is me who created confusion, apologies. I read the code properly and
> I understand that both patches are fixes for HW that is still not
> available (and they can't create an issue with current kernel because
> HAS_MEMBAR_SHADOW and HAS_BUS_RESTRICTIONS features are not implemented
> on 8086:201D), we should take these patches and trickle them to stable
> kernels as soon as possible so that when HW _is_ available mainline and
> stable kernels are fixed.
> 
> Correct ?
> 
> Lorenzo

That's correct. It will apply to 5.2 stable but is missing a few deps
for 4.19 that I wouldn't consider as qualifying as stable. I can
backport to 4.19 fairly easily.


Thanks,
Jon