Re: [PATCH v4 2/3] iommu/vt-d: Track device aux-attach with subdevice_domain_info

[Will Deacon <will@kernel.org>]

On Thu, Jan 07, 2021 at 10:16:57PM +0800, Lu Baolu wrote:
> On 2021/1/7 21:49, Will Deacon wrote:
> > On Thu, Jan 07, 2021 at 12:03:56AM +0800, Liu Yi L wrote:
> > > In the existing code, loop all devices attached to a domain does not
> > > include sub-devices attached via iommu_aux_attach_device().
> > > 
> > > This was found by when I'm working on the below patch, There is no
> > > device in the domain->devices list, thus unable to get the cap and
> > > ecap of iommu unit. But this domain actually has subdevice which is
> > > attached via aux-manner. But it is tracked by domain. This patch is
> > > going to fix it.
> > > 
> > > https://lore.kernel.org/kvm/1599734733-6431-17-git-send-email-yi.l.liu@intel.com/
> > > 
> > > And this fix goes beyond the patch above, such sub-device tracking is
> > > necessary for other cases. For example, flushing device_iotlb for a
> > > domain which has sub-devices attached by auxiliary manner.
> > 
> > Sorry, but I'm having a really hard time understanding what this patch is
> > doing based on this commit message. Baolu -- do you think you could reword
> > it for me please? No need to resend the patch.
> 
> iommu/vt-d: Fix general protection fault in aux_detach_device()

[...]

Thanks! I'll push this out shortly.

Will