On Fri, Dec 15, 2023 at 01:50:07AM +0000, Tian, Kevin wrote: > > From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > > Sent: Thursday, December 14, 2023 7:27 PM > > > > On 2023/11/17 21:18, Yi Liu wrote:> This adds the data structure for > > flushing iotlb for the nested domain > > > > +struct iommu_hwpt_vtd_s1_invalidate { > > + __aligned_u64 addr; > > + __aligned_u64 npages; > > + __u32 flags; > > + __u32 __reserved; > > + __u32 error; > > + __u32 dev_id; > > +}; > > > > dev_id is used to report the failed device, userspace should be able to map > > it to a vRID, and inject it to VM as part of ITE/ICE error. > > > > However, I got a problem when trying to get dev_id in cache invalidation > > path, since this is filled in intel iommu driver. Seems like there is no > > good way for it. I've below alternatives to move forward, wish you have > > a look. > > > > - Reuse Nicolin's vRID->pRID mapping. If thevRID->pRID mapping is > > maintained, then intel iommu can report a vRID back to user. But intel > > iommu driver does not have viommu context, no place to hold the vRID- > > >pRID > > mapping. TBH. It may require other reasons to introduce it other than the > > error reporting need. Anyhow, this requires more thinking and also has > > dependency even if it is doable in intel side. > > this sounds like a cleaner way to inject knowledge which iommu driver > requires to find out the user tag. but yes it's a bit weird to introduce > viommu awareness in intel iommu driver when there is no such thing > in real hardware. I think a viommu is defined more like a software object representing the virtual IOMMU in a VM. Since VT-d has a vIOMMU in a nesting case, there could be an object for it too? > and for this error reporting case what we actually require is the > reverse map i.e. pRID->vRID. Not sure whether we can leverage the > same RID mapping uAPI as for ARM/AMD but ignore viommu_id > and then store vRID under device_domain_info. a bit tricky on > life cycle management and also incompatible with SIOV... One thing that I am not very clear here: since both vRID and dev_id are given by the VMM, shouldn't it already know the mapping if the point is to translate (pRID->)dev_id->vRID? Thanks Nicolin