On 2023/12/15 11:32, Nicolin Chen wrote:
On Fri, Dec 15, 2023 at 03:04:44AM +0000, Tian, Kevin wrote:
From: Nicolin Chen <nicolinc@xxxxxxxxxx>
Sent: Friday, December 15, 2023 10:28 AM
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.
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?
it's true for current Qemu.
but there is plan to support Qemu accepting a fd passed by Libvirt.
In that case Qemu even doesn't see the sysfs path hence is not
aware of pRID. otherwise yes we could leave the translation to
VMM instead.
I think I misread Yi's narrative: dev_id is a working approach
for VMM to convert to a vRID, while he is asking for a better
alternative :)
In concept, dev_id works, but in reality we have problem to get a dev_id
for a given device in intel iommu driver, hence I'm asking for help here. :)
--
Regards,
Yi Liu
