RE: [PATCH v1 14/14] iommu/arm-smmu-v3: Add arm_smmu_cache_invalidate_user

Tian, Kevin
2023-03-24T08:56:41Z

> From: Nicolin Chen <nicolinc@nvidia.com>
> Sent: Wednesday, March 22, 2023 1:15 PM
>
> >
> > Something has to generate CMD_ATC_INV.
> >
> > How do you plan to generate this from the hypervisor based on ASID
> > invalidations?
> >
> > The hypervisor doesn't know what ASIDs are connected to what SIDs to
> > generate the ATC?
> >
> > Intel is different, they know what devices the vDID is connected to,
> > so when they get a vDID invalidation they can elaborate it into a ATC
> > invalidation. ARM doesn't have that information.
>
> I see. Perhaps vSMMU still needs to forward CMD_ATC_INV. And,

Ah that's quite a different story. 😊