Re: [PATCH v1 02/20] iommu: Introduce a test_dev domain op and an internal helper

Nicolin Chen
2025-10-28T04:38:56Z

On Mon, Oct 27, 2025 at 08:23:10PM -0300, Jason Gunthorpe wrote:
> On Mon, Oct 20, 2025 at 11:51:49AM -0700, Nicolin Chen wrote:
> > On Mon, Oct 20, 2025 at 01:27:36PM -0300, Jason Gunthorpe wrote:
> > > On Sun, Oct 12, 2025 at 05:04:59PM -0700, Nicolin Chen wrote:
> > > > @@ -751,6 +760,8 @@ struct iommu_ops {
> > > > * @free: Release the domain after use.
> > > > */
> > > > struct iommu_domain_ops {
> > > > + int (*test_dev)(struct iommu_domain *domain, struct device *dev,
> > > > + ioasid_t pasid, struct iommu_domain *old);
> > >
> > > Because of the starting remark I'm skeptical that old should be
> > > included here.
> >
> > Hmm, the followings functions sanitizes "old":
> > - qcom_iommu_identity_attach() drivers/iommu/arm/arm-smmu/qcom_iommu.c
>
> That shouldn't be copied over to test??
>
> if (domain == identity_domain || !domain)
> return 0;
>
> That is just optimizing away the attach if it has nothing to do
>
> qcom_domain = to_qcom_iommu_domain(domain);
> if (WARN_ON(!qcom_domain->iommu))
> return -EINVAL;
>
> That can't never happen
>
> > - iommu_sva_set_dev_pasid() in drivers/iommu/amd/pasid.c
>
> Its broken, you are not required by API to detach a domain before
> setting a new one. Keep it in attach, hope someone fixes this driver
> someday.

OK. I am leaving them alone. And no more old passed to test_dev.

Thanks
Nicolin