Re: [PATCH v5 12/27] iommu/arm-smmu-v3: Start building a generic PASID layer

[Jason Gunthorpe <jgg@nvidia.com>]

On Wed, Mar 20, 2024 at 12:11:36AM +0800, Michael Shavit wrote:
> > @@ -448,19 +446,10 @@ static int __arm_smmu_sva_bind(struct device *dev, ioasid_t pasid,
> >                 goto err_free_bond;
> >         }
> >
> > -       cdptr = arm_smmu_get_cd_ptr(master, mm_get_enqcmd_pasid(mm));
> > -       if (!cdptr) {
> > -               ret = -ENOMEM;
> > -               goto err_put_notifier;
> > -       }
> > -       arm_smmu_make_sva_cd(&target, master, mm, bond->smmu_mn->cd->asid);
> > -       arm_smmu_write_cd_entry(master, pasid, cdptr, &target);
> > -
> > +       arm_smmu_make_sva_cd(target, master, mm, bond->smmu_mn->cd->asid);
> This can probably already move out to arm_smmu_sva_set_dev_pasid in
> this commit. Removing the arm_smmu_get_cd_ptr pre-alloc might also be
> possible if we're careful with failure of arm_smmu_set_pasid.
> This is eventually addressed in "iommu/arm-smmu-v3: Put the SVA mmu
> notifier in the smmu_domain", but that patch is already big enough as
> it is and the change fits nicely here.

Since all this bond related code is going to be deleted I didn't want
to mess with it too much, but sure it looks like this:

static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
				      struct device *dev, ioasid_t id)
{
	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
	struct mm_struct *mm = domain->mm;
	struct arm_smmu_bond *bond;
	struct arm_smmu_cd target;
	int ret;

	if (mm_get_enqcmd_pasid(mm) != id)
		return -EINVAL;

	mutex_lock(&sva_lock);
	bond = __arm_smmu_sva_bind(dev, mm);
	if (IS_ERR(bond)) {
		mutex_unlock(&sva_lock);
		return PTR_ERR(bond);
	}

	arm_smmu_make_sva_cd(&target, master, mm, bond->smmu_mn->cd->asid);
	ret = arm_smmu_set_pasid(master, to_smmu_domain(domain), id, &target);
	if (ret) {
		list_del(&bond->list);
		arm_smmu_mmu_notifier_put(bond->smmu_mn);
		kfree(bond);
		mutex_unlock(&sva_lock);
		return ret;
	}
	mutex_unlock(&sva_lock);
	return 0;
}

Which is much closer to the final arrangment in later patches.

Jason