Re: [PATCH v9 07/11] iommu/sva: Refactoring iommu_sva_bind/unbind_device()

[Baolu Lu]

On 2022/6/27 18:14, Tian, Kevin wrote:
> > From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Sent: Tuesday, June 21, 2022 10:44 PM
> > +struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct
> > mm_struct *mm)
> > +{
> > +	struct iommu_domain *domain;
> > +	ioasid_t max_pasids;
> > +	int ret = -EINVAL;
> > +
> > +	/* Allocate mm->pasid if necessary. */
>
> this comment is for iommu_sva_alloc_pasid()

Updated.

> > +	max_pasids = dev->iommu->max_pasids;
> > +	if (!max_pasids)
> > +		return ERR_PTR(-EOPNOTSUPP);
> > +
> > +	ret = iommu_sva_alloc_pasid(mm, 1, max_pasids - 1);
> > +	if (ret)
> > +		return ERR_PTR(ret);
> > +
>
>
> ...
> > +void iommu_sva_unbind_device(struct iommu_sva *handle)
> > +{
> > +	struct device *dev = handle->dev;
> > +	struct iommu_domain *domain =
> > +			container_of(handle, struct iommu_domain, bond);
> > +	ioasid_t pasid = iommu_sva_get_pasid(handle);
> > +
> > +	mutex_lock(&iommu_sva_lock);
> > +	if (refcount_dec_and_test(&domain->bond.users)) {
> > +		iommu_detach_device_pasid(domain, dev, pasid);
> > +		iommu_domain_free(domain);
> > +	}
> > +	mutex_unlock(&iommu_sva_lock);
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_sva_unbind_device);
> > +
> > +u32 iommu_sva_get_pasid(struct iommu_sva *handle)
> > +{
> > +	struct iommu_domain *domain =
> > +			container_of(handle, struct iommu_domain, bond);
> > +
> > +	return domain->mm->pasid;
> > +}
> > +EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
>
> Looks this is only used by unbind_device. Just open code it.

It's part of current IOMMU/SVA interfaces for the device drivers, and
has been used in various drivers.

$ git grep iommu_sva_get_pasid
drivers/dma/idxd/cdev.c:                pasid = iommu_sva_get_pasid(sva);
drivers/iommu/iommu-sva-lib.c:  ioasid_t pasid = 
iommu_sva_get_pasid(handle);
drivers/iommu/iommu-sva-lib.c:u32 iommu_sva_get_pasid(struct iommu_sva 
*handle)
drivers/iommu/iommu-sva-lib.c:EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
drivers/misc/uacce/uacce.c:     pasid = iommu_sva_get_pasid(handle);
include/linux/iommu.h:u32 iommu_sva_get_pasid(struct iommu_sva *handle);
include/linux/iommu.h:static inline u32 iommu_sva_get_pasid(struct 
iommu_sva *handle)

Or, I missed anything?

Best regards,
baolu