Hi Baolu, On Wed, 12 Apr 2023 09:37:48 +0800, Baolu Lu <baolu.lu@xxxxxxxxxxxxxxx> wrote: > On 4/11/23 4:02 PM, Tian, Kevin wrote: > >> From: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > >> Sent: Saturday, April 8, 2023 2:06 AM > >> @@ -28,8 +26,8 @@ static int iommu_sva_alloc_pasid(struct mm_struct > >> *mm, ioasid_t min, ioasid_t ma > >> goto out; > >> } > >> > >> - ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, > >> GFP_KERNEL); > >> - if (ret < min) > >> + ret = iommu_alloc_global_pasid(min, max); > > > > I wonder whether this can take a device pointer so > > dev->iommu->max_pasids is enforced inside the alloc function. > > Agreed. Instead of using the open code, it looks better to have a helper > like dev_iommu_max_pasids(). yes, probably export dev_iommu_get_max_pasids(dev)? But if I understood Kevin correctly, he's also suggesting that the interface should be changed to iommu_alloc_global_pasid(dev), my concern is that how do we use this function to reserve RID_PASID which is not specific to a device? > > > > > and do we even need the min/max parameters? With special pasids reserved > > then what driver needs is just to get a free pasid from the global > > space within dev->iommu->max_pasids constraint... > > > > iommu_sva_alloc_pasid() can be reworked to avoid min/max by taking a > > device pointer too. > > Best regards, > baolu Thanks, Jacob
