> From: Liu, Yi L <yi.l.liu@xxxxxxxxx> > Sent: Sunday, March 22, 2020 8:32 PM > > From: Liu Yi L <yi.l.liu@xxxxxxxxx> > > This patch adds a module option to make the PASID quota tunable by > administrator. > > TODO: needs to think more on how to make the tuning to be per-process. > > Previous discussions: > https://patchwork.kernel.org/patch/11209429/ > > Cc: Kevin Tian <kevin.tian@xxxxxxxxx> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx> > Cc: Eric Auger <eric.auger@xxxxxxxxxx> > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx> > --- > drivers/vfio/vfio.c | 8 +++++++- > drivers/vfio/vfio_iommu_type1.c | 7 ++++++- > include/linux/vfio.h | 3 ++- > 3 files changed, 15 insertions(+), 3 deletions(-) > > diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c > index d13b483..020a792 100644 > --- a/drivers/vfio/vfio.c > +++ b/drivers/vfio/vfio.c > @@ -2217,13 +2217,19 @@ struct vfio_mm *vfio_mm_get_from_task(struct > task_struct *task) > } > EXPORT_SYMBOL_GPL(vfio_mm_get_from_task); > > -int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max) > +int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int quota, int min, int max) > { > ioasid_t pasid; > int ret = -ENOSPC; > > mutex_lock(&vmm->pasid_lock); > > + /* update quota as it is tunable by admin */ > + if (vmm->pasid_quota != quota) { > + vmm->pasid_quota = quota; > + ioasid_adjust_set(vmm->ioasid_sid, quota); > + } > + It's a bit weird to have quota adjusted in the alloc path, since the latter might be initiated by non-privileged users. Why not doing the simple math in vfio_ create_mm to set the quota when the ioasid set is created? even in the future you may allow per-process quota setting, that should come from separate privileged path instead of thru alloc... > pasid = ioasid_alloc(vmm->ioasid_sid, min, max, NULL); > if (pasid == INVALID_IOASID) { > ret = -ENOSPC; > diff --git a/drivers/vfio/vfio_iommu_type1.c > b/drivers/vfio/vfio_iommu_type1.c > index 331ceee..e40afc0 100644 > --- a/drivers/vfio/vfio_iommu_type1.c > +++ b/drivers/vfio/vfio_iommu_type1.c > @@ -60,6 +60,11 @@ module_param_named(dma_entry_limit, > dma_entry_limit, uint, 0644); > MODULE_PARM_DESC(dma_entry_limit, > "Maximum number of user DMA mappings per container > (65535)."); > > +static int pasid_quota = VFIO_DEFAULT_PASID_QUOTA; > +module_param_named(pasid_quota, pasid_quota, uint, 0644); > +MODULE_PARM_DESC(pasid_quota, > + "Quota of user owned PASIDs per vfio-based application > (1000)."); > + > struct vfio_iommu { > struct list_head domain_list; > struct list_head iova_list; > @@ -2200,7 +2205,7 @@ static int vfio_iommu_type1_pasid_alloc(struct > vfio_iommu *iommu, > goto out_unlock; > } > if (vmm) > - ret = vfio_mm_pasid_alloc(vmm, min, max); > + ret = vfio_mm_pasid_alloc(vmm, pasid_quota, min, max); > else > ret = -EINVAL; > out_unlock: > diff --git a/include/linux/vfio.h b/include/linux/vfio.h > index 75f9f7f1..af2ef78 100644 > --- a/include/linux/vfio.h > +++ b/include/linux/vfio.h > @@ -106,7 +106,8 @@ struct vfio_mm { > > extern struct vfio_mm *vfio_mm_get_from_task(struct task_struct *task); > extern void vfio_mm_put(struct vfio_mm *vmm); > -extern int vfio_mm_pasid_alloc(struct vfio_mm *vmm, int min, int max); > +extern int vfio_mm_pasid_alloc(struct vfio_mm *vmm, > + int quota, int min, int max); > extern int vfio_mm_pasid_free(struct vfio_mm *vmm, ioasid_t pasid); > > /* > -- > 2.7.4
