On Fri, 27 Mar 2020 10:09:04 +0000 "Tian, Kevin" <[email protected]> wrote:
> > From: Jacob Pan <[email protected]> > > Sent: Thursday, March 26, 2020 1:56 AM > > > > IOASID set is allocated with an initial quota, at runtime there may > > be needs to balance IOASID resources among different VMs/sets. > > > > I may overlook previous patches but I didn't see any place setting the > initial quota... > Initial quota is in place when the ioasid_set is allocated. > > This patch adds a new API to adjust per set quota. > > since this is purely an internal kernel API, implies that the > publisher (e.g. VFIO) is responsible for exposing its own uAPI to set > the quota? > yes, VFIO will do the adjustment. I think Alex suggested module parameters. > > > > Signed-off-by: Jacob Pan <[email protected]> > > --- > > drivers/iommu/ioasid.c | 44 > > ++++++++++++++++++++++++++++++++++++++++++++ > > include/linux/ioasid.h | 6 ++++++ > > 2 files changed, 50 insertions(+) > > > > diff --git a/drivers/iommu/ioasid.c b/drivers/iommu/ioasid.c > > index 27dce2cb5af2..5ac28862a1db 100644 > > --- a/drivers/iommu/ioasid.c > > +++ b/drivers/iommu/ioasid.c > > @@ -578,6 +578,50 @@ void ioasid_free_set(int sid, bool destroy_set) > > } > > EXPORT_SYMBOL_GPL(ioasid_free_set); > > > > +/** > > + * ioasid_adjust_set - Adjust the quota of an IOASID set > > + * @quota: Quota allowed in this set > > + * @sid: IOASID set ID to be assigned > > + * > > + * Return 0 on success. If the new quota is smaller than the > > number of > > + * IOASIDs already allocated, -EINVAL will be returned. No change > > will be > > + * made to the existing quota. > > + */ > > +int ioasid_adjust_set(int sid, int quota) > > +{ > > + struct ioasid_set_data *sdata; > > + int ret = 0; > > + > > + mutex_lock(&ioasid_allocator_lock); > > + sdata = xa_load(&ioasid_sets, sid); > > + if (!sdata || sdata->nr_ioasids > quota) { > > + pr_err("Failed to adjust IOASID set %d quota %d\n", > > + sid, quota); > > + ret = -EINVAL; > > + goto done_unlock; > > + } > > + > > + if (quota >= ioasid_capacity_avail) { > > + ret = -ENOSPC; > > + goto done_unlock; > > + } > > + > > + /* Return the delta back to system pool */ > > + ioasid_capacity_avail += sdata->size - quota; > > + > > + /* > > + * May have a policy to prevent giving all available > > IOASIDs > > + * to one set. But we don't enforce here, it should be in > > the > > + * upper layers. > > + */ > > + sdata->size = quota; > > + > > +done_unlock: > > + mutex_unlock(&ioasid_allocator_lock); > > + > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(ioasid_adjust_set); > > > > /** > > * ioasid_find - Find IOASID data > > diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h > > index 32d032913828..6e7de6fb91bf 100644 > > --- a/include/linux/ioasid.h > > +++ b/include/linux/ioasid.h > > @@ -73,6 +73,7 @@ int ioasid_alloc_set(struct ioasid_set *token, > > ioasid_t quota, int *sid); > > void ioasid_free_set(int sid, bool destroy_set); > > int ioasid_find_sid(ioasid_t ioasid); > > int ioasid_notify(ioasid_t id, enum ioasid_notify_val cmd); > > +int ioasid_adjust_set(int sid, int quota); > > > > #else /* !CONFIG_IOASID */ > > static inline ioasid_t ioasid_alloc(int sid, ioasid_t min, > > @@ -136,5 +137,10 @@ static inline int ioasid_alloc_system_set(int > > quota) return -ENOTSUPP; > > } > > > > +static inline int ioasid_adjust_set(int sid, int quota) > > +{ > > + return -ENOTSUPP; > > +} > > + > > #endif /* CONFIG_IOASID */ > > #endif /* __LINUX_IOASID_H */ > > -- > > 2.7.4 > [Jacob Pan] _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
