Re: [PATCH v7 2/7] iommu/sva: Move PASID helpers to sva code

Jacob Pan
2023-03-20T20:48:05Z

Hi Jason,

On Mon, 20 Mar 2023 16:11:10 -0300, Jason Gunthorpe <jgg@nvidia.com> wrote:

> On Mon, Mar 20, 2023 at 11:59:05AM -0700, Jacob Pan wrote:
> > Preparing to remove IOASID infrastructure, PASID management will be
> > under SVA code. Decouple mm code from IOASID.
> >
> > Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> > ---
> > v7:
> > - use CONFIG_IOMMU_SVA around PASID helpers in fork.c, Fixes a
> > compile problem.
> > v6:
> > - put helpers under iommu.h instead of iommu-helper.h
> > v5:
> > - move definition of helpers to iommu code to be consistent with
> > declarations. (Kevin)
> > - fix patch partitioning bug (Baolu)
> > v4:
> > - delete and open code mm_set_pasid
> > - keep mm_init_pasid() as inline for fork performance
> > ---
> > drivers/iommu/iommu-sva.c | 10 +++++++++-
> > include/linux/ioasid.h | 6 +-----
> > include/linux/iommu.h | 14 +++++++++++++-
> > include/linux/sched/mm.h | 26 --------------------------
> > kernel/fork.c | 5 +++++
> > 5 files changed, 28 insertions(+), 33 deletions(-)
> >
> > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
> > index 24bf9b2b58aa..fcfdc80a3939 100644
> > --- a/drivers/iommu/iommu-sva.c
> > +++ b/drivers/iommu/iommu-sva.c
> > @@ -44,7 +44,7 @@ int iommu_sva_alloc_pasid(struct mm_struct *mm,
> > ioasid_t min, ioasid_t max) if (!pasid_valid(pasid))
> > ret = -ENOMEM;
> > else
> > - mm_pasid_set(mm, pasid);
> > + mm->pasid = pasid;
> > out:
> > mutex_unlock(&iommu_sva_lock);
> > return ret;
> > @@ -238,3 +238,11 @@ iommu_sva_handle_iopf(struct iommu_fault *fault,
> > void *data)
> > return status;
> > }
> > +
> > +void mm_pasid_drop(struct mm_struct *mm)
> > +{
> > + if (pasid_valid(mm->pasid)) {
> > + ioasid_free(mm->pasid);
> > + mm->pasid = INVALID_IOASID;
> > + }
> > +}
> > diff --git a/include/linux/ioasid.h b/include/linux/ioasid.h
> > index af1c9d62e642..bdee937da907 100644
> > --- a/include/linux/ioasid.h
> > +++ b/include/linux/ioasid.h
> > @@ -4,8 +4,8 @@
> >
> > #include <linux/types.h>
> > #include <linux/errno.h>
> > +#include <linux/iommu.h>
> >
> > -#define INVALID_IOASID ((ioasid_t)-1)
> > typedef unsigned int ioasid_t;
> > typedef ioasid_t (*ioasid_alloc_fn_t)(ioasid_t min, ioasid_t max, void
> > *data); typedef void (*ioasid_free_fn_t)(ioasid_t ioasid, void *data);
> > @@ -40,10 +40,6 @@ void *ioasid_find(struct ioasid_set *set, ioasid_t
> > ioasid, int ioasid_register_allocator(struct ioasid_allocator_ops
> > *allocator); void ioasid_unregister_allocator(struct
> > ioasid_allocator_ops *allocator); int ioasid_set_data(ioasid_t ioasid,
> > void *data); -static inline bool pasid_valid(ioasid_t ioasid)
> > -{
> > - return ioasid != INVALID_IOASID;
> > -}
> >
> > #else /* !CONFIG_IOASID */
> > static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t
> > min, diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 6595454d4f48..d3f81dc6e4dd 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -13,7 +13,6 @@
> > #include <linux/errno.h>
> > #include <linux/err.h>
> > #include <linux/of.h>
> > -#include <linux/ioasid.h>
> > #include <uapi/linux/iommu.h>
> >
> > #define IOMMU_READ (1 << 0)
> > @@ -192,6 +191,8 @@ enum iommu_dev_features {
> > };
> >
> > #define IOMMU_PASID_INVALID (-1U)
> > +typedef unsigned int ioasid_t;
> > +#define INVALID_IOASID ((ioasid_t)-1)
> >
> > #ifdef CONFIG_IOMMU_API
> >
> > @@ -1172,7 +1173,16 @@ static inline bool
> > tegra_dev_iommu_get_stream_id(struct device *dev, u32 *stream return
> > false; }
> >
> > +static inline bool pasid_valid(ioasid_t ioasid)
> > +{
> > + return ioasid != INVALID_IOASID;
> > +}
> > #ifdef CONFIG_IOMMU_SVA
> > +static inline void mm_pasid_init(struct mm_struct *mm)
> > +{
> > + mm->pasid = INVALID_IOASID;
> > +}
> > +void mm_pasid_drop(struct mm_struct *mm);
> > struct iommu_sva *iommu_sva_bind_device(struct device *dev,
> > struct mm_struct *mm);
> > void iommu_sva_unbind_device(struct iommu_sva *handle);
> > @@ -1192,6 +1202,8 @@ static inline u32 iommu_sva_get_pasid(struct
> > iommu_sva *handle) {
> > return IOMMU_PASID_INVALID;
> > }
> > +static inline void mm_pasid_init(struct mm_struct *mm) {}
> > +static inline void mm_pasid_drop(struct mm_struct *mm) {}
> > #endif /* CONFIG_IOMMU_SVA */
> >
> > #endif /* __LINUX_IOMMU_H */
> > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
> > index 2a243616f222..da9712a3ba73 100644
> > --- a/include/linux/sched/mm.h
> > +++ b/include/linux/sched/mm.h
> > @@ -8,7 +8,6 @@
> > #include <linux/mm_types.h>
> > #include <linux/gfp.h>
> > #include <linux/sync_core.h>
> > -#include <linux/ioasid.h>
> >
> > /*
> > * Routines for handling mm_structs
> > @@ -451,29 +450,4 @@ static inline void
> > membarrier_update_current_mm(struct mm_struct *next_mm) }
> > #endif
> >
> > -#ifdef CONFIG_IOMMU_SVA
> > -static inline void mm_pasid_init(struct mm_struct *mm)
> > -{
> > - mm->pasid = INVALID_IOASID;
> > -}
> > -
> > -/* Associate a PASID with an mm_struct: */
> > -static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid)
> > -{
> > - mm->pasid = pasid;
> > -}
> > -
> > -static inline void mm_pasid_drop(struct mm_struct *mm)
> > -{
> > - if (pasid_valid(mm->pasid)) {
> > - ioasid_free(mm->pasid);
> > - mm->pasid = INVALID_IOASID;
> > - }
> > -}
> > -#else
> > -static inline void mm_pasid_init(struct mm_struct *mm) {}
> > -static inline void mm_pasid_set(struct mm_struct *mm, u32 pasid) {}
> > -static inline void mm_pasid_drop(struct mm_struct *mm) {}
> > -#endif
>
>
> > @@ -794,7 +795,9 @@ void __mmdrop(struct mm_struct *mm)
> > mmu_notifier_subscriptions_destroy(mm);
> > check_mm(mm);
> > put_user_ns(mm->user_ns);
> > +#ifdef CONFIG_IOMMU_SVA
> > mm_pasid_drop(mm);
> > +#endif
> >
> > for (i = 0; i < NR_MM_COUNTERS; i++)
> > percpu_counter_destroy(&mm->rss_stat[i]);
> > @@ -1140,7 +1143,9 @@ static struct mm_struct *mm_init(struct mm_struct
> > *mm, struct task_struct *p, mm_init_cpumask(mm);
> > mm_init_aio(mm);
> > mm_init_owner(mm, p);
> > +#ifdef CONFIG_IOMMU_SVA
> > mm_pasid_init(mm);
> > +#endif
>
> No ifdef here, you correctly made static inline dummy functions above.
right, will remove them.

Thanks,

Jacob