Hi BaoLu, On Tue, 29 Mar 2022 13:37:52 +0800, Lu Baolu <baolu...@linux.intel.com> wrote:
> Add a new iommu domain type IOMMU_DOMAIN_SVA to represent an I/O page > table which is shared from CPU host VA. Add some helpers to get and > put an SVA domain and implement SVA domain life cycle management. > > Signed-off-by: Lu Baolu <baolu...@linux.intel.com> > --- > include/linux/iommu.h | 7 +++ > drivers/iommu/iommu-sva-lib.h | 10 ++++ > drivers/iommu/iommu-sva-lib.c | 89 +++++++++++++++++++++++++++++++++++ > 3 files changed, 106 insertions(+) > > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 36f43af0af53..29c4c2edd706 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -42,6 +42,7 @@ struct notifier_block; > struct iommu_sva; > struct iommu_fault_event; > struct iommu_dma_cookie; > +struct iommu_sva_cookie; > > /* iommu fault flags */ > #define IOMMU_FAULT_READ 0x0 > @@ -64,6 +65,9 @@ struct iommu_domain_geometry { > #define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped > */ #define __IOMMU_DOMAIN_DMA_FQ (1U << 3) /* DMA-API uses > flush queue */ > +#define __IOMMU_DOMAIN_SHARED (1U << 4) /* Page table shared > from CPU */ +#define __IOMMU_DOMAIN_HOST_VA (1U << 5) /* Host > CPU virtual address */ + > /* > * This are the possible domain-types > * > @@ -86,6 +90,8 @@ struct iommu_domain_geometry { > #define IOMMU_DOMAIN_DMA_FQ (__IOMMU_DOMAIN_PAGING | \ > __IOMMU_DOMAIN_DMA_API | \ > __IOMMU_DOMAIN_DMA_FQ) > +#define IOMMU_DOMAIN_SVA (__IOMMU_DOMAIN_SHARED | \ > + __IOMMU_DOMAIN_HOST_VA) > > struct iommu_domain { > unsigned type; > @@ -95,6 +101,7 @@ struct iommu_domain { > void *handler_token; > struct iommu_domain_geometry geometry; > struct iommu_dma_cookie *iova_cookie; > + struct iommu_sva_cookie *sva_cookie; > }; > > static inline bool iommu_is_dma_domain(struct iommu_domain *domain) > diff --git a/drivers/iommu/iommu-sva-lib.h b/drivers/iommu/iommu-sva-lib.h > index 8909ea1094e3..1a71218b07f5 100644 > --- a/drivers/iommu/iommu-sva-lib.h > +++ b/drivers/iommu/iommu-sva-lib.h > @@ -10,6 +10,7 @@ > > int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t > max); struct mm_struct *iommu_sva_find(ioasid_t pasid); > +struct mm_struct *iommu_sva_domain_mm(struct iommu_domain *domain); > > /* I/O Page fault */ > struct device; > @@ -26,6 +27,8 @@ int iopf_queue_flush_dev(struct device *dev); > struct iopf_queue *iopf_queue_alloc(const char *name); > void iopf_queue_free(struct iopf_queue *queue); > int iopf_queue_discard_partial(struct iopf_queue *queue); > +bool iommu_sva_domain_get_user(struct iommu_domain *domain); > +void iommu_sva_domain_put_user(struct iommu_domain *domain); > > #else /* CONFIG_IOMMU_SVA */ > static inline int iommu_queue_iopf(struct iommu_fault *fault, void > *cookie) @@ -63,5 +66,12 @@ static inline int > iopf_queue_discard_partial(struct iopf_queue *queue) { > return -ENODEV; > } > + > +static inline bool iommu_sva_domain_get_user(struct iommu_domain *domain) > +{ > + return false; > +} > + > +static inline void iommu_sva_domain_put_user(struct iommu_domain > *domain) { } #endif /* CONFIG_IOMMU_SVA */ > #endif /* _IOMMU_SVA_LIB_H */ > diff --git a/drivers/iommu/iommu-sva-lib.c b/drivers/iommu/iommu-sva-lib.c > index 106506143896..78820be23f15 100644 > --- a/drivers/iommu/iommu-sva-lib.c > +++ b/drivers/iommu/iommu-sva-lib.c > @@ -3,12 +3,21 @@ > * Helpers for IOMMU drivers implementing SVA > */ > #include <linux/mutex.h> > +#include <linux/iommu.h> > +#include <linux/slab.h> > #include <linux/sched/mm.h> > > #include "iommu-sva-lib.h" > > static DEFINE_MUTEX(iommu_sva_lock); > static DECLARE_IOASID_SET(iommu_sva_pasid); > +static DEFINE_XARRAY_ALLOC(sva_domain_array); > + > +struct iommu_sva_cookie { > + struct mm_struct *mm; > + ioasid_t pasid; > + refcount_t users; > +}; > > /** > * iommu_sva_alloc_pasid - Allocate a PASID for the mm > @@ -69,3 +78,83 @@ struct mm_struct *iommu_sva_find(ioasid_t pasid) > return ioasid_find(&iommu_sva_pasid, pasid, __mmget_not_zero); > } > EXPORT_SYMBOL_GPL(iommu_sva_find); > + > +static struct iommu_domain * > +iommu_sva_alloc_domain(struct device *dev, struct mm_struct *mm) > +{ > + struct bus_type *bus = dev->bus; > + struct iommu_sva_cookie *cookie; > + struct iommu_domain *domain; > + void *curr; > + > + if (!bus || !bus->iommu_ops) > + return NULL; > + > + cookie = kzalloc(sizeof(*cookie), GFP_KERNEL); > + if (!cookie) > + return NULL; > + > + domain = bus->iommu_ops->domain_alloc(IOMMU_DOMAIN_SVA); > + if (!domain) > + goto err_domain_alloc; > + > + cookie->mm = mm; > + cookie->pasid = mm->pasid; How do you manage the mm life cycle? do you require caller take mm reference? Or this should be limited to the current mm? > + refcount_set(&cookie->users, 1); > + domain->type = IOMMU_DOMAIN_SVA; > + domain->sva_cookie = cookie; > + curr = xa_store(&sva_domain_array, mm->pasid, domain, > GFP_KERNEL); > + if (xa_err(curr)) > + goto err_xa_store; > + > + return domain; > +err_xa_store: > + domain->ops->free(domain); > +err_domain_alloc: > + kfree(cookie); > + return NULL; > +} > + > +static void iommu_sva_free_domain(struct iommu_domain *domain) > +{ > + xa_erase(&sva_domain_array, domain->sva_cookie->pasid); > + kfree(domain->sva_cookie); > + domain->ops->free(domain); > +} > + > +bool iommu_sva_domain_get_user(struct iommu_domain *domain) > +{ > + struct iommu_sva_cookie *cookie = domain->sva_cookie; > + > + return refcount_inc_not_zero(&cookie->users); > +} > + > +void iommu_sva_domain_put_user(struct iommu_domain *domain) > +{ > + struct iommu_sva_cookie *cookie = domain->sva_cookie; > + > + if (refcount_dec_and_test(&cookie->users)) > + iommu_sva_free_domain(domain); > +} > + > +static __maybe_unused struct iommu_domain * > +iommu_sva_get_domain(struct device *dev, struct mm_struct *mm) > +{ > + struct iommu_domain *domain; > + ioasid_t pasid = mm->pasid; > + > + if (pasid == INVALID_IOASID) > + return NULL; > + > + domain = xa_load(&sva_domain_array, pasid); > + if (!domain) > + return iommu_sva_alloc_domain(dev, mm); > + iommu_sva_domain_get_user(domain); > + > + return domain; > +} > + > +struct mm_struct *iommu_sva_domain_mm(struct iommu_domain *domain) > +{ > + return domain->sva_cookie->mm; > +} Thanks, Jacob _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu