| Message ID | 20180511190641.23008-5-jean-philippe.brucker@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
Hi Jean-Philippe, On 05/11/2018 09:06 PM, Jean-Philippe Brucker wrote: > When an mm exits, devices that were bound to it must stop performing DMA > on its PASID. Let device drivers register a callback to be notified on mm > exit. Add the callback to the sva_param structure attached to struct > device. > > Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> > > --- > v1->v2: use iommu_sva_device_init instead of a separate function > --- > drivers/iommu/iommu-sva.c | 11 ++++++++++- > include/linux/iommu.h | 9 +++++++-- > 2 files changed, 17 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 6ac679c48f3c..0700893c679d 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -303,6 +303,7 @@ static void io_mm_detach_locked(struct iommu_bond *bond) > * @dev: the device > * @features: bitmask of features that need to be initialized > * @max_pasid: max PASID value supported by the device > + * @mm_exit: callback to notify the device driver of an mm exiting > * > * Users of the bind()/unbind() API must call this function to initialize all > * features required for SVA. > @@ -313,13 +314,20 @@ static void io_mm_detach_locked(struct iommu_bond *bond) > * description. Setting @max_pasid to a non-zero value smaller than this limit > * overrides it. > * > + * If the driver intends to share process address spaces, it should pass a valid > + * @mm_exit handler. Otherwise @mm_exit can be NULL. I don't get case where mm_exit is allowed to be NULL. Thanks Eric After @mm_exit returns, the > + * device must not issue any more transaction with the PASID given as argument. > + * The handler gets an opaque pointer corresponding to the drvdata passed as > + * argument of bind(). > + * > * The device should not be performing any DMA while this function is running, > * otherwise the behavior is undefined. > * > * Return 0 if initialization succeeded, or an error. > */ > int iommu_sva_device_init(struct device *dev, unsigned long features, > - unsigned int max_pasid) > + unsigned int max_pasid, > + iommu_mm_exit_handler_t mm_exit) > { > int ret; > struct iommu_sva_param *param; > @@ -337,6 +345,7 @@ int iommu_sva_device_init(struct device *dev, unsigned long features, > > param->features = features; > param->max_pasid = max_pasid; > + param->mm_exit = mm_exit; > INIT_LIST_HEAD(¶m->mm_list); > > /* > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index d5f21719a5a0..439c8fffd836 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -61,6 +61,7 @@ struct iommu_fault_event; > typedef int (*iommu_fault_handler_t)(struct iommu_domain *, > struct device *, unsigned long, int, void *); > typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *, void *); > +typedef int (*iommu_mm_exit_handler_t)(struct device *dev, int pasid, void *); > > struct iommu_domain_geometry { > dma_addr_t aperture_start; /* First address that can be mapped */ > @@ -231,6 +232,7 @@ struct iommu_sva_param { > unsigned int min_pasid; > unsigned int max_pasid; > struct list_head mm_list; > + iommu_mm_exit_handler_t mm_exit; > }; > > /** > @@ -980,17 +982,20 @@ static inline int iommu_sva_unbind_device(struct device *dev, int pasid) > > #ifdef CONFIG_IOMMU_SVA > extern int iommu_sva_device_init(struct device *dev, unsigned long features, > - unsigned int max_pasid); > + unsigned int max_pasid, > + iommu_mm_exit_handler_t mm_exit); > extern int iommu_sva_device_shutdown(struct device *dev); > extern int __iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, > int *pasid, unsigned long flags, > void *drvdata); > extern int __iommu_sva_unbind_device(struct device *dev, int pasid); > extern void __iommu_sva_unbind_dev_all(struct device *dev); > + > #else /* CONFIG_IOMMU_SVA */ > static inline int iommu_sva_device_init(struct device *dev, > unsigned long features, > - unsigned int max_pasid) > + unsigned int max_pasid, > + iommu_mm_exit_handler_t mm_exit) > { > return -ENODEV; > } >
On 05/09/2018 14:23, Auger Eric wrote: >> + * If the driver intends to share process address spaces, it should pass a valid >> + * @mm_exit handler. Otherwise @mm_exit can be NULL. > I don't get case where mm_exit is allowed to be NULL. Right, this comment is a bit premature. Next version adds a "private PASID" patch to allocate private address spaces per PASID (modifiable with map/unmap). That mode doesn't require mm_exit, and I can move the comment there Thanks, Jean
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 6ac679c48f3c..0700893c679d 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -303,6 +303,7 @@ static void io_mm_detach_locked(struct iommu_bond *bond) * @dev: the device * @features: bitmask of features that need to be initialized * @max_pasid: max PASID value supported by the device + * @mm_exit: callback to notify the device driver of an mm exiting * * Users of the bind()/unbind() API must call this function to initialize all * features required for SVA. @@ -313,13 +314,20 @@ static void io_mm_detach_locked(struct iommu_bond *bond) * description. Setting @max_pasid to a non-zero value smaller than this limit * overrides it. * + * If the driver intends to share process address spaces, it should pass a valid + * @mm_exit handler. Otherwise @mm_exit can be NULL. After @mm_exit returns, the + * device must not issue any more transaction with the PASID given as argument. + * The handler gets an opaque pointer corresponding to the drvdata passed as + * argument of bind(). + * * The device should not be performing any DMA while this function is running, * otherwise the behavior is undefined. * * Return 0 if initialization succeeded, or an error. */ int iommu_sva_device_init(struct device *dev, unsigned long features, - unsigned int max_pasid) + unsigned int max_pasid, + iommu_mm_exit_handler_t mm_exit) { int ret; struct iommu_sva_param *param; @@ -337,6 +345,7 @@ int iommu_sva_device_init(struct device *dev, unsigned long features, param->features = features; param->max_pasid = max_pasid; + param->mm_exit = mm_exit; INIT_LIST_HEAD(¶m->mm_list); /* diff --git a/include/linux/iommu.h b/include/linux/iommu.h index d5f21719a5a0..439c8fffd836 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -61,6 +61,7 @@ struct iommu_fault_event; typedef int (*iommu_fault_handler_t)(struct iommu_domain *, struct device *, unsigned long, int, void *); typedef int (*iommu_dev_fault_handler_t)(struct iommu_fault_event *, void *); +typedef int (*iommu_mm_exit_handler_t)(struct device *dev, int pasid, void *); struct iommu_domain_geometry { dma_addr_t aperture_start; /* First address that can be mapped */ @@ -231,6 +232,7 @@ struct iommu_sva_param { unsigned int min_pasid; unsigned int max_pasid; struct list_head mm_list; + iommu_mm_exit_handler_t mm_exit; }; /** @@ -980,17 +982,20 @@ static inline int iommu_sva_unbind_device(struct device *dev, int pasid) #ifdef CONFIG_IOMMU_SVA extern int iommu_sva_device_init(struct device *dev, unsigned long features, - unsigned int max_pasid); + unsigned int max_pasid, + iommu_mm_exit_handler_t mm_exit); extern int iommu_sva_device_shutdown(struct device *dev); extern int __iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, int *pasid, unsigned long flags, void *drvdata); extern int __iommu_sva_unbind_device(struct device *dev, int pasid); extern void __iommu_sva_unbind_dev_all(struct device *dev); + #else /* CONFIG_IOMMU_SVA */ static inline int iommu_sva_device_init(struct device *dev, unsigned long features, - unsigned int max_pasid) + unsigned int max_pasid, + iommu_mm_exit_handler_t mm_exit) { return -ENODEV; }
When an mm exits, devices that were bound to it must stop performing DMA on its PASID. Let device drivers register a callback to be notified on mm exit. Add the callback to the sva_param structure attached to struct device. Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> --- v1->v2: use iommu_sva_device_init instead of a separate function --- drivers/iommu/iommu-sva.c | 11 ++++++++++- include/linux/iommu.h | 9 +++++++-- 2 files changed, 17 insertions(+), 3 deletions(-)