From mboxrd@z Thu Jan 1 00:00:00 1970 From: Auger Eric Subject: Re: [PATCH v2 04/40] iommu/sva: Add a mm_exit callback for device drivers Date: Wed, 5 Sep 2018 15:23:34 +0200 Message-ID: References: <20180511190641.23008-1-jean-philippe.brucker@arm.com> <20180511190641.23008-5-jean-philippe.brucker@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180511190641.23008-5-jean-philippe.brucker-5wv7dgnIgG8@public.gmane.org> Content-Language: en-US List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Jean-Philippe Brucker , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org Cc: xieyisheng1-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, ilias.apalodimas-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, xuzaibo-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, okaya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, ashok.raj-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, rfranz-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org, kevin.tian-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, rgummal-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org, dwmw2-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, liubo95-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, robin.murphy-5wv7dgnIgG8@public.gmane.org, christian.koenig-5C7GfCeVMHo@public.gmane.org List-Id: iommu@lists.linux-foundation.org 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 > > --- > 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; > } >