From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lu Baolu Subject: Re: [PATCH v3 06/10] iommu/sva: Search mm by PASID Date: Tue, 25 Sep 2018 12:59:33 +0800 Message-ID: References: <20180920170046.20154-1-jean-philippe.brucker@arm.com> <20180920170046.20154-7-jean-philippe.brucker@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180920170046.20154-7-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 , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Cc: kevin.tian-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, ashok.raj-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ilias.apalodimas-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, okaya-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, liguozhu-C8/M+/jPZTeaMJb+Lgu22Q@public.gmane.org, robin.murphy-5wv7dgnIgG8@public.gmane.org, christian.koenig-5C7GfCeVMHo@public.gmane.org List-Id: iommu@lists.linux-foundation.org Hi, On 09/21/2018 01:00 AM, Jean-Philippe Brucker wrote: > The fault handler will need to find an mm given its PASID. This is the > reason we have an IDR for storing address spaces, so hook it up. > > Signed-off-by: Jean-Philippe Brucker > --- > drivers/iommu/iommu-sva.c | 26 ++++++++++++++++++++++++++ > include/linux/iommu.h | 7 +++++++ > 2 files changed, 33 insertions(+) > > diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c > index 5ff8967cb213..ee86f00ee1b9 100644 > --- a/drivers/iommu/iommu-sva.c > +++ b/drivers/iommu/iommu-sva.c > @@ -636,6 +636,32 @@ void iommu_sva_unbind_device_all(struct device *dev) > } > EXPORT_SYMBOL_GPL(iommu_sva_unbind_device_all); > > +/** > + * iommu_sva_find() - Find mm associated to the given PASID > + * @pasid: Process Address Space ID assigned to the mm > + * > + * Returns the mm corresponding to this PASID, or NULL if not found. A reference > + * to the mm is taken, and must be released with mmput(). > + */ > +struct mm_struct *iommu_sva_find(int pasid) > +{ > + struct io_mm *io_mm; > + struct mm_struct *mm = NULL; > + > + spin_lock(&iommu_sva_lock); > + io_mm = idr_find(&iommu_pasid_idr, pasid); The same thing here. We can't guarantee that a pointer of mm_struct type is associated with a pasid value when pasid is also used for other purposes. If hardware reports a bad pasid, this function might run into problem. Best regards, Lu Baolu > + if (io_mm && io_mm_get_locked(io_mm)) { > + if (mmget_not_zero(io_mm->mm)) > + mm = io_mm->mm; > + > + io_mm_put_locked(io_mm); > + } > + spin_unlock(&iommu_sva_lock); > + > + return mm; > +} > +EXPORT_SYMBOL_GPL(iommu_sva_find); > + > /** > * iommu_sva_init_device() - Initialize Shared Virtual Addressing for a device > * @dev: the device > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 429f3dc37a35..a457650b80de 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -987,6 +987,8 @@ extern int __iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, > void *drvdata); > extern int __iommu_sva_unbind_device(struct device *dev, int pasid); > extern void iommu_sva_unbind_device_all(struct device *dev); > +extern struct mm_struct *iommu_sva_find(int pasid); > + > #else /* CONFIG_IOMMU_SVA */ > static inline int iommu_sva_init_device(struct device *dev, > unsigned long features, > @@ -1016,6 +1018,11 @@ static inline int __iommu_sva_unbind_device(struct device *dev, int pasid) > static inline void iommu_sva_unbind_device_all(struct device *dev) > { > } > + > +static inline struct mm_struct *iommu_sva_find(int pasid) > +{ > + return NULL; > +} > #endif /* CONFIG_IOMMU_SVA */ > > #endif /* __LINUX_IOMMU_H */ >