From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH v4 1/1] iommu-api: Add map_sg/unmap_sg functions Date: Tue, 5 Aug 2014 11:13:23 -0400 Message-ID: <20140805151323.GB19709@laptop.dumpdata.com> References: <1406854484-3848-1-git-send-email-ohaugan@codeaurora.org> <1406854484-3848-2-git-send-email-ohaugan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1406854484-3848-2-git-send-email-ohaugan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org> 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: Olav Haugan Cc: linux-arm-msm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, will.deacon-5wv7dgnIgG8@public.gmane.org, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-arm-msm@vger.kernel.org On Thu, Jul 31, 2014 at 05:54:44PM -0700, Olav Haugan wrote: > Mapping and unmapping are more often than not in the critical path. > map_sg and unmap_sg allows IOMMU driver implementations to optimize > the process of mapping and unmapping buffers into the IOMMU page tables. > > Instead of mapping a buffer one page at a time and requiring potentially > expensive TLB operations for each page, this function allows the driver > to map all pages in one go and defer TLB maintenance until after all > pages have been mapped. > > Additionally, the mapping operation would be faster in general since > clients does not have to keep calling map API over and over again for > each physically contiguous chunk of memory that needs to be mapped to a > virtually contiguous region. That is assuming that physical == bus topology. > > Signed-off-by: Olav Haugan > --- > drivers/iommu/iommu.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/iommu.h | 28 ++++++++++++++++++++++++++++ > 2 files changed, 72 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 1698360..1d5dc2e 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1088,6 +1088,50 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) > } > EXPORT_SYMBOL_GPL(iommu_unmap); > > +int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, > + int prot, unsigned long flags) > +{ > + int ret = 0; > + unsigned long offset = 0; > + > + if (unlikely(domain->ops->map_sg == NULL)) { > + unsigned int i; > + struct scatterlist *s; > + > + for_each_sg(sg, s, nents, i) { > + phys_addr_t phys = page_to_phys(sg_page(s)); > + size_t page_len = s->offset + s->length; > + > + ret = iommu_map(domain, iova + offset, phys, page_len, > + prot); > + if (ret) > + goto fail; > + > + offset += page_len; > + } I think it would be better if you had an 'default_iommu_map_sg' with the implementation above. And then the default ops->map_sg would point to that and each IOMMU would over-write with its own version. That way you don't need any of this 'if' and can have the 'iommu_map_sg' be in the header file (either as static inline or an macro). > + } else { > + ret = domain->ops->map_sg(domain, iova, sg, nents, prot, flags); > + } > + goto out; > + > +fail: > + /* undo mappings already done in case of error */ > + iommu_unmap(domain, iova, offset); > +out: > + return ret; > +} > +EXPORT_SYMBOL_GPL(iommu_map_sg); > + > +int iommu_unmap_sg(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags) > +{ > + if (unlikely(domain->ops->unmap_sg == NULL)) > + return iommu_unmap(domain, iova, size); > + else > + return domain->ops->unmap_sg(domain, iova, size, flags); > +} > +EXPORT_SYMBOL_GPL(iommu_unmap_sg); > > int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr, > phys_addr_t paddr, u64 size, int prot) > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 20f9a52..66ad543 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -22,6 +22,7 @@ > #include > #include > #include > +#include > #include > > #define IOMMU_READ (1 << 0) > @@ -93,6 +94,10 @@ enum iommu_attr { > * @detach_dev: detach device from an iommu domain > * @map: map a physically contiguous memory region to an iommu domain > * @unmap: unmap a physically contiguous memory region from an iommu domain > + * @map_sg: map a scatter-gather list of physically contiguous memory chunks > + * to an iommu domain > + * @unmap_sg: unmap a scatter-gather list of physically contiguous memory > + * chunks from an iommu domain > * @iova_to_phys: translate iova to physical address > * @domain_has_cap: domain capabilities query > * @add_device: add device to iommu grouping > @@ -110,6 +115,11 @@ struct iommu_ops { > phys_addr_t paddr, size_t size, int prot); > size_t (*unmap)(struct iommu_domain *domain, unsigned long iova, > size_t size); > + int (*map_sg)(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags); > + int (*unmap_sg)(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags); > phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova); > int (*domain_has_cap)(struct iommu_domain *domain, > unsigned long cap); > @@ -153,6 +163,11 @@ extern int iommu_map(struct iommu_domain *domain, unsigned long iova, > phys_addr_t paddr, size_t size, int prot); > extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, > size_t size); > +extern int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags); > +extern int iommu_unmap_sg(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags); > extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova); > extern int iommu_domain_has_cap(struct iommu_domain *domain, > unsigned long cap); > @@ -287,6 +302,19 @@ static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova, > return -ENODEV; > } > > +static inline int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags) > +{ > + return -ENODEV; > +} > + > +static inline int iommu_unmap_sg(struct iommu_domain *domain, > + unsigned long iova, size_t size, unsigned long flags) > +{ > + return -ENODEV; > +} > + > static inline int iommu_domain_window_enable(struct iommu_domain *domain, > u32 wnd_nr, phys_addr_t paddr, > u64 size, int prot) > -- > The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > > _______________________________________________ > iommu mailing list > iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu From mboxrd@z Thu Jan 1 00:00:00 1970 From: konrad.wilk@oracle.com (Konrad Rzeszutek Wilk) Date: Tue, 5 Aug 2014 11:13:23 -0400 Subject: [PATCH v4 1/1] iommu-api: Add map_sg/unmap_sg functions In-Reply-To: <1406854484-3848-2-git-send-email-ohaugan@codeaurora.org> References: <1406854484-3848-1-git-send-email-ohaugan@codeaurora.org> <1406854484-3848-2-git-send-email-ohaugan@codeaurora.org> Message-ID: <20140805151323.GB19709@laptop.dumpdata.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jul 31, 2014 at 05:54:44PM -0700, Olav Haugan wrote: > Mapping and unmapping are more often than not in the critical path. > map_sg and unmap_sg allows IOMMU driver implementations to optimize > the process of mapping and unmapping buffers into the IOMMU page tables. > > Instead of mapping a buffer one page at a time and requiring potentially > expensive TLB operations for each page, this function allows the driver > to map all pages in one go and defer TLB maintenance until after all > pages have been mapped. > > Additionally, the mapping operation would be faster in general since > clients does not have to keep calling map API over and over again for > each physically contiguous chunk of memory that needs to be mapped to a > virtually contiguous region. That is assuming that physical == bus topology. > > Signed-off-by: Olav Haugan > --- > drivers/iommu/iommu.c | 44 ++++++++++++++++++++++++++++++++++++++++++++ > include/linux/iommu.h | 28 ++++++++++++++++++++++++++++ > 2 files changed, 72 insertions(+) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 1698360..1d5dc2e 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -1088,6 +1088,50 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) > } > EXPORT_SYMBOL_GPL(iommu_unmap); > > +int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, > + int prot, unsigned long flags) > +{ > + int ret = 0; > + unsigned long offset = 0; > + > + if (unlikely(domain->ops->map_sg == NULL)) { > + unsigned int i; > + struct scatterlist *s; > + > + for_each_sg(sg, s, nents, i) { > + phys_addr_t phys = page_to_phys(sg_page(s)); > + size_t page_len = s->offset + s->length; > + > + ret = iommu_map(domain, iova + offset, phys, page_len, > + prot); > + if (ret) > + goto fail; > + > + offset += page_len; > + } I think it would be better if you had an 'default_iommu_map_sg' with the implementation above. And then the default ops->map_sg would point to that and each IOMMU would over-write with its own version. That way you don't need any of this 'if' and can have the 'iommu_map_sg' be in the header file (either as static inline or an macro). > + } else { > + ret = domain->ops->map_sg(domain, iova, sg, nents, prot, flags); > + } > + goto out; > + > +fail: > + /* undo mappings already done in case of error */ > + iommu_unmap(domain, iova, offset); > +out: > + return ret; > +} > +EXPORT_SYMBOL_GPL(iommu_map_sg); > + > +int iommu_unmap_sg(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags) > +{ > + if (unlikely(domain->ops->unmap_sg == NULL)) > + return iommu_unmap(domain, iova, size); > + else > + return domain->ops->unmap_sg(domain, iova, size, flags); > +} > +EXPORT_SYMBOL_GPL(iommu_unmap_sg); > > int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr, > phys_addr_t paddr, u64 size, int prot) > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index 20f9a52..66ad543 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -22,6 +22,7 @@ > #include > #include > #include > +#include > #include > > #define IOMMU_READ (1 << 0) > @@ -93,6 +94,10 @@ enum iommu_attr { > * @detach_dev: detach device from an iommu domain > * @map: map a physically contiguous memory region to an iommu domain > * @unmap: unmap a physically contiguous memory region from an iommu domain > + * @map_sg: map a scatter-gather list of physically contiguous memory chunks > + * to an iommu domain > + * @unmap_sg: unmap a scatter-gather list of physically contiguous memory > + * chunks from an iommu domain > * @iova_to_phys: translate iova to physical address > * @domain_has_cap: domain capabilities query > * @add_device: add device to iommu grouping > @@ -110,6 +115,11 @@ struct iommu_ops { > phys_addr_t paddr, size_t size, int prot); > size_t (*unmap)(struct iommu_domain *domain, unsigned long iova, > size_t size); > + int (*map_sg)(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags); > + int (*unmap_sg)(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags); > phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova); > int (*domain_has_cap)(struct iommu_domain *domain, > unsigned long cap); > @@ -153,6 +163,11 @@ extern int iommu_map(struct iommu_domain *domain, unsigned long iova, > phys_addr_t paddr, size_t size, int prot); > extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, > size_t size); > +extern int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags); > +extern int iommu_unmap_sg(struct iommu_domain *domain, unsigned long iova, > + size_t size, unsigned long flags); > extern phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova); > extern int iommu_domain_has_cap(struct iommu_domain *domain, > unsigned long cap); > @@ -287,6 +302,19 @@ static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova, > return -ENODEV; > } > > +static inline int iommu_map_sg(struct iommu_domain *domain, unsigned long iova, > + struct scatterlist *sg, unsigned int nents, int prot, > + unsigned long flags) > +{ > + return -ENODEV; > +} > + > +static inline int iommu_unmap_sg(struct iommu_domain *domain, > + unsigned long iova, size_t size, unsigned long flags) > +{ > + return -ENODEV; > +} > + > static inline int iommu_domain_window_enable(struct iommu_domain *domain, > u32 wnd_nr, phys_addr_t paddr, > u64 size, int prot) > -- > The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > > _______________________________________________ > iommu mailing list > iommu at lists.linux-foundation.org > https://lists.linuxfoundation.org/mailman/listinfo/iommu