| Message ID | 20210916234100.122368-4-logang@deltatee.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Userspace P2PDMA with O_DIRECT NVMe devices | expand |
On Thu, Sep 16, 2021 at 05:40:43PM -0600, Logan Gunthorpe wrote: > pci_p2pdma_map_type() will be needed by the dma-iommu map_sg > implementation because it will need to determine the mapping type > ahead of actually doing the mapping to create the actual iommu mapping. I don't expect this to go via the PCI tree, but if it did I would silently: s/PCI/P2PDMA: make pci_p2pdma_map_type() non-static/ PCI/P2PDMA: Expose pci_p2pdma_map_type()/ s/iommu/IOMMU/ and mention what this patch does in the commit log (in addition to the subject) and fix a couple minor typos below. > Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> > --- > drivers/pci/p2pdma.c | 24 +++++++++++++--------- > include/linux/pci-p2pdma.h | 41 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+), 9 deletions(-) > > diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c > index 1192c465ba6d..b656d8c801a7 100644 > --- a/drivers/pci/p2pdma.c > +++ b/drivers/pci/p2pdma.c > @@ -20,13 +20,6 @@ > #include <linux/seq_buf.h> > #include <linux/xarray.h> > > -enum pci_p2pdma_map_type { > - PCI_P2PDMA_MAP_UNKNOWN = 0, > - PCI_P2PDMA_MAP_NOT_SUPPORTED, > - PCI_P2PDMA_MAP_BUS_ADDR, > - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, > -}; > - > struct pci_p2pdma { > struct gen_pool *pool; > bool p2pmem_published; > @@ -841,8 +834,21 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) > } > EXPORT_SYMBOL_GPL(pci_p2pmem_publish); > > -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > - struct device *dev) > +/** > + * pci_p2pdma_map_type - return the type of mapping that should be used for > + * a given device and pgmap > + * @pgmap: the pagemap of a page to determine the mapping type for > + * @dev: device that is mapping the page > + * > + * Returns one of: > + * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done > + * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address > + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done normally > + * using the CPU physical address (in dma-direct) or an IOVA > + * mapping for the IOMMU. > + */ > +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > + struct device *dev) > { > enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED; > struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; > diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h > index 8318a97c9c61..caac2d023f8f 100644 > --- a/include/linux/pci-p2pdma.h > +++ b/include/linux/pci-p2pdma.h > @@ -16,6 +16,40 @@ > struct block_device; > struct scatterlist; > > +enum pci_p2pdma_map_type { > + /* > + * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping > + * type hasn't been calculated yet. Functions that return this enum > + * never return this value. > + */ > + PCI_P2PDMA_MAP_UNKNOWN = 0, > + > + /* > + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will > + * traverse the host bridge and the host bridge is not in the > + * whitelist. DMA Mapping routines should return an error when > + * this is returned. > + */ > + PCI_P2PDMA_MAP_NOT_SUPPORTED, > + > + /* > + * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to > + * eachother directly through a PCI switch and the transaction will > + * not traverse the host bridge. Such a mapping should program > + * the DMA engine with PCI bus addresses. s/eachother/each other/ > + */ > + PCI_P2PDMA_MAP_BUS_ADDR, > + > + /* > + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk > + * to eachother, but the transaction traverses a host bridge on the > + * whitelist. In this case, a normal mapping either with CPU physical > + * addresses (in the case of dma-direct) or IOVA addresses (in the > + * case of IOMMUs) should be used to program the DMA engine. s/eachother/each other/ > + */ > + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, > +}; > + > #ifdef CONFIG_PCI_P2PDMA > int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, > u64 offset); > @@ -30,6 +64,8 @@ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, > unsigned int *nents, u32 length); > void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); > void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); > +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, > + struct device *dev); > int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, > int nents, enum dma_data_direction dir, unsigned long attrs); > void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, > @@ -83,6 +119,11 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev, > static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) > { > } > +static inline enum pci_p2pdma_map_type > +pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev) > +{ > + return PCI_P2PDMA_MAP_NOT_SUPPORTED; > +} > static inline int pci_p2pdma_map_sg_attrs(struct device *dev, > struct scatterlist *sg, int nents, enum dma_data_direction dir, > unsigned long attrs) > -- > 2.30.2 >
On Thu, Sep 16, 2021 at 05:40:43PM -0600, Logan Gunthorpe wrote: > +enum pci_p2pdma_map_type { > + /* > + * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping > + * type hasn't been calculated yet. Functions that return this enum > + * never return this value. > + */ > + PCI_P2PDMA_MAP_UNKNOWN = 0, > + > + /* > + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will > + * traverse the host bridge and the host bridge is not in the > + * whitelist. DMA Mapping routines should return an error when I gather we are supposed to type allowlist now > + * this is returned. > + */ > + PCI_P2PDMA_MAP_NOT_SUPPORTED, > + > + /* > + * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to > + * eachother directly through a PCI switch and the transaction will 'each other' > + * not traverse the host bridge. Such a mapping should program > + * the DMA engine with PCI bus addresses. > + */ > + PCI_P2PDMA_MAP_BUS_ADDR, > + > + /* > + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk > + * to eachother, but the transaction traverses a host bridge on the 'each other' > + * whitelist. In this case, a normal mapping either with CPU physical > + * addresses (in the case of dma-direct) or IOVA addresses (in the > + * case of IOMMUs) should be used to program the DMA engine. > + */ > + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, > +}; Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Jason
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 1192c465ba6d..b656d8c801a7 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -20,13 +20,6 @@ #include <linux/seq_buf.h> #include <linux/xarray.h> -enum pci_p2pdma_map_type { - PCI_P2PDMA_MAP_UNKNOWN = 0, - PCI_P2PDMA_MAP_NOT_SUPPORTED, - PCI_P2PDMA_MAP_BUS_ADDR, - PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, -}; - struct pci_p2pdma { struct gen_pool *pool; bool p2pmem_published; @@ -841,8 +834,21 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) } EXPORT_SYMBOL_GPL(pci_p2pmem_publish); -static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, - struct device *dev) +/** + * pci_p2pdma_map_type - return the type of mapping that should be used for + * a given device and pgmap + * @pgmap: the pagemap of a page to determine the mapping type for + * @dev: device that is mapping the page + * + * Returns one of: + * PCI_P2PDMA_MAP_NOT_SUPPORTED - The mapping should not be done + * PCI_P2PDMA_MAP_BUS_ADDR - The mapping should use the PCI bus address + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE - The mapping should be done normally + * using the CPU physical address (in dma-direct) or an IOVA + * mapping for the IOMMU. + */ +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, + struct device *dev) { enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED; struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider; diff --git a/include/linux/pci-p2pdma.h b/include/linux/pci-p2pdma.h index 8318a97c9c61..caac2d023f8f 100644 --- a/include/linux/pci-p2pdma.h +++ b/include/linux/pci-p2pdma.h @@ -16,6 +16,40 @@ struct block_device; struct scatterlist; +enum pci_p2pdma_map_type { + /* + * PCI_P2PDMA_MAP_UNKNOWN: Used internally for indicating the mapping + * type hasn't been calculated yet. Functions that return this enum + * never return this value. + */ + PCI_P2PDMA_MAP_UNKNOWN = 0, + + /* + * PCI_P2PDMA_MAP_NOT_SUPPORTED: Indicates the transaction will + * traverse the host bridge and the host bridge is not in the + * whitelist. DMA Mapping routines should return an error when + * this is returned. + */ + PCI_P2PDMA_MAP_NOT_SUPPORTED, + + /* + * PCI_P2PDMA_BUS_ADDR: Indicates that two devices can talk to + * eachother directly through a PCI switch and the transaction will + * not traverse the host bridge. Such a mapping should program + * the DMA engine with PCI bus addresses. + */ + PCI_P2PDMA_MAP_BUS_ADDR, + + /* + * PCI_P2PDMA_MAP_THRU_HOST_BRIDGE: Indicates two devices can talk + * to eachother, but the transaction traverses a host bridge on the + * whitelist. In this case, a normal mapping either with CPU physical + * addresses (in the case of dma-direct) or IOVA addresses (in the + * case of IOMMUs) should be used to program the DMA engine. + */ + PCI_P2PDMA_MAP_THRU_HOST_BRIDGE, +}; + #ifdef CONFIG_PCI_P2PDMA int pci_p2pdma_add_resource(struct pci_dev *pdev, int bar, size_t size, u64 offset); @@ -30,6 +64,8 @@ struct scatterlist *pci_p2pmem_alloc_sgl(struct pci_dev *pdev, unsigned int *nents, u32 length); void pci_p2pmem_free_sgl(struct pci_dev *pdev, struct scatterlist *sgl); void pci_p2pmem_publish(struct pci_dev *pdev, bool publish); +enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap, + struct device *dev); int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs); void pci_p2pdma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg, @@ -83,6 +119,11 @@ static inline void pci_p2pmem_free_sgl(struct pci_dev *pdev, static inline void pci_p2pmem_publish(struct pci_dev *pdev, bool publish) { } +static inline enum pci_p2pdma_map_type +pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev) +{ + return PCI_P2PDMA_MAP_NOT_SUPPORTED; +} static inline int pci_p2pdma_map_sg_attrs(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs)
pci_p2pdma_map_type() will be needed by the dma-iommu map_sg implementation because it will need to determine the mapping type ahead of actually doing the mapping to create the actual iommu mapping. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> --- drivers/pci/p2pdma.c | 24 +++++++++++++--------- include/linux/pci-p2pdma.h | 41 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+), 9 deletions(-)