From abe420bfae528c92bd8cc5ecb62dc95672b1fd6f Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 7 Feb 2019 12:59:13 +0100 Subject: swiotlb: Introduce swiotlb_max_mapping_size() The function returns the maximum size that can be remapped by the SWIOTLB implementation. This function will be later exposed to users through the DMA-API. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Christoph Hellwig Signed-off-by: Joerg Roedel Signed-off-by: Michael S. Tsirkin --- include/linux/swiotlb.h | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'include/linux') diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 7c007ed7505f..d3980aeed4a0 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -76,6 +76,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, size_t size, enum dma_data_direction dir, unsigned long attrs); void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); +size_t swiotlb_max_mapping_size(struct device *dev); #else #define swiotlb_force SWIOTLB_NO_FORCE static inline bool is_swiotlb_buffer(phys_addr_t paddr) @@ -95,6 +96,10 @@ static inline unsigned int swiotlb_max_segment(void) { return 0; } +static inline size_t swiotlb_max_mapping_size(struct device *dev) +{ + return SIZE_MAX; +} #endif /* CONFIG_SWIOTLB */ extern void swiotlb_print_info(void); -- cgit v1.2.3 From 492366f7b4237257ef50ca9c431a6a0d50225aca Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 7 Feb 2019 12:59:14 +0100 Subject: swiotlb: Add is_swiotlb_active() function This function will be used from dma_direct code to determine the maximum segment size of a dma mapping. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Christoph Hellwig Signed-off-by: Joerg Roedel Signed-off-by: Michael S. Tsirkin --- include/linux/swiotlb.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'include/linux') diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index d3980aeed4a0..29bc3a203283 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -77,6 +77,7 @@ bool swiotlb_map(struct device *dev, phys_addr_t *phys, dma_addr_t *dma_addr, void __init swiotlb_exit(void); unsigned int swiotlb_max_segment(void); size_t swiotlb_max_mapping_size(struct device *dev); +bool is_swiotlb_active(void); #else #define swiotlb_force SWIOTLB_NO_FORCE static inline bool is_swiotlb_buffer(phys_addr_t paddr) @@ -100,6 +101,11 @@ static inline size_t swiotlb_max_mapping_size(struct device *dev) { return SIZE_MAX; } + +static inline bool is_swiotlb_active(void) +{ + return false; +} #endif /* CONFIG_SWIOTLB */ extern void swiotlb_print_info(void); -- cgit v1.2.3 From 133d624b1cee16906134e92d5befb843b58bcf31 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 7 Feb 2019 12:59:15 +0100 Subject: dma: Introduce dma_max_mapping_size() The function returns the maximum size that can be mapped using DMA-API functions. The patch also adds the implementation for direct DMA and a new dma_map_ops pointer so that other implementations can expose their limit. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Christoph Hellwig Signed-off-by: Joerg Roedel Signed-off-by: Michael S. Tsirkin --- include/linux/dma-mapping.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux') diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index f6ded992c183..5b21f14802e1 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -130,6 +130,7 @@ struct dma_map_ops { enum dma_data_direction direction); int (*dma_supported)(struct device *dev, u64 mask); u64 (*get_required_mask)(struct device *dev); + size_t (*max_mapping_size)(struct device *dev); }; #define DMA_MAPPING_ERROR (~(dma_addr_t)0) @@ -257,6 +258,8 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev, } #endif +size_t dma_direct_max_mapping_size(struct device *dev); + #ifdef CONFIG_HAS_DMA #include @@ -460,6 +463,7 @@ int dma_supported(struct device *dev, u64 mask); int dma_set_mask(struct device *dev, u64 mask); int dma_set_coherent_mask(struct device *dev, u64 mask); u64 dma_get_required_mask(struct device *dev); +size_t dma_max_mapping_size(struct device *dev); #else /* CONFIG_HAS_DMA */ static inline dma_addr_t dma_map_page_attrs(struct device *dev, struct page *page, size_t offset, size_t size, @@ -561,6 +565,10 @@ static inline u64 dma_get_required_mask(struct device *dev) { return 0; } +static inline size_t dma_max_mapping_size(struct device *dev) +{ + return 0; +} #endif /* CONFIG_HAS_DMA */ static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr, -- cgit v1.2.3 From e6d6dd6c875eb3c9b69bb640419405726e6e0bbe Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Thu, 7 Feb 2019 12:59:16 +0100 Subject: virtio: Introduce virtio_max_dma_size() This function returns the maximum segment size for a single dma transaction of a virtio device. The possible limit comes from the SWIOTLB implementation in the Linux kernel, that has an upper limit of (currently) 256kb of contiguous memory it can map. Other DMA-API implementations might also have limits. Use the new dma_max_mapping_size() function to determine the maximum mapping size when DMA-API is in use for virtio. Cc: stable@vger.kernel.org Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Christoph Hellwig Signed-off-by: Joerg Roedel Signed-off-by: Michael S. Tsirkin --- include/linux/virtio.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/virtio.h b/include/linux/virtio.h index fa1b5da2804e..673fe3ef3607 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -157,6 +157,8 @@ int virtio_device_freeze(struct virtio_device *dev); int virtio_device_restore(struct virtio_device *dev); #endif +size_t virtio_max_dma_size(struct virtio_device *vdev); + #define virtio_device_for_each_vq(vdev, vq) \ list_for_each_entry(vq, &vdev->vqs, list) -- cgit v1.2.3 From ab7a2375fb8e83f8744c34442f476fa5a9df5e35 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Thu, 31 Jan 2019 13:53:14 +0100 Subject: virtio: hint if callbacks surprisingly might sleep A virtio transport is free to implement some of the callbacks in virtio_config_ops in a matter that they cannot be called from atomic context (e.g. virtio-ccw, which maps a lot of the callbacks to channel I/O, which is an inherently asynchronous mechanism). This can be very surprising for developers using the much more common virtio-pci transport, just to find out that things break when used on s390. The documentation for virtio_config_ops now contains a comment explaining this, but it makes sense to add a might_sleep() annotation to various wrapper functions in the virtio core to avoid surprises later. Note that annotations are NOT added to two classes of calls: - direct calls from device drivers (all current callers should be fine, however) - calls which clearly won't be made from atomic context (such as those ultimately coming in via the driver core) Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin --- include/linux/virtio_config.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'include/linux') diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h index 987b6491b946..bb4cc4910750 100644 --- a/include/linux/virtio_config.h +++ b/include/linux/virtio_config.h @@ -290,6 +290,7 @@ static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) /* Config space accessors. */ #define virtio_cread(vdev, structname, member, ptr) \ do { \ + might_sleep(); \ /* Must match the member's type, and be integer */ \ if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ (*ptr) = 1; \ @@ -319,6 +320,7 @@ static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) /* Config space accessors. */ #define virtio_cwrite(vdev, structname, member, ptr) \ do { \ + might_sleep(); \ /* Must match the member's type, and be integer */ \ if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ BUG_ON((*ptr) == 1); \ @@ -358,6 +360,7 @@ static inline void __virtio_cread_many(struct virtio_device *vdev, vdev->config->generation(vdev) : 0; int i; + might_sleep(); do { old = gen; @@ -380,6 +383,8 @@ static inline void virtio_cread_bytes(struct virtio_device *vdev, static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) { u8 ret; + + might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return ret; } @@ -387,6 +392,7 @@ static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) static inline void virtio_cwrite8(struct virtio_device *vdev, unsigned int offset, u8 val) { + might_sleep(); vdev->config->set(vdev, offset, &val, sizeof(val)); } @@ -394,6 +400,8 @@ static inline u16 virtio_cread16(struct virtio_device *vdev, unsigned int offset) { u16 ret; + + might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return virtio16_to_cpu(vdev, (__force __virtio16)ret); } @@ -401,6 +409,7 @@ static inline u16 virtio_cread16(struct virtio_device *vdev, static inline void virtio_cwrite16(struct virtio_device *vdev, unsigned int offset, u16 val) { + might_sleep(); val = (__force u16)cpu_to_virtio16(vdev, val); vdev->config->set(vdev, offset, &val, sizeof(val)); } @@ -409,6 +418,8 @@ static inline u32 virtio_cread32(struct virtio_device *vdev, unsigned int offset) { u32 ret; + + might_sleep(); vdev->config->get(vdev, offset, &ret, sizeof(ret)); return virtio32_to_cpu(vdev, (__force __virtio32)ret); } @@ -416,6 +427,7 @@ static inline u32 virtio_cread32(struct virtio_device *vdev, static inline void virtio_cwrite32(struct virtio_device *vdev, unsigned int offset, u32 val) { + might_sleep(); val = (__force u32)cpu_to_virtio32(vdev, val); vdev->config->set(vdev, offset, &val, sizeof(val)); } @@ -431,6 +443,7 @@ static inline u64 virtio_cread64(struct virtio_device *vdev, static inline void virtio_cwrite64(struct virtio_device *vdev, unsigned int offset, u64 val) { + might_sleep(); val = (__force u64)cpu_to_virtio64(vdev, val); vdev->config->set(vdev, offset, &val, sizeof(val)); } -- cgit v1.2.3