| Message ID | 20210616035240.840463-10-tientzu@chromium.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Restricted DMA | expand |
On Wed, Jun 16, 2021 at 11:54 AM Claire Chang <tientzu@chromium.org> wrote: > > Add the functions, swiotlb_{alloc,free} to support the memory allocation > from restricted DMA pool. > > The restricted DMA pool is preferred if available. > > Note that since coherent allocation needs remapping, one must set up > another device coherent pool by shared-dma-pool and use > dma_alloc_from_dev_coherent instead for atomic coherent allocation. > > Signed-off-by: Claire Chang <tientzu@chromium.org> > Reviewed-by: Christoph Hellwig <hch@lst.de> > --- > include/linux/swiotlb.h | 15 +++++++++++++ > kernel/dma/direct.c | 50 ++++++++++++++++++++++++++++++----------- > kernel/dma/swiotlb.c | 45 +++++++++++++++++++++++++++++++++++-- > 3 files changed, 95 insertions(+), 15 deletions(-) > > diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h > index efcd56e3a16c..2d5ec670e064 100644 > --- a/include/linux/swiotlb.h > +++ b/include/linux/swiotlb.h > @@ -156,4 +156,19 @@ static inline void swiotlb_adjust_size(unsigned long size) > extern void swiotlb_print_info(void); > extern void swiotlb_set_max_segment(unsigned int); > > +#ifdef CONFIG_DMA_RESTRICTED_POOL > +struct page *swiotlb_alloc(struct device *dev, size_t size); > +bool swiotlb_free(struct device *dev, struct page *page, size_t size); > +#else > +static inline struct page *swiotlb_alloc(struct device *dev, size_t size) > +{ > + return NULL; > +} > +static inline bool swiotlb_free(struct device *dev, struct page *page, > + size_t size) > +{ > + return false; > +} > +#endif /* CONFIG_DMA_RESTRICTED_POOL */ > + > #endif /* __LINUX_SWIOTLB_H */ > diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c > index 3713461d6fe0..da0e09621230 100644 > --- a/kernel/dma/direct.c > +++ b/kernel/dma/direct.c > @@ -75,6 +75,15 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) > min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit); > } > > +static void __dma_direct_free_pages(struct device *dev, struct page *page, > + size_t size) > +{ > + if (IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL) && > + swiotlb_free(dev, page, size)) > + return; > + dma_free_contiguous(dev, page, size); > +} > + > static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, > gfp_t gfp) > { > @@ -86,7 +95,16 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, > > gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, > &phys_limit); > - page = dma_alloc_contiguous(dev, size, gfp); > + if (IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL)) { > + page = swiotlb_alloc(dev, size); > + if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { > + __dma_direct_free_pages(dev, page, size); > + return NULL; > + } > + } > + > + if (!page) > + page = dma_alloc_contiguous(dev, size, gfp); > if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { > dma_free_contiguous(dev, page, size); > page = NULL; > @@ -142,7 +160,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, > gfp |= __GFP_NOWARN; > > if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && > - !force_dma_unencrypted(dev)) { > + !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) { > page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO); > if (!page) > return NULL; > @@ -155,18 +173,23 @@ void *dma_direct_alloc(struct device *dev, size_t size, > } > > if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && > - !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && > - !dev_is_dma_coherent(dev)) > + !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) && > + !is_dev_swiotlb_force(dev)) > return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); Just noticed that after propagating swiotlb_force setting into io_tlb_default_mem->force, the memory allocation behavior for swiotlb_force will change (i.e. always skipping arch_dma_alloc and dma_direct_alloc_from_pool). > > /* > * Remapping or decrypting memory may block. If either is required and > * we can't block, allocate the memory from the atomic pools. > + * If restricted DMA (i.e., is_dev_swiotlb_force) is required, one must > + * set up another device coherent pool by shared-dma-pool and use > + * dma_alloc_from_dev_coherent instead. > */ > if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && > !gfpflags_allow_blocking(gfp) && > (force_dma_unencrypted(dev) || > - (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev)))) > + (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && > + !dev_is_dma_coherent(dev))) && > + !is_dev_swiotlb_force(dev)) > return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); And here. > > /* we always manually zero the memory once we are done */ > @@ -237,7 +260,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, > return NULL; > } > out_free_pages: > - dma_free_contiguous(dev, page, size); > + __dma_direct_free_pages(dev, page, size); > return NULL; > } > > @@ -247,15 +270,15 @@ void dma_direct_free(struct device *dev, size_t size, > unsigned int page_order = get_order(size); > > if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && > - !force_dma_unencrypted(dev)) { > + !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) { > /* cpu_addr is a struct page cookie, not a kernel address */ > dma_free_contiguous(dev, cpu_addr, size); > return; > } > > if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && > - !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && > - !dev_is_dma_coherent(dev)) { > + !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) && > + !is_dev_swiotlb_force(dev)) { > arch_dma_free(dev, size, cpu_addr, dma_addr, attrs); > return; > } > @@ -273,7 +296,7 @@ void dma_direct_free(struct device *dev, size_t size, > else if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) > arch_dma_clear_uncached(cpu_addr, size); > > - dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size); > + __dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size); > } > > struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > @@ -283,7 +306,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > void *ret; > > if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && > - force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp)) > + force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) && > + !is_dev_swiotlb_force(dev)) > return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); > > page = __dma_direct_alloc_pages(dev, size, gfp); > @@ -310,7 +334,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, > *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); > return page; > out_free_pages: > - dma_free_contiguous(dev, page, size); > + __dma_direct_free_pages(dev, page, size); > return NULL; > } > > @@ -329,7 +353,7 @@ void dma_direct_free_pages(struct device *dev, size_t size, > if (force_dma_unencrypted(dev)) > set_memory_encrypted((unsigned long)vaddr, 1 << page_order); > > - dma_free_contiguous(dev, page, size); > + __dma_direct_free_pages(dev, page, size); > } > > #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ > diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c > index fec4934b9926..6ad85b48f101 100644 > --- a/kernel/dma/swiotlb.c > +++ b/kernel/dma/swiotlb.c > @@ -462,8 +462,9 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, > > index = wrap = wrap_index(mem, ALIGN(mem->index, stride)); > do { > - if ((slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != > - (orig_addr & iotlb_align_mask)) { > + if (orig_addr && > + (slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != > + (orig_addr & iotlb_align_mask)) { > index = wrap_index(mem, index + 1); > continue; > } > @@ -702,3 +703,43 @@ static int __init swiotlb_create_default_debugfs(void) > late_initcall(swiotlb_create_default_debugfs); > > #endif > + > +#ifdef CONFIG_DMA_RESTRICTED_POOL > +struct page *swiotlb_alloc(struct device *dev, size_t size) > +{ > + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; > + phys_addr_t tlb_addr; > + int index; > + > + /* > + * Skip io_tlb_default_mem since swiotlb_alloc doesn't support atomic > + * coherent allocation. Otherwise might break existing devices. > + * One must set up another device coherent pool by shared-dma-pool and > + * use dma_alloc_from_dev_coherent instead for atomic coherent > + * allocation to avoid memory remapping. > + */ > + if (!mem || mem == io_tlb_default_mem) > + return NULL; > + > + index = swiotlb_find_slots(dev, 0, size); > + if (index == -1) > + return NULL; > + > + tlb_addr = slot_addr(mem->start, index); > + > + return pfn_to_page(PFN_DOWN(tlb_addr)); > +} > + > +bool swiotlb_free(struct device *dev, struct page *page, size_t size) > +{ > + phys_addr_t tlb_addr = page_to_phys(page); > + > + if (!is_swiotlb_buffer(dev, tlb_addr)) > + return false; > + > + swiotlb_release_slots(dev, tlb_addr); > + > + return true; > +} > + > +#endif /* CONFIG_DMA_RESTRICTED_POOL */ > -- > 2.32.0.272.g935e593368-goog >
On Wed, Jun 16, 2021 at 12:04:16PM +0800, Claire Chang wrote: > Just noticed that after propagating swiotlb_force setting into > io_tlb_default_mem->force, the memory allocation behavior for > swiotlb_force will change (i.e. always skipping arch_dma_alloc and > dma_direct_alloc_from_pool). Yes, I think we need to split a "use_for_alloc" flag from the force flag.
On Wed, Jun 16, 2021 at 12:59 PM Christoph Hellwig <hch@lst.de> wrote: > > On Wed, Jun 16, 2021 at 12:04:16PM +0800, Claire Chang wrote: > > Just noticed that after propagating swiotlb_force setting into > > io_tlb_default_mem->force, the memory allocation behavior for > > swiotlb_force will change (i.e. always skipping arch_dma_alloc and > > dma_direct_alloc_from_pool). > > Yes, I think we need to split a "use_for_alloc" flag from the force flag. How about splitting is_dev_swiotlb_force into is_swiotlb_force_bounce (io_tlb_mem->force_bounce) and is_swiotlb_force_alloc (io_tlb_mem->force_alloc)?
On Wed, Jun 16, 2021 at 01:10:02PM +0800, Claire Chang wrote: > On Wed, Jun 16, 2021 at 12:59 PM Christoph Hellwig <hch@lst.de> wrote: > > > > On Wed, Jun 16, 2021 at 12:04:16PM +0800, Claire Chang wrote: > > > Just noticed that after propagating swiotlb_force setting into > > > io_tlb_default_mem->force, the memory allocation behavior for > > > swiotlb_force will change (i.e. always skipping arch_dma_alloc and > > > dma_direct_alloc_from_pool). > > > > Yes, I think we need to split a "use_for_alloc" flag from the force flag. > > How about splitting is_dev_swiotlb_force into is_swiotlb_force_bounce > (io_tlb_mem->force_bounce) and is_swiotlb_force_alloc > (io_tlb_mem->force_alloc)? Yes, something like that. I'd probably not use force for the alloc side given that we otherwise never allocte from the swiotlb buffer.
diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index efcd56e3a16c..2d5ec670e064 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -156,4 +156,19 @@ static inline void swiotlb_adjust_size(unsigned long size) extern void swiotlb_print_info(void); extern void swiotlb_set_max_segment(unsigned int); +#ifdef CONFIG_DMA_RESTRICTED_POOL +struct page *swiotlb_alloc(struct device *dev, size_t size); +bool swiotlb_free(struct device *dev, struct page *page, size_t size); +#else +static inline struct page *swiotlb_alloc(struct device *dev, size_t size) +{ + return NULL; +} +static inline bool swiotlb_free(struct device *dev, struct page *page, + size_t size) +{ + return false; +} +#endif /* CONFIG_DMA_RESTRICTED_POOL */ + #endif /* __LINUX_SWIOTLB_H */ diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 3713461d6fe0..da0e09621230 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -75,6 +75,15 @@ static bool dma_coherent_ok(struct device *dev, phys_addr_t phys, size_t size) min_not_zero(dev->coherent_dma_mask, dev->bus_dma_limit); } +static void __dma_direct_free_pages(struct device *dev, struct page *page, + size_t size) +{ + if (IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL) && + swiotlb_free(dev, page, size)) + return; + dma_free_contiguous(dev, page, size); +} + static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, gfp_t gfp) { @@ -86,7 +95,16 @@ static struct page *__dma_direct_alloc_pages(struct device *dev, size_t size, gfp |= dma_direct_optimal_gfp_mask(dev, dev->coherent_dma_mask, &phys_limit); - page = dma_alloc_contiguous(dev, size, gfp); + if (IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL)) { + page = swiotlb_alloc(dev, size); + if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { + __dma_direct_free_pages(dev, page, size); + return NULL; + } + } + + if (!page) + page = dma_alloc_contiguous(dev, size, gfp); if (page && !dma_coherent_ok(dev, page_to_phys(page), size)) { dma_free_contiguous(dev, page, size); page = NULL; @@ -142,7 +160,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, gfp |= __GFP_NOWARN; if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && - !force_dma_unencrypted(dev)) { + !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) { page = __dma_direct_alloc_pages(dev, size, gfp & ~__GFP_ZERO); if (!page) return NULL; @@ -155,18 +173,23 @@ void *dma_direct_alloc(struct device *dev, size_t size, } if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && - !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && - !dev_is_dma_coherent(dev)) + !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) && + !is_dev_swiotlb_force(dev)) return arch_dma_alloc(dev, size, dma_handle, gfp, attrs); /* * Remapping or decrypting memory may block. If either is required and * we can't block, allocate the memory from the atomic pools. + * If restricted DMA (i.e., is_dev_swiotlb_force) is required, one must + * set up another device coherent pool by shared-dma-pool and use + * dma_alloc_from_dev_coherent instead. */ if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && !gfpflags_allow_blocking(gfp) && (force_dma_unencrypted(dev) || - (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev)))) + (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && + !dev_is_dma_coherent(dev))) && + !is_dev_swiotlb_force(dev)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); /* we always manually zero the memory once we are done */ @@ -237,7 +260,7 @@ void *dma_direct_alloc(struct device *dev, size_t size, return NULL; } out_free_pages: - dma_free_contiguous(dev, page, size); + __dma_direct_free_pages(dev, page, size); return NULL; } @@ -247,15 +270,15 @@ void dma_direct_free(struct device *dev, size_t size, unsigned int page_order = get_order(size); if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && - !force_dma_unencrypted(dev)) { + !force_dma_unencrypted(dev) && !is_dev_swiotlb_force(dev)) { /* cpu_addr is a struct page cookie, not a kernel address */ dma_free_contiguous(dev, cpu_addr, size); return; } if (!IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED) && - !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && - !dev_is_dma_coherent(dev)) { + !IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && !dev_is_dma_coherent(dev) && + !is_dev_swiotlb_force(dev)) { arch_dma_free(dev, size, cpu_addr, dma_addr, attrs); return; } @@ -273,7 +296,7 @@ void dma_direct_free(struct device *dev, size_t size, else if (IS_ENABLED(CONFIG_ARCH_HAS_DMA_CLEAR_UNCACHED)) arch_dma_clear_uncached(cpu_addr, size); - dma_free_contiguous(dev, dma_direct_to_page(dev, dma_addr), size); + __dma_direct_free_pages(dev, dma_direct_to_page(dev, dma_addr), size); } struct page *dma_direct_alloc_pages(struct device *dev, size_t size, @@ -283,7 +306,8 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, void *ret; if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && - force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp)) + force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp) && + !is_dev_swiotlb_force(dev)) return dma_direct_alloc_from_pool(dev, size, dma_handle, gfp); page = __dma_direct_alloc_pages(dev, size, gfp); @@ -310,7 +334,7 @@ struct page *dma_direct_alloc_pages(struct device *dev, size_t size, *dma_handle = phys_to_dma_direct(dev, page_to_phys(page)); return page; out_free_pages: - dma_free_contiguous(dev, page, size); + __dma_direct_free_pages(dev, page, size); return NULL; } @@ -329,7 +353,7 @@ void dma_direct_free_pages(struct device *dev, size_t size, if (force_dma_unencrypted(dev)) set_memory_encrypted((unsigned long)vaddr, 1 << page_order); - dma_free_contiguous(dev, page, size); + __dma_direct_free_pages(dev, page, size); } #if defined(CONFIG_ARCH_HAS_SYNC_DMA_FOR_DEVICE) || \ diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index fec4934b9926..6ad85b48f101 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -462,8 +462,9 @@ static int swiotlb_find_slots(struct device *dev, phys_addr_t orig_addr, index = wrap = wrap_index(mem, ALIGN(mem->index, stride)); do { - if ((slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != - (orig_addr & iotlb_align_mask)) { + if (orig_addr && + (slot_addr(tbl_dma_addr, index) & iotlb_align_mask) != + (orig_addr & iotlb_align_mask)) { index = wrap_index(mem, index + 1); continue; } @@ -702,3 +703,43 @@ static int __init swiotlb_create_default_debugfs(void) late_initcall(swiotlb_create_default_debugfs); #endif + +#ifdef CONFIG_DMA_RESTRICTED_POOL +struct page *swiotlb_alloc(struct device *dev, size_t size) +{ + struct io_tlb_mem *mem = dev->dma_io_tlb_mem; + phys_addr_t tlb_addr; + int index; + + /* + * Skip io_tlb_default_mem since swiotlb_alloc doesn't support atomic + * coherent allocation. Otherwise might break existing devices. + * One must set up another device coherent pool by shared-dma-pool and + * use dma_alloc_from_dev_coherent instead for atomic coherent + * allocation to avoid memory remapping. + */ + if (!mem || mem == io_tlb_default_mem) + return NULL; + + index = swiotlb_find_slots(dev, 0, size); + if (index == -1) + return NULL; + + tlb_addr = slot_addr(mem->start, index); + + return pfn_to_page(PFN_DOWN(tlb_addr)); +} + +bool swiotlb_free(struct device *dev, struct page *page, size_t size) +{ + phys_addr_t tlb_addr = page_to_phys(page); + + if (!is_swiotlb_buffer(dev, tlb_addr)) + return false; + + swiotlb_release_slots(dev, tlb_addr); + + return true; +} + +#endif /* CONFIG_DMA_RESTRICTED_POOL */
Add the functions, swiotlb_{alloc,free} to support the memory allocation from restricted DMA pool. The restricted DMA pool is preferred if available. Note that since coherent allocation needs remapping, one must set up another device coherent pool by shared-dma-pool and use dma_alloc_from_dev_coherent instead for atomic coherent allocation. Signed-off-by: Claire Chang <tientzu@chromium.org> Reviewed-by: Christoph Hellwig <hch@lst.de> --- include/linux/swiotlb.h | 15 +++++++++++++ kernel/dma/direct.c | 50 ++++++++++++++++++++++++++++++----------- kernel/dma/swiotlb.c | 45 +++++++++++++++++++++++++++++++++++-- 3 files changed, 95 insertions(+), 15 deletions(-)