swiotlb_alloc_tlb() can allocate from the DMA atomic pool when a decrypted pool is needed from atomic context. With CONFIG_DMA_DIRECT_REMAP, the atomic pool is backed by remapped virtual addresses, which are not the same as the direct-map addresses returned by phys_to_virt().
swiotlb_init_io_tlb_pool() currently reconstructs the pool virtual address from the physical start address. For atomic-pool backed allocations this stores the wrong address in pool->vaddr. Later, swiotlb_free_tlb() passes that address to dma_free_from_pool(), which will fail to recognize the chunk Pass the virtual address returned by the allocation path into swiotlb_init_io_tlb_pool(), and store that address in pool->vaddr. This keeps the pool free path using the same virtual address as the allocator. Signed-off-by: Aneesh Kumar K.V (Arm) <[email protected]> --- kernel/dma/swiotlb.c | 32 +++++++++++++++++++------------- 1 file changed, 19 insertions(+), 13 deletions(-) diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c index 14d834ca298b..e4bd8c9eaeda 100644 --- a/kernel/dma/swiotlb.c +++ b/kernel/dma/swiotlb.c @@ -302,9 +302,9 @@ void __init swiotlb_update_mem_attributes(void) } static void swiotlb_init_io_tlb_pool(struct io_tlb_pool *mem, phys_addr_t start, - unsigned long nslabs, bool late_alloc, unsigned int nareas) + void *vaddr, unsigned long nslabs, bool late_alloc, + unsigned int nareas) { - void *vaddr = phys_to_virt(start); unsigned long bytes = nslabs << IO_TLB_SHIFT, i; mem->nslabs = nslabs; @@ -445,7 +445,7 @@ void __init swiotlb_init_remap(bool addressing_limit, unsigned int flags, return; } - swiotlb_init_io_tlb_pool(mem, __pa(tlb), nslabs, false, nareas); + swiotlb_init_io_tlb_pool(mem, __pa(tlb), tlb, nslabs, false, nareas); add_mem_pool(&io_tlb_default_mem, mem); if (flags & SWIOTLB_VERBOSE) @@ -553,7 +553,7 @@ int swiotlb_init_late(size_t size, gfp_t gfp_mask, } } - swiotlb_init_io_tlb_pool(mem, virt_to_phys(vstart), nslabs, true, + swiotlb_init_io_tlb_pool(mem, virt_to_phys(vstart), vstart, nslabs, true, nareas); add_mem_pool(&io_tlb_default_mem, mem); @@ -664,25 +664,26 @@ static struct page *alloc_dma_pages(gfp_t gfp, size_t bytes, * @phys_limit: Maximum allowed physical address of the buffer. * @attrs: DMA attributes for the allocation. * @gfp: GFP flags for the allocation. + * @vaddr: Receives the virtual address for the allocated buffer. * * Return: Allocated pages, or %NULL on allocation failure. */ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, - u64 phys_limit, unsigned long attrs, gfp_t gfp) + u64 phys_limit, unsigned long attrs, gfp_t gfp, void **vaddr) { struct page *page; + *vaddr = NULL; + /* * Allocate from the atomic pools if memory is encrypted and * the allocation is atomic, because decrypting may block. */ if (!gfpflags_allow_blocking(gfp) && (attrs & DMA_ATTR_CC_SHARED)) { - void *vaddr; - if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL)) return NULL; - return dma_alloc_from_pool(dev, bytes, &vaddr, gfp, + return dma_alloc_from_pool(dev, bytes, vaddr, gfp, attrs, dma_coherent_ok); } @@ -705,6 +706,8 @@ static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes, return NULL; } + if (page) + *vaddr = phys_to_virt(page_to_phys(page)); return page; } @@ -750,6 +753,7 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev, { struct io_tlb_pool *pool; unsigned int slot_order; + void *tlb_vaddr; struct page *tlb; size_t pool_size; size_t tlb_size; @@ -767,7 +771,8 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev, pool->unencrypted = !!(attrs & DMA_ATTR_CC_SHARED); tlb_size = nslabs << IO_TLB_SHIFT; - while (!(tlb = swiotlb_alloc_tlb(dev, tlb_size, phys_limit, attrs, gfp))) { + while (!(tlb = swiotlb_alloc_tlb(dev, tlb_size, phys_limit, attrs, gfp, + &tlb_vaddr))) { if (nslabs <= minslabs) goto error_tlb; nslabs = ALIGN(nslabs >> 1, IO_TLB_SEGSIZE); @@ -781,12 +786,12 @@ static struct io_tlb_pool *swiotlb_alloc_pool(struct device *dev, if (!pool->slots) goto error_slots; - swiotlb_init_io_tlb_pool(pool, page_to_phys(tlb), nslabs, true, nareas); + swiotlb_init_io_tlb_pool(pool, page_to_phys(tlb), tlb_vaddr, nslabs, + true, nareas); return pool; error_slots: - swiotlb_free_tlb(page_address(tlb), tlb_size, - !!(attrs & DMA_ATTR_CC_SHARED)); + swiotlb_free_tlb(tlb_vaddr, tlb_size, !!(attrs & DMA_ATTR_CC_SHARED)); error_tlb: kfree(pool); error: @@ -1995,7 +2000,8 @@ static int rmem_swiotlb_device_init(struct reserved_mem *rmem, mem->unencrypted = false; } - swiotlb_init_io_tlb_pool(pool, rmem->base, nslabs, + swiotlb_init_io_tlb_pool(pool, rmem->base, phys_to_virt(rmem->base), + nslabs, false, nareas); mem->force_bounce = true; mem->for_alloc = true; -- 2.43.0
