When a device required unencrypted memory and the context does not allow blocking, memory must be returned from the atomic coherent pools.
This avoids the remap when CONFIG_DMA_DIRECT_REMAP is not enabled and the config only requires CONFIG_DMA_COHERENT_POOL. This will be used for CONFIG_AMD_MEM_ENCRYPT in a subsequent patch. Keep all memory in these pools unencrypted. Signed-off-by: David Rientjes <rient...@google.com> --- kernel/dma/direct.c | 16 ++++++++++++++++ kernel/dma/pool.c | 15 +++++++++++++-- 2 files changed, 29 insertions(+), 2 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 70800ca64f13..44165263c185 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -124,6 +124,18 @@ void *dma_direct_alloc_pages(struct device *dev, size_t size, struct page *page; void *ret; + /* + * Unencrypted memory must come directly from DMA atomic pools if + * blocking is not allowed. + */ + if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && + force_dma_unencrypted(dev) && !gfpflags_allow_blocking(gfp)) { + ret = dma_alloc_from_pool(dev, PAGE_ALIGN(size), &page, gfp); + if (!ret) + return NULL; + goto done; + } + if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP) && dma_alloc_need_uncached(dev, attrs) && !gfpflags_allow_blocking(gfp)) { @@ -203,6 +215,10 @@ void dma_direct_free_pages(struct device *dev, size_t size, void *cpu_addr, { unsigned int page_order = get_order(size); + if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL) && + dma_free_from_pool(dev, cpu_addr, PAGE_ALIGN(size))) + return; + if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) && !force_dma_unencrypted(dev)) { /* cpu_addr is a struct page cookie, not a kernel address */ diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index e14c5a2da734..6685ab89cfa7 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -9,6 +9,7 @@ #include <linux/dma-contiguous.h> #include <linux/init.h> #include <linux/genalloc.h> +#include <linux/set_memory.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/workqueue.h> @@ -55,12 +56,20 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, arch_dma_prep_coherent(page, pool_size); +#ifdef CONFIG_DMA_DIRECT_REMAP addr = dma_common_contiguous_remap(page, pool_size, pgprot_dmacoherent(PAGE_KERNEL), __builtin_return_address(0)); if (!addr) goto free_page; - +#else + addr = page_to_virt(page); +#endif + /* + * Memory in the atomic DMA pools must be unencrypted, the pools do not + * shrink so no re-encryption occurs in dma_direct_free_pages(). + */ + set_memory_decrypted((unsigned long)page_to_virt(page), 1 << order); ret = gen_pool_add_virt(pool, (unsigned long)addr, page_to_phys(page), pool_size, NUMA_NO_NODE); if (ret) @@ -69,8 +78,10 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, return 0; remove_mapping: +#ifdef CONFIG_DMA_DIRECT_REMAP dma_common_free_remap(addr, pool_size); -free_page: +#endif +free_page: __maybe_unused if (!dma_release_from_contiguous(NULL, page, 1 << order)) __free_pages(page, order); out: _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu