From c7753208a94c73d5beb1e4bd843081d6dc7d4678 Mon Sep 17 00:00:00 2001 From: Tom Lendacky Date: Mon, 17 Jul 2017 16:10:21 -0500 Subject: [PATCH] x86, swiotlb: Add memory encryption support MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Since DMA addresses will effectively look like 48-bit addresses when the memory encryption mask is set, SWIOTLB is needed if the DMA mask of the device performing the DMA does not support 48-bits. SWIOTLB will be initialized to create decrypted bounce buffers for use by these devices. Signed-off-by: Tom Lendacky Reviewed-by: Thomas Gleixner Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Brijesh Singh Cc: Dave Young Cc: Dmitry Vyukov Cc: Jonathan Corbet Cc: Konrad Rzeszutek Wilk Cc: Larry Woodman Cc: Linus Torvalds Cc: Matt Fleming Cc: Michael S. Tsirkin Cc: Paolo Bonzini Cc: Peter Zijlstra Cc: Radim Krčmář Cc: Rik van Riel Cc: Toshimitsu Kani Cc: kasan-dev@googlegroups.com Cc: kvm@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-efi@vger.kernel.org Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/aa2d29b78ae7d508db8881e46a3215231b9327a7.1500319216.git.thomas.lendacky@amd.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/dma-mapping.h | 5 +-- arch/x86/include/asm/mem_encrypt.h | 5 +++ arch/x86/kernel/pci-dma.c | 11 +++--- arch/x86/kernel/pci-nommu.c | 2 +- arch/x86/kernel/pci-swiotlb.c | 15 +++++++-- arch/x86/mm/mem_encrypt.c | 22 ++++++++++++ include/linux/swiotlb.h | 1 + init/main.c | 10 ++++++ lib/swiotlb.c | 54 +++++++++++++++++++++++++----- 9 files changed, 108 insertions(+), 17 deletions(-) diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h index 398c79889f5c..1387dafdba2d 100644 --- a/arch/x86/include/asm/dma-mapping.h +++ b/arch/x86/include/asm/dma-mapping.h @@ -12,6 +12,7 @@ #include #include #include +#include #ifdef CONFIG_ISA # define ISA_DMA_BIT_MASK DMA_BIT_MASK(24) @@ -57,12 +58,12 @@ static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size) static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr) { - return paddr; + return __sme_set(paddr); } static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr) { - return daddr; + return __sme_clr(daddr); } #endif /* CONFIG_X86_DMA_REMAP */ diff --git a/arch/x86/include/asm/mem_encrypt.h b/arch/x86/include/asm/mem_encrypt.h index ab1fe77c2f73..70e55f6b9adf 100644 --- a/arch/x86/include/asm/mem_encrypt.h +++ b/arch/x86/include/asm/mem_encrypt.h @@ -34,6 +34,11 @@ void __init sme_early_init(void); void __init sme_encrypt_kernel(void); void __init sme_enable(void); +/* Architecture __weak replacement functions */ +void __init mem_encrypt_init(void); + +void swiotlb_set_mem_attributes(void *vaddr, unsigned long size); + #else /* !CONFIG_AMD_MEM_ENCRYPT */ #define sme_me_mask 0UL diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 5e16d3f29594..0accc2404b92 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -93,9 +93,12 @@ again: if (gfpflags_allow_blocking(flag)) { page = dma_alloc_from_contiguous(dev, count, get_order(size), flag); - if (page && page_to_phys(page) + size > dma_mask) { - dma_release_from_contiguous(dev, page, count); - page = NULL; + if (page) { + addr = phys_to_dma(dev, page_to_phys(page)); + if (addr + size > dma_mask) { + dma_release_from_contiguous(dev, page, count); + page = NULL; + } } } /* fallback */ @@ -104,7 +107,7 @@ again: if (!page) return NULL; - addr = page_to_phys(page); + addr = phys_to_dma(dev, page_to_phys(page)); if (addr + size > dma_mask) { __free_pages(page, get_order(size)); diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c index a6d404087fe3..4fc3cb60ea11 100644 --- a/arch/x86/kernel/pci-nommu.c +++ b/arch/x86/kernel/pci-nommu.c @@ -32,7 +32,7 @@ static dma_addr_t nommu_map_page(struct device *dev, struct page *page, enum dma_data_direction dir, unsigned long attrs) { - dma_addr_t bus = page_to_phys(page) + offset; + dma_addr_t bus = phys_to_dma(dev, page_to_phys(page)) + offset; WARN_ON(size == 0); if (!check_addr("map_single", dev, bus, size)) return NOMMU_MAPPING_ERROR; diff --git a/arch/x86/kernel/pci-swiotlb.c b/arch/x86/kernel/pci-swiotlb.c index 1e23577e17cf..677077510e30 100644 --- a/arch/x86/kernel/pci-swiotlb.c +++ b/arch/x86/kernel/pci-swiotlb.c @@ -6,12 +6,14 @@ #include #include #include +#include #include #include #include #include #include + int swiotlb __read_mostly; void *x86_swiotlb_alloc_coherent(struct device *hwdev, size_t size, @@ -79,8 +81,8 @@ IOMMU_INIT_FINISH(pci_swiotlb_detect_override, pci_swiotlb_late_init); /* - * if 4GB or more detected (and iommu=off not set) return 1 - * and set swiotlb to 1. + * If 4GB or more detected (and iommu=off not set) or if SME is active + * then set swiotlb to 1 and return 1. */ int __init pci_swiotlb_detect_4gb(void) { @@ -89,6 +91,15 @@ int __init pci_swiotlb_detect_4gb(void) if (!no_iommu && max_possible_pfn > MAX_DMA32_PFN) swiotlb = 1; #endif + + /* + * If SME is active then swiotlb will be set to 1 so that bounce + * buffers are allocated and used for devices that do not support + * the addressing range required for the encryption mask. + */ + if (sme_active()) + swiotlb = 1; + return swiotlb; } IOMMU_INIT(pci_swiotlb_detect_4gb, diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c index 0843d023da4a..a7400ec8538b 100644 --- a/arch/x86/mm/mem_encrypt.c +++ b/arch/x86/mm/mem_encrypt.c @@ -13,11 +13,14 @@ #include #include #include +#include +#include #include #include #include #include +#include /* * Since SME related variables are set early in the boot process they must @@ -177,6 +180,25 @@ void __init sme_early_init(void) protection_map[i] = pgprot_encrypted(protection_map[i]); } +/* Architecture __weak replacement functions */ +void __init mem_encrypt_init(void) +{ + if (!sme_me_mask) + return; + + /* Call into SWIOTLB to update the SWIOTLB DMA buffers */ + swiotlb_update_mem_attributes(); +} + +void swiotlb_set_mem_attributes(void *vaddr, unsigned long size) +{ + WARN(PAGE_ALIGN(size) != size, + "size is not page-aligned (%#lx)\n", size); + + /* Make the SWIOTLB buffer area decrypted */ + set_memory_decrypted((unsigned long)vaddr, size >> PAGE_SHIFT); +} + void __init sme_encrypt_kernel(void) { } diff --git a/include/linux/swiotlb.h b/include/linux/swiotlb.h index 4ee479f2f355..15e7160751a8 100644 --- a/include/linux/swiotlb.h +++ b/include/linux/swiotlb.h @@ -35,6 +35,7 @@ int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose); extern unsigned long swiotlb_nr_tbl(void); unsigned long swiotlb_size_or_default(void); extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs); +extern void __init swiotlb_update_mem_attributes(void); /* * Enumeration for sync targets diff --git a/init/main.c b/init/main.c index 052481fbe363..9789ab7fe85e 100644 --- a/init/main.c +++ b/init/main.c @@ -488,6 +488,8 @@ void __init __weak thread_stack_cache_init(void) } #endif +void __init __weak mem_encrypt_init(void) { } + /* * Set up kernel memory allocators */ @@ -641,6 +643,14 @@ asmlinkage __visible void __init start_kernel(void) */ locking_selftest(); + /* + * This needs to be called before any devices perform DMA + * operations that might use the SWIOTLB bounce buffers. It will + * mark the bounce buffers as decrypted so that their usage will + * not cause "plain-text" data to be decrypted when accessed. + */ + mem_encrypt_init(); + #ifdef CONFIG_BLK_DEV_INITRD if (initrd_start && !initrd_below_start_ok && page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) { diff --git a/lib/swiotlb.c b/lib/swiotlb.c index a8d74a733a38..04ac91acf193 100644 --- a/lib/swiotlb.c +++ b/lib/swiotlb.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -155,6 +156,15 @@ unsigned long swiotlb_size_or_default(void) return size ? size : (IO_TLB_DEFAULT_SIZE); } +void __weak swiotlb_set_mem_attributes(void *vaddr, unsigned long size) { } + +/* For swiotlb, clear memory encryption mask from dma addresses */ +static dma_addr_t swiotlb_phys_to_dma(struct device *hwdev, + phys_addr_t address) +{ + return __sme_clr(phys_to_dma(hwdev, address)); +} + /* Note that this doesn't work with highmem page */ static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev, volatile void *address) @@ -183,6 +193,31 @@ void swiotlb_print_info(void) bytes >> 20, vstart, vend - 1); } +/* + * Early SWIOTLB allocation may be too early to allow an architecture to + * perform the desired operations. This function allows the architecture to + * call SWIOTLB when the operations are possible. It needs to be called + * before the SWIOTLB memory is used. + */ +void __init swiotlb_update_mem_attributes(void) +{ + void *vaddr; + unsigned long bytes; + + if (no_iotlb_memory || late_alloc) + return; + + vaddr = phys_to_virt(io_tlb_start); + bytes = PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT); + swiotlb_set_mem_attributes(vaddr, bytes); + memset(vaddr, 0, bytes); + + vaddr = phys_to_virt(io_tlb_overflow_buffer); + bytes = PAGE_ALIGN(io_tlb_overflow); + swiotlb_set_mem_attributes(vaddr, bytes); + memset(vaddr, 0, bytes); +} + int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose) { void *v_overflow_buffer; @@ -320,6 +355,7 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) io_tlb_start = virt_to_phys(tlb); io_tlb_end = io_tlb_start + bytes; + swiotlb_set_mem_attributes(tlb, bytes); memset(tlb, 0, bytes); /* @@ -330,6 +366,8 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs) if (!v_overflow_buffer) goto cleanup2; + swiotlb_set_mem_attributes(v_overflow_buffer, io_tlb_overflow); + memset(v_overflow_buffer, 0, io_tlb_overflow); io_tlb_overflow_buffer = virt_to_phys(v_overflow_buffer); /* @@ -581,7 +619,7 @@ map_single(struct device *hwdev, phys_addr_t phys, size_t size, return SWIOTLB_MAP_ERROR; } - start_dma_addr = phys_to_dma(hwdev, io_tlb_start); + start_dma_addr = swiotlb_phys_to_dma(hwdev, io_tlb_start); return swiotlb_tbl_map_single(hwdev, start_dma_addr, phys, size, dir, attrs); } @@ -702,7 +740,7 @@ swiotlb_alloc_coherent(struct device *hwdev, size_t size, goto err_warn; ret = phys_to_virt(paddr); - dev_addr = phys_to_dma(hwdev, paddr); + dev_addr = swiotlb_phys_to_dma(hwdev, paddr); /* Confirm address can be DMA'd by device */ if (dev_addr + size - 1 > dma_mask) { @@ -812,10 +850,10 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, map = map_single(dev, phys, size, dir, attrs); if (map == SWIOTLB_MAP_ERROR) { swiotlb_full(dev, size, dir, 1); - return phys_to_dma(dev, io_tlb_overflow_buffer); + return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer); } - dev_addr = phys_to_dma(dev, map); + dev_addr = swiotlb_phys_to_dma(dev, map); /* Ensure that the address returned is DMA'ble */ if (dma_capable(dev, dev_addr, size)) @@ -824,7 +862,7 @@ dma_addr_t swiotlb_map_page(struct device *dev, struct page *page, attrs |= DMA_ATTR_SKIP_CPU_SYNC; swiotlb_tbl_unmap_single(dev, map, size, dir, attrs); - return phys_to_dma(dev, io_tlb_overflow_buffer); + return swiotlb_phys_to_dma(dev, io_tlb_overflow_buffer); } EXPORT_SYMBOL_GPL(swiotlb_map_page); @@ -958,7 +996,7 @@ swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems, sg_dma_len(sgl) = 0; return 0; } - sg->dma_address = phys_to_dma(hwdev, map); + sg->dma_address = swiotlb_phys_to_dma(hwdev, map); } else sg->dma_address = dev_addr; sg_dma_len(sg) = sg->length; @@ -1026,7 +1064,7 @@ EXPORT_SYMBOL(swiotlb_sync_sg_for_device); int swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr) { - return (dma_addr == phys_to_dma(hwdev, io_tlb_overflow_buffer)); + return (dma_addr == swiotlb_phys_to_dma(hwdev, io_tlb_overflow_buffer)); } EXPORT_SYMBOL(swiotlb_dma_mapping_error); @@ -1039,6 +1077,6 @@ EXPORT_SYMBOL(swiotlb_dma_mapping_error); int swiotlb_dma_supported(struct device *hwdev, u64 mask) { - return phys_to_dma(hwdev, io_tlb_end - 1) <= mask; + return swiotlb_phys_to_dma(hwdev, io_tlb_end - 1) <= mask; } EXPORT_SYMBOL(swiotlb_dma_supported); -- 2.20.1