From 20f07a044a76aebaaa0603038857229b5c460d69 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Mon, 6 Dec 2021 16:55:05 +0300 Subject: [PATCH] x86/sev: Move common memory encryption code to mem_encrypt.c SEV and TDX both protect guest memory from host accesses. They both use guest physical address bits to communicate to the hardware which pages receive protection or not. SEV and TDX both assume that all I/O (real devices and virtio) must be performed to pages *without* protection. To add this support, AMD SEV code forces force_dma_unencrypted() to decrypt DMA pages when DMA pages were allocated for I/O. It also uses swiotlb_update_mem_attributes() to update decryption bits in SWIOTLB DMA buffers. Since TDX also uses a similar memory sharing design, all the above mentioned changes can be reused. So move force_dma_unencrypted(), SWIOTLB update code and virtio changes out of mem_encrypt_amd.c to mem_encrypt.c. Introduce a new config option X86_MEM_ENCRYPT that can be selected by platforms which use x86 memory encryption features (needed in both AMD SEV and Intel TDX guest platforms). Since the code is moved from mem_encrypt_amd.c, inherit the same make flags. This is preparation for enabling TDX memory encryption support and it has no functional changes. Co-developed-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kuppuswamy Sathyanarayanan Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov Reviewed-by: Andi Kleen Reviewed-by: Tony Luck Reviewed-by: Tom Lendacky Tested-by: Tom Lendacky Link: https://lore.kernel.org/r/20211206135505.75045-4-kirill.shutemov@linux.intel.com --- arch/x86/Kconfig | 10 ++++-- arch/x86/mm/Makefile | 5 +++ arch/x86/mm/mem_encrypt.c | 84 +++++++++++++++++++++++++++++++++++++++++++ arch/x86/mm/mem_encrypt_amd.c | 69 ----------------------------------- 4 files changed, 96 insertions(+), 72 deletions(-) create mode 100644 arch/x86/mm/mem_encrypt.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 95dd1ee..793e9b4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1523,16 +1523,20 @@ config X86_CPA_STATISTICS helps to determine the effectiveness of preserving large and huge page mappings when mapping protections are changed. +config X86_MEM_ENCRYPT + select ARCH_HAS_FORCE_DMA_UNENCRYPTED + select DYNAMIC_PHYSICAL_MASK + select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS + def_bool n + config AMD_MEM_ENCRYPT bool "AMD Secure Memory Encryption (SME) support" depends on X86_64 && CPU_SUP_AMD select DMA_COHERENT_POOL - select DYNAMIC_PHYSICAL_MASK select ARCH_USE_MEMREMAP_PROT - select ARCH_HAS_FORCE_DMA_UNENCRYPTED select INSTRUCTION_DECODER - select ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS select ARCH_HAS_CC_PLATFORM + select X86_MEM_ENCRYPT help Say yes to enable support for the encryption of system memory. This requires an AMD processor that supports Secure Memory diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index c9c4806..fe3d306 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -1,9 +1,11 @@ # SPDX-License-Identifier: GPL-2.0 # Kernel does not boot with instrumentation of tlb.c and mem_encrypt*.c KCOV_INSTRUMENT_tlb.o := n +KCOV_INSTRUMENT_mem_encrypt.o := n KCOV_INSTRUMENT_mem_encrypt_amd.o := n KCOV_INSTRUMENT_mem_encrypt_identity.o := n +KASAN_SANITIZE_mem_encrypt.o := n KASAN_SANITIZE_mem_encrypt_amd.o := n KASAN_SANITIZE_mem_encrypt_identity.o := n @@ -12,6 +14,7 @@ KASAN_SANITIZE_mem_encrypt_identity.o := n KCSAN_SANITIZE := n ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_mem_encrypt.o = -pg CFLAGS_REMOVE_mem_encrypt_amd.o = -pg CFLAGS_REMOVE_mem_encrypt_identity.o = -pg endif @@ -52,6 +55,8 @@ obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o obj-$(CONFIG_PAGE_TABLE_ISOLATION) += pti.o +obj-$(CONFIG_X86_MEM_ENCRYPT) += mem_encrypt.o obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_amd.o + obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_identity.o obj-$(CONFIG_AMD_MEM_ENCRYPT) += mem_encrypt_boot.o diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c new file mode 100644 index 0000000..50d2099 --- /dev/null +++ b/arch/x86/mm/mem_encrypt.c @@ -0,0 +1,84 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Memory Encryption Support Common Code + * + * Copyright (C) 2016 Advanced Micro Devices, Inc. + * + * Author: Tom Lendacky + */ + +#include +#include +#include +#include +#include +#include + +/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ +bool force_dma_unencrypted(struct device *dev) +{ + /* + * For SEV, all DMA must be to unencrypted addresses. + */ + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + return true; + + /* + * For SME, all DMA must be to unencrypted addresses if the + * device does not support DMA to addresses that include the + * encryption mask. + */ + if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { + u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask)); + u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask, + dev->bus_dma_limit); + + if (dma_dev_mask <= dma_enc_mask) + return true; + } + + return false; +} + +static void print_mem_encrypt_feature_info(void) +{ + pr_info("AMD Memory Encryption Features active:"); + + /* Secure Memory Encryption */ + if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { + /* + * SME is mutually exclusive with any of the SEV + * features below. + */ + pr_cont(" SME\n"); + return; + } + + /* Secure Encrypted Virtualization */ + if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) + pr_cont(" SEV"); + + /* Encrypted Register State */ + if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) + pr_cont(" SEV-ES"); + + pr_cont("\n"); +} + +/* Architecture __weak replacement functions */ +void __init mem_encrypt_init(void) +{ + if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT)) + return; + + /* Call into SWIOTLB to update the SWIOTLB DMA buffers */ + swiotlb_update_mem_attributes(); + + print_mem_encrypt_feature_info(); +} + +int arch_has_restricted_virtio_memory_access(void) +{ + return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT); +} +EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access); diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c index b520021..2b2d018 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -413,32 +413,6 @@ void __init early_set_mem_enc_dec_hypercall(unsigned long vaddr, int npages, boo notify_range_enc_status_changed(vaddr, npages, enc); } -/* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ -bool force_dma_unencrypted(struct device *dev) -{ - /* - * For SEV, all DMA must be to unencrypted addresses. - */ - if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) - return true; - - /* - * For SME, all DMA must be to unencrypted addresses if the - * device does not support DMA to addresses that include the - * encryption mask. - */ - if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { - u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask)); - u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask, - dev->bus_dma_limit); - - if (dma_dev_mask <= dma_enc_mask) - return true; - } - - return false; -} - void __init mem_encrypt_free_decrypted_mem(void) { unsigned long vaddr, vaddr_end, npages; @@ -462,46 +436,3 @@ void __init mem_encrypt_free_decrypted_mem(void) free_init_pages("unused decrypted", vaddr, vaddr_end); } - -static void print_mem_encrypt_feature_info(void) -{ - pr_info("AMD Memory Encryption Features active:"); - - /* Secure Memory Encryption */ - if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { - /* - * SME is mutually exclusive with any of the SEV - * features below. - */ - pr_cont(" SME\n"); - return; - } - - /* Secure Encrypted Virtualization */ - if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) - pr_cont(" SEV"); - - /* Encrypted Register State */ - if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) - pr_cont(" SEV-ES"); - - pr_cont("\n"); -} - -/* 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(); - - print_mem_encrypt_feature_info(); -} - -int arch_has_restricted_virtio_memory_access(void) -{ - return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT); -} -EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access); -- 2.7.4