1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Memory Encryption Support Common Code 4 * 5 * Copyright (C) 2016 Advanced Micro Devices, Inc. 6 * 7 * Author: Tom Lendacky <thomas.lendacky@amd.com> 8 */ 9 10 #include <linux/dma-direct.h> 11 #include <linux/dma-mapping.h> 12 #include <linux/swiotlb.h> 13 #include <linux/cc_platform.h> 14 #include <linux/mem_encrypt.h> 15 16 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ 17 bool force_dma_unencrypted(struct device *dev) 18 { 19 /* 20 * For SEV, all DMA must be to unencrypted addresses. 21 */ 22 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) 23 return true; 24 25 /* 26 * For SME, all DMA must be to unencrypted addresses if the 27 * device does not support DMA to addresses that include the 28 * encryption mask. 29 */ 30 if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { 31 u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask)); 32 u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask, 33 dev->bus_dma_limit); 34 35 if (dma_dev_mask <= dma_enc_mask) 36 return true; 37 } 38 39 return false; 40 } 41 42 static void print_mem_encrypt_feature_info(void) 43 { 44 pr_info("Memory Encryption Features active:"); 45 46 if (cpu_feature_enabled(X86_FEATURE_TDX_GUEST)) { 47 pr_cont(" Intel TDX\n"); 48 return; 49 } 50 51 pr_cont(" AMD"); 52 53 /* Secure Memory Encryption */ 54 if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { 55 /* 56 * SME is mutually exclusive with any of the SEV 57 * features below. 58 */ 59 pr_cont(" SME\n"); 60 return; 61 } 62 63 /* Secure Encrypted Virtualization */ 64 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) 65 pr_cont(" SEV"); 66 67 /* Encrypted Register State */ 68 if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) 69 pr_cont(" SEV-ES"); 70 71 /* Secure Nested Paging */ 72 if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) 73 pr_cont(" SEV-SNP"); 74 75 pr_cont("\n"); 76 } 77 78 /* Architecture __weak replacement functions */ 79 void __init mem_encrypt_init(void) 80 { 81 if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT)) 82 return; 83 84 /* Call into SWIOTLB to update the SWIOTLB DMA buffers */ 85 swiotlb_update_mem_attributes(); 86 87 print_mem_encrypt_feature_info(); 88 } 89