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 #include <linux/virtio_config.h> 16 17 /* Override for DMA direct allocation check - ARCH_HAS_FORCE_DMA_UNENCRYPTED */ 18 bool force_dma_unencrypted(struct device *dev) 19 { 20 /* 21 * For SEV, all DMA must be to unencrypted addresses. 22 */ 23 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) 24 return true; 25 26 /* 27 * For SME, all DMA must be to unencrypted addresses if the 28 * device does not support DMA to addresses that include the 29 * encryption mask. 30 */ 31 if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { 32 u64 dma_enc_mask = DMA_BIT_MASK(__ffs64(sme_me_mask)); 33 u64 dma_dev_mask = min_not_zero(dev->coherent_dma_mask, 34 dev->bus_dma_limit); 35 36 if (dma_dev_mask <= dma_enc_mask) 37 return true; 38 } 39 40 return false; 41 } 42 43 static void print_mem_encrypt_feature_info(void) 44 { 45 pr_info("AMD Memory Encryption Features active:"); 46 47 /* Secure Memory Encryption */ 48 if (cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) { 49 /* 50 * SME is mutually exclusive with any of the SEV 51 * features below. 52 */ 53 pr_cont(" SME\n"); 54 return; 55 } 56 57 /* Secure Encrypted Virtualization */ 58 if (cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)) 59 pr_cont(" SEV"); 60 61 /* Encrypted Register State */ 62 if (cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) 63 pr_cont(" SEV-ES"); 64 65 pr_cont("\n"); 66 } 67 68 /* Architecture __weak replacement functions */ 69 void __init mem_encrypt_init(void) 70 { 71 if (!cc_platform_has(CC_ATTR_MEM_ENCRYPT)) 72 return; 73 74 /* Call into SWIOTLB to update the SWIOTLB DMA buffers */ 75 swiotlb_update_mem_attributes(); 76 77 print_mem_encrypt_feature_info(); 78 } 79 80 int arch_has_restricted_virtio_memory_access(void) 81 { 82 return cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT); 83 } 84 EXPORT_SYMBOL_GPL(arch_has_restricted_virtio_memory_access); 85