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 */
17bool 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
42static 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 */
79void __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}