1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
From 45f7a023504c57c0820c1d816a7298bf35ba0134 Mon Sep 17 00:00:00 2001
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: Fri, 20 Oct 2017 09:30:53 -0500
Subject: [PATCH 52/95] x86/mm: Add DMA support for SEV memory encryption
DMA access to encrypted memory cannot be performed when SEV is active.
In order for DMA to properly work when SEV is active, the SWIOTLB bounce
buffers must be used.
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>C
Tested-by: Borislav Petkov <bp@suse.de>
Cc: kvm@vger.kernel.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Link: https://lkml.kernel.org/r/20171020143059.3291-12-brijesh.singh@amd.com
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
---
arch/x86/mm/mem_encrypt.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++
lib/swiotlb.c | 5 +--
2 files changed, 89 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/mem_encrypt.c b/arch/x86/mm/mem_encrypt.c
index 4e4a304..3c82d64 100755
--- a/arch/x86/mm/mem_encrypt.c
+++ b/arch/x86/mm/mem_encrypt.c
@@ -192,6 +192,70 @@ void __init sme_early_init(void)
/* Update the protection map with memory encryption mask */
for (i = 0; i < ARRAY_SIZE(protection_map); i++)
protection_map[i] = pgprot_encrypted(protection_map[i]);
+
+ if (sev_active())
+ swiotlb_force = SWIOTLB_FORCE;
+}
+
+static void *sev_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
+ gfp_t gfp, unsigned long attrs)
+{
+ unsigned long dma_mask;
+ unsigned int order;
+ struct page *page;
+ void *vaddr = NULL;
+
+ dma_mask = dma_alloc_coherent_mask(dev, gfp);
+ order = get_order(size);
+
+ /*
+ * Memory will be memset to zero after marking decrypted, so don't
+ * bother clearing it before.
+ */
+ gfp &= ~__GFP_ZERO;
+
+ page = alloc_pages_node(dev_to_node(dev), gfp, order);
+ if (page) {
+ dma_addr_t addr;
+
+ /*
+ * Since we will be clearing the encryption bit, check the
+ * mask with it already cleared.
+ */
+ addr = __sme_clr(phys_to_dma(dev, page_to_phys(page)));
+ if ((addr + size) > dma_mask) {
+ __free_pages(page, get_order(size));
+ } else {
+ vaddr = page_address(page);
+ *dma_handle = addr;
+ }
+ }
+
+ if (!vaddr)
+ vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, gfp);
+
+ if (!vaddr)
+ return NULL;
+
+ /* Clear the SME encryption bit for DMA use if not swiotlb area */
+ if (!is_swiotlb_buffer(dma_to_phys(dev, *dma_handle))) {
+ set_memory_decrypted((unsigned long)vaddr, 1 << order);
+ memset(vaddr, 0, PAGE_SIZE << order);
+ *dma_handle = __sme_clr(*dma_handle);
+ }
+
+ return vaddr;
+}
+
+static void sev_free(struct device *dev, size_t size, void *vaddr,
+ dma_addr_t dma_handle, unsigned long attrs)
+{
+ /* Set the SME encryption bit for re-use if not swiotlb area */
+ if (!is_swiotlb_buffer(dma_to_phys(dev, dma_handle)))
+ set_memory_encrypted((unsigned long)vaddr,
+ 1 << get_order(size));
+
+ swiotlb_free_coherent(dev, size, vaddr, dma_handle);
}
/*
@@ -218,6 +282,20 @@ bool sev_active(void)
}
EXPORT_SYMBOL_GPL(sev_active);
+static const struct dma_map_ops sev_dma_ops = {
+ .alloc = sev_alloc,
+ .free = sev_free,
+ .map_page = swiotlb_map_page,
+ .unmap_page = swiotlb_unmap_page,
+ .map_sg = swiotlb_map_sg_attrs,
+ .unmap_sg = swiotlb_unmap_sg_attrs,
+ .sync_single_for_cpu = swiotlb_sync_single_for_cpu,
+ .sync_single_for_device = swiotlb_sync_single_for_device,
+ .sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
+ .sync_sg_for_device = swiotlb_sync_sg_for_device,
+ .mapping_error = swiotlb_dma_mapping_error,
+};
+
/* Architecture __weak replacement functions */
void __init mem_encrypt_init(void)
{
@@ -227,6 +305,14 @@ void __init mem_encrypt_init(void)
/* Call into SWIOTLB to update the SWIOTLB DMA buffers */
swiotlb_update_mem_attributes();
+ /*
+ * With SEV, DMA operations cannot use encryption. New DMA ops
+ * are required in order to mark the DMA areas as decrypted or
+ * to use bounce buffers.
+ */
+ if (sev_active())
+ dma_ops = &sev_dma_ops;
+
pr_info("AMD Secure Memory Encryption (SME) active\n");
}
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 20df2fd..0d7f46f 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -507,8 +507,9 @@ phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
if (no_iotlb_memory)
panic("Can not allocate SWIOTLB buffer earlier and can't now provide you with the DMA bounce buffer");
- if (sme_active())
- pr_warn_once("SME is active and system is using DMA bounce buffers\n");
+ if (mem_encrypt_active())
+ pr_warn_once("%s is active and system is using DMA bounce buffers\n",
+ sme_active() ? "SME" : "SEV");
mask = dma_get_seg_boundary(hwdev);
--
2.7.4
|
