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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
From 8a49eeabdeed5b414efeb82c97ba44278e591819 Mon Sep 17 00:00:00 2001
From: Tom Lendacky <thomas.lendacky@amd.com>
Date: Fri, 20 Oct 2017 09:30:52 -0500
Subject: [PATCH 51/95] x86/mm, resource: Use PAGE_KERNEL protection for
ioremap of memory pages
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
In order for memory pages to be properly mapped when SEV is active, it's
necessary to use the PAGE_KERNEL protection attribute as the base
protection. This ensures that memory mapping of, e.g. ACPI tables,
receives the proper mapping attributes.
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>
Tested-by: Borislav Petkov <bp@suse.de>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: kvm@vger.kernel.org
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Link: https://lkml.kernel.org/r/20171020143059.3291-11-brijesh.singh@amd.com
Signed-off-by: Sudheesh Mavila <sudheesh.mavila@amd.com>
---
arch/x86/mm/ioremap.c | 79 ++++++++++++++++++++++++++++++++++++++++++--------
include/linux/ioport.h | 3 ++
kernel/resource.c | 19 ++++++++++++
3 files changed, 89 insertions(+), 12 deletions(-)
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index f0b91a2..e2db83b 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -27,6 +27,11 @@
#include "physaddr.h"
+struct ioremap_mem_flags {
+ bool system_ram;
+ bool desc_other;
+};
+
/*
* Fix up the linear direct mapping of the kernel to avoid cache attribute
* conflicts.
@@ -56,17 +61,59 @@ int ioremap_change_attr(unsigned long vaddr, unsigned long size,
return err;
}
-static int __ioremap_check_ram(unsigned long start_pfn, unsigned long nr_pages,
- void *arg)
+static bool __ioremap_check_ram(struct resource *res)
{
+ unsigned long start_pfn, stop_pfn;
unsigned long i;
- for (i = 0; i < nr_pages; ++i)
- if (pfn_valid(start_pfn + i) &&
- !PageReserved(pfn_to_page(start_pfn + i)))
- return 1;
+ if ((res->flags & IORESOURCE_SYSTEM_RAM) != IORESOURCE_SYSTEM_RAM)
+ return false;
- return 0;
+ start_pfn = (res->start + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ stop_pfn = (res->end + 1) >> PAGE_SHIFT;
+ if (stop_pfn > start_pfn) {
+ for (i = 0; i < (stop_pfn - start_pfn); ++i)
+ if (pfn_valid(start_pfn + i) &&
+ !PageReserved(pfn_to_page(start_pfn + i)))
+ return true;
+ }
+
+ return false;
+}
+
+static int __ioremap_check_desc_other(struct resource *res)
+{
+ return (res->desc != IORES_DESC_NONE);
+}
+
+static int __ioremap_res_check(struct resource *res, void *arg)
+{
+ struct ioremap_mem_flags *flags = arg;
+
+ if (!flags->system_ram)
+ flags->system_ram = __ioremap_check_ram(res);
+
+ if (!flags->desc_other)
+ flags->desc_other = __ioremap_check_desc_other(res);
+
+ return flags->system_ram && flags->desc_other;
+}
+
+/*
+ * To avoid multiple resource walks, this function walks resources marked as
+ * IORESOURCE_MEM and IORESOURCE_BUSY and looking for system RAM and/or a
+ * resource described not as IORES_DESC_NONE (e.g. IORES_DESC_ACPI_TABLES).
+ */
+static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
+ struct ioremap_mem_flags *flags)
+{
+ u64 start, end;
+
+ start = (u64)addr;
+ end = start + size - 1;
+ memset(flags, 0, sizeof(*flags));
+
+ walk_mem_res(start, end, flags, __ioremap_res_check);
}
/*
@@ -87,9 +134,10 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
unsigned long size, enum page_cache_mode pcm, void *caller)
{
unsigned long offset, vaddr;
- resource_size_t pfn, last_pfn, last_addr;
+ resource_size_t last_addr;
const resource_size_t unaligned_phys_addr = phys_addr;
const unsigned long unaligned_size = size;
+ struct ioremap_mem_flags mem_flags;
struct vm_struct *area;
enum page_cache_mode new_pcm;
pgprot_t prot;
@@ -108,13 +156,12 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
return NULL;
}
+ __ioremap_check_mem(phys_addr, size, &mem_flags);
+
/*
* Don't allow anybody to remap normal RAM that we're using..
*/
- pfn = phys_addr >> PAGE_SHIFT;
- last_pfn = last_addr >> PAGE_SHIFT;
- if (walk_system_ram_range(pfn, last_pfn - pfn + 1, NULL,
- __ioremap_check_ram) == 1) {
+ if (mem_flags.system_ram) {
WARN_ONCE(1, "ioremap on RAM at %pa - %pa\n",
&phys_addr, &last_addr);
return NULL;
@@ -146,7 +193,15 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
pcm = new_pcm;
}
+ /*
+ * If the page being mapped is in memory and SEV is active then
+ * make sure the memory encryption attribute is enabled in the
+ * resulting mapping.
+ */
prot = PAGE_KERNEL_IO;
+ if (sev_active() && mem_flags.desc_other)
+ prot = pgprot_encrypted(prot);
+
switch (pcm) {
case _PAGE_CACHE_MODE_UC:
default:
diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index c0070d7..93b4183 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -271,6 +271,9 @@ extern int
walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
void *arg, int (*func)(unsigned long, unsigned long, void *));
extern int
+walk_mem_res(u64 start, u64 end, void *arg,
+ int (*func)(struct resource *, void *));
+extern int
walk_system_ram_res(u64 start, u64 end, void *arg,
int (*func)(struct resource *, void *));
extern int
diff --git a/kernel/resource.c b/kernel/resource.c
index 78cae82..790f1b8 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -397,6 +397,8 @@ static int find_next_iomem_res(struct resource *res, unsigned long desc,
res->start = p->start;
if (res->end > p->end)
res->end = p->end;
+ res->flags = p->flags;
+ res->desc = p->desc;
return 0;
}
@@ -467,6 +469,23 @@ int walk_system_ram_res(u64 start, u64 end, void *arg,
arg, func);
}
+/*
+ * This function calls the @func callback against all memory ranges, which
+ * are ranges marked as IORESOURCE_MEM and IORESOUCE_BUSY.
+ */
+int walk_mem_res(u64 start, u64 end, void *arg,
+ int (*func)(struct resource *, void *))
+{
+ struct resource res;
+
+ res.start = start;
+ res.end = end;
+ res.flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+ return __walk_iomem_res_desc(&res, IORES_DESC_NONE, true,
+ arg, func);
+}
+
#if !defined(CONFIG_ARCH_HAS_WALK_MEMORY)
/*
--
2.7.4
|
