1 /** @file
2 Grant Table function implementation.
3
4 Grant Table are used to grant access to certain page of the current
5 VM to an other VM.
6
7 Author: Steven Smith (sos22@cam.ac.uk)
8 Changes: Grzegorz Milos (gm281@cam.ac.uk)
9 Copyright (C) 2006, Cambridge University
10 Copyright (C) 2014, Citrix Ltd.
11
12 Redistribution and use in source and binary forms, with or without
13 modification, are permitted provided that the following conditions
14 are met:
15 1. Redistributions of source code must retain the above copyright
16 notice, this list of conditions and the following disclaimer.
17 2. Redistributions in binary form must reproduce the above copyright
18 notice, this list of conditions and the following disclaimer in the
19 documentation and/or other materials provided with the distribution.
20
21 THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
25 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 SUCH DAMAGE.
32 **/
33 #include "XenBusDxe.h"
34
35 #include <IndustryStandard/Xen/memory.h>
36
37 #include <Library/XenHypercallLib.h>
38 #include <Library/SynchronizationLib.h>
39
40 #include "GrantTable.h"
41
42 #define NR_RESERVED_ENTRIES 8
43
44 /* NR_GRANT_FRAMES must be less than or equal to that configured in Xen */
45 #define NR_GRANT_FRAMES 4
46 #define NR_GRANT_ENTRIES (NR_GRANT_FRAMES * EFI_PAGE_SIZE / sizeof(grant_entry_v1_t))
47
48 STATIC grant_entry_v1_t *GrantTable = NULL;
49 STATIC grant_ref_t GrantList[NR_GRANT_ENTRIES];
50 STATIC EFI_LOCK mGrantListLock;
51 #ifdef GNT_DEBUG
52 STATIC BOOLEAN GrantInUseList[NR_GRANT_ENTRIES];
53 #endif
54
55 STATIC
56 VOID
XenGrantTablePutFreeEntry(grant_ref_t Ref)57 XenGrantTablePutFreeEntry (
58 grant_ref_t Ref
59 )
60 {
61 EfiAcquireLock (&mGrantListLock);
62 #ifdef GNT_DEBUG
63 ASSERT (GrantInUseList[Ref]);
64 GrantInUseList[Ref] = FALSE;
65 #endif
66 GrantList[Ref] = GrantList[0];
67 GrantList[0] = Ref;
68 EfiReleaseLock (&mGrantListLock);
69 }
70
71 STATIC
72 grant_ref_t
XenGrantTableGetFreeEntry(VOID)73 XenGrantTableGetFreeEntry (
74 VOID
75 )
76 {
77 grant_ref_t Ref;
78
79 EfiAcquireLock (&mGrantListLock);
80 Ref = GrantList[0];
81 ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
82 GrantList[0] = GrantList[Ref];
83 #ifdef GNT_DEBUG
84 ASSERT (!GrantInUseList[Ref]);
85 GrantInUseList[Ref] = TRUE;
86 #endif
87 EfiReleaseLock (&mGrantListLock);
88 return Ref;
89 }
90
91 STATIC
92 grant_ref_t
XenGrantTableGrantAccess(IN domid_t DomainId,IN UINTN Frame,IN BOOLEAN ReadOnly)93 XenGrantTableGrantAccess (
94 IN domid_t DomainId,
95 IN UINTN Frame,
96 IN BOOLEAN ReadOnly
97 )
98 {
99 grant_ref_t Ref;
100 UINT16 Flags;
101
102 ASSERT (GrantTable != NULL);
103 Ref = XenGrantTableGetFreeEntry ();
104 GrantTable[Ref].frame = (UINT32)Frame;
105 GrantTable[Ref].domid = DomainId;
106 MemoryFence ();
107 Flags = GTF_permit_access;
108 if (ReadOnly) {
109 Flags |= GTF_readonly;
110 }
111 GrantTable[Ref].flags = Flags;
112
113 return Ref;
114 }
115
116 STATIC
117 EFI_STATUS
XenGrantTableEndAccess(grant_ref_t Ref)118 XenGrantTableEndAccess (
119 grant_ref_t Ref
120 )
121 {
122 UINT16 Flags, OldFlags;
123
124 ASSERT (GrantTable != NULL);
125 ASSERT (Ref >= NR_RESERVED_ENTRIES && Ref < NR_GRANT_ENTRIES);
126
127 OldFlags = GrantTable[Ref].flags;
128 do {
129 if ((Flags = OldFlags) & (GTF_reading | GTF_writing)) {
130 DEBUG ((EFI_D_WARN, "WARNING: g.e. still in use! (%x)\n", Flags));
131 return EFI_NOT_READY;
132 }
133 OldFlags = InterlockedCompareExchange16 (&GrantTable[Ref].flags, Flags, 0);
134 } while (OldFlags != Flags);
135
136 XenGrantTablePutFreeEntry (Ref);
137 return EFI_SUCCESS;
138 }
139
140 VOID
XenGrantTableInit(IN XENBUS_DEVICE * Dev)141 XenGrantTableInit (
142 IN XENBUS_DEVICE *Dev
143 )
144 {
145 xen_add_to_physmap_t Parameters;
146 INTN Index;
147 INTN ReturnCode;
148
149 #ifdef GNT_DEBUG
150 SetMem(GrantInUseList, sizeof (GrantInUseList), 1);
151 #endif
152 EfiInitializeLock (&mGrantListLock, TPL_NOTIFY);
153 for (Index = NR_RESERVED_ENTRIES; Index < NR_GRANT_ENTRIES; Index++) {
154 XenGrantTablePutFreeEntry ((grant_ref_t)Index);
155 }
156
157 GrantTable = (VOID*)(UINTN) Dev->XenIo->GrantTableAddress;
158 for (Index = 0; Index < NR_GRANT_FRAMES; Index++) {
159 Parameters.domid = DOMID_SELF;
160 Parameters.idx = Index;
161 Parameters.space = XENMAPSPACE_grant_table;
162 Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + Index;
163 ReturnCode = XenHypercallMemoryOp (XENMEM_add_to_physmap, &Parameters);
164 if (ReturnCode != 0) {
165 DEBUG ((EFI_D_ERROR,
166 "Xen GrantTable, add_to_physmap hypercall error: %Ld\n",
167 (INT64)ReturnCode));
168 }
169 }
170 }
171
172 VOID
XenGrantTableDeinit(XENBUS_DEVICE * Dev)173 XenGrantTableDeinit (
174 XENBUS_DEVICE *Dev
175 )
176 {
177 INTN ReturnCode, Index;
178 xen_remove_from_physmap_t Parameters;
179
180 if (GrantTable == NULL) {
181 return;
182 }
183
184 for (Index = NR_GRANT_FRAMES - 1; Index >= 0; Index--) {
185 Parameters.domid = DOMID_SELF;
186 Parameters.gpfn = (xen_pfn_t) ((UINTN) GrantTable >> EFI_PAGE_SHIFT) + Index;
187 DEBUG ((EFI_D_INFO, "Xen GrantTable, removing %Lx\n",
188 (UINT64)Parameters.gpfn));
189 ReturnCode = XenHypercallMemoryOp (XENMEM_remove_from_physmap, &Parameters);
190 if (ReturnCode != 0) {
191 DEBUG ((EFI_D_ERROR,
192 "Xen GrantTable, remove_from_physmap hypercall error: %Ld\n",
193 (INT64)ReturnCode));
194 }
195 }
196 GrantTable = NULL;
197 }
198
199 EFI_STATUS
200 EFIAPI
XenBusGrantAccess(IN XENBUS_PROTOCOL * This,IN domid_t DomainId,IN UINTN Frame,IN BOOLEAN ReadOnly,OUT grant_ref_t * RefPtr)201 XenBusGrantAccess (
202 IN XENBUS_PROTOCOL *This,
203 IN domid_t DomainId,
204 IN UINTN Frame, // MFN
205 IN BOOLEAN ReadOnly,
206 OUT grant_ref_t *RefPtr
207 )
208 {
209 *RefPtr = XenGrantTableGrantAccess (DomainId, Frame, ReadOnly);
210 return EFI_SUCCESS;
211 }
212
213 EFI_STATUS
214 EFIAPI
XenBusGrantEndAccess(IN XENBUS_PROTOCOL * This,IN grant_ref_t Ref)215 XenBusGrantEndAccess (
216 IN XENBUS_PROTOCOL *This,
217 IN grant_ref_t Ref
218 )
219 {
220 return XenGrantTableEndAccess (Ref);
221 }
222