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 (at) cam.ac.uk) 8 Changes: Grzegorz Milos (gm281 (at) 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 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 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 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 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 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 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 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 215 XenBusGrantEndAccess ( 216 IN XENBUS_PROTOCOL *This, 217 IN grant_ref_t Ref 218 ) 219 { 220 return XenGrantTableEndAccess (Ref); 221 } 222
