xen-vtx-unstable

annotate linux-2.6.11-xen-sparse/arch/xen/kernel/gnttab.c @ 4693:2f776687450f

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bitkeeper revision 1.1389.2.2 (42714ca83Gv7CX98R4gC0TU3w-pX1Q)

Merge xen-2.0-testing "sync w/ unstable" changes.
author cl349@firebug.cl.cam.ac.uk
date Thu Apr 28 20:50:48 2005 +0000 (2005-04-28)
parents
children f23e5c9c3f1b
rev   line source
cl349@4693 1 /******************************************************************************
cl349@4693 2 * gnttab.c
cl349@4693 3 *
cl349@4693 4 * Two sets of functionality:
cl349@4693 5 * 1. Granting foreign access to our memory reservation.
cl349@4693 6 * 2. Accessing others' memory reservations via grant references.
cl349@4693 7 * (i.e., mechanisms for both sender and recipient of grant references)
cl349@4693 8 *
cl349@4693 9 * Copyright (c) 2005, Christopher Clark
cl349@4693 10 * Copyright (c) 2004, K A Fraser
cl349@4693 11 */
cl349@4693 12
cl349@4693 13 #include <linux/config.h>
cl349@4693 14 #include <linux/module.h>
cl349@4693 15 #include <linux/sched.h>
cl349@4693 16 #include <asm/pgtable.h>
cl349@4693 17 #include <asm/fixmap.h>
cl349@4693 18 #include <asm/uaccess.h>
cl349@4693 19 #include <asm-xen/xen_proc.h>
cl349@4693 20 #include <asm-xen/linux-public/privcmd.h>
cl349@4693 21 #include <asm-xen/gnttab.h>
cl349@4693 22
cl349@4693 23 #ifndef set_fixmap_ma
cl349@4693 24 #define set_fixmap_ma set_fixmap
cl349@4693 25 #endif
cl349@4693 26
cl349@4693 27 #if 1
cl349@4693 28 #define ASSERT(_p) \
cl349@4693 29 if ( !(_p) ) { printk(KERN_ALERT"Assertion '%s': line %d, file %s\n", \
cl349@4693 30 #_p , __LINE__, __FILE__); *(int*)0=0; }
cl349@4693 31 #else
cl349@4693 32 #define ASSERT(_p) ((void)0)
cl349@4693 33 #endif
cl349@4693 34
cl349@4693 35 #define WPRINTK(fmt, args...) \
cl349@4693 36 printk(KERN_WARNING "xen_grant: " fmt, ##args)
cl349@4693 37
cl349@4693 38
cl349@4693 39 EXPORT_SYMBOL(gnttab_grant_foreign_access);
cl349@4693 40 EXPORT_SYMBOL(gnttab_end_foreign_access);
cl349@4693 41 EXPORT_SYMBOL(gnttab_query_foreign_access);
cl349@4693 42 EXPORT_SYMBOL(gnttab_grant_foreign_transfer);
cl349@4693 43 EXPORT_SYMBOL(gnttab_end_foreign_transfer);
cl349@4693 44 EXPORT_SYMBOL(gnttab_alloc_grant_references);
cl349@4693 45 EXPORT_SYMBOL(gnttab_free_grant_references);
cl349@4693 46 EXPORT_SYMBOL(gnttab_claim_grant_reference);
cl349@4693 47 EXPORT_SYMBOL(gnttab_release_grant_reference);
cl349@4693 48 EXPORT_SYMBOL(gnttab_grant_foreign_access_ref);
cl349@4693 49 EXPORT_SYMBOL(gnttab_grant_foreign_transfer_ref);
cl349@4693 50
cl349@4693 51 static grant_ref_t gnttab_free_list[NR_GRANT_ENTRIES];
cl349@4693 52 static grant_ref_t gnttab_free_head;
cl349@4693 53
cl349@4693 54 static grant_entry_t *shared;
cl349@4693 55
cl349@4693 56 /*
cl349@4693 57 * Lock-free grant-entry allocator
cl349@4693 58 */
cl349@4693 59
cl349@4693 60 static inline int
cl349@4693 61 get_free_entry(
cl349@4693 62 void)
cl349@4693 63 {
cl349@4693 64 grant_ref_t fh, nfh = gnttab_free_head;
cl349@4693 65 do { if ( unlikely((fh = nfh) == NR_GRANT_ENTRIES) ) return -1; }
cl349@4693 66 while ( unlikely((nfh = cmpxchg(&gnttab_free_head, fh,
cl349@4693 67 gnttab_free_list[fh])) != fh) );
cl349@4693 68 return fh;
cl349@4693 69 }
cl349@4693 70
cl349@4693 71 static inline void
cl349@4693 72 put_free_entry(
cl349@4693 73 grant_ref_t ref)
cl349@4693 74 {
cl349@4693 75 grant_ref_t fh, nfh = gnttab_free_head;
cl349@4693 76 do { gnttab_free_list[ref] = fh = nfh; wmb(); }
cl349@4693 77 while ( unlikely((nfh = cmpxchg(&gnttab_free_head, fh, ref)) != fh) );
cl349@4693 78 }
cl349@4693 79
cl349@4693 80 /*
cl349@4693 81 * Public grant-issuing interface functions
cl349@4693 82 */
cl349@4693 83
cl349@4693 84 int
cl349@4693 85 gnttab_grant_foreign_access(
cl349@4693 86 domid_t domid, unsigned long frame, int readonly)
cl349@4693 87 {
cl349@4693 88 int ref;
cl349@4693 89
cl349@4693 90 if ( unlikely((ref = get_free_entry()) == -1) )
cl349@4693 91 return -ENOSPC;
cl349@4693 92
cl349@4693 93 shared[ref].frame = frame;
cl349@4693 94 shared[ref].domid = domid;
cl349@4693 95 wmb();
cl349@4693 96 shared[ref].flags = GTF_permit_access | (readonly ? GTF_readonly : 0);
cl349@4693 97
cl349@4693 98 return ref;
cl349@4693 99 }
cl349@4693 100
cl349@4693 101 void
cl349@4693 102 gnttab_grant_foreign_access_ref(
cl349@4693 103 grant_ref_t ref, domid_t domid, unsigned long frame, int readonly)
cl349@4693 104 {
cl349@4693 105 shared[ref].frame = frame;
cl349@4693 106 shared[ref].domid = domid;
cl349@4693 107 wmb();
cl349@4693 108 shared[ref].flags = GTF_permit_access | (readonly ? GTF_readonly : 0);
cl349@4693 109 }
cl349@4693 110
cl349@4693 111
cl349@4693 112 int
cl349@4693 113 gnttab_query_foreign_access( grant_ref_t ref )
cl349@4693 114 {
cl349@4693 115 u16 nflags;
cl349@4693 116
cl349@4693 117 nflags = shared[ref].flags;
cl349@4693 118
cl349@4693 119 return ( nflags & (GTF_reading|GTF_writing) );
cl349@4693 120 }
cl349@4693 121
cl349@4693 122 void
cl349@4693 123 gnttab_end_foreign_access( grant_ref_t ref, int readonly )
cl349@4693 124 {
cl349@4693 125 u16 flags, nflags;
cl349@4693 126
cl349@4693 127 nflags = shared[ref].flags;
cl349@4693 128 do {
cl349@4693 129 if ( (flags = nflags) & (GTF_reading|GTF_writing) )
cl349@4693 130 printk(KERN_ALERT "WARNING: g.e. still in use!\n");
cl349@4693 131 }
cl349@4693 132 while ( (nflags = cmpxchg(&shared[ref].flags, flags, 0)) != flags );
cl349@4693 133
cl349@4693 134 put_free_entry(ref);
cl349@4693 135 }
cl349@4693 136
cl349@4693 137 int
cl349@4693 138 gnttab_grant_foreign_transfer(
cl349@4693 139 domid_t domid, unsigned long pfn )
cl349@4693 140 {
cl349@4693 141 int ref;
cl349@4693 142
cl349@4693 143 if ( unlikely((ref = get_free_entry()) == -1) )
cl349@4693 144 return -ENOSPC;
cl349@4693 145
cl349@4693 146 shared[ref].frame = pfn;
cl349@4693 147 shared[ref].domid = domid;
cl349@4693 148 wmb();
cl349@4693 149 shared[ref].flags = GTF_accept_transfer;
cl349@4693 150
cl349@4693 151 return ref;
cl349@4693 152 }
cl349@4693 153
cl349@4693 154 void
cl349@4693 155 gnttab_grant_foreign_transfer_ref(
cl349@4693 156 grant_ref_t ref, domid_t domid, unsigned long pfn )
cl349@4693 157 {
cl349@4693 158 shared[ref].frame = pfn;
cl349@4693 159 shared[ref].domid = domid;
cl349@4693 160 wmb();
cl349@4693 161 shared[ref].flags = GTF_accept_transfer;
cl349@4693 162 }
cl349@4693 163
cl349@4693 164 unsigned long
cl349@4693 165 gnttab_end_foreign_transfer(
cl349@4693 166 grant_ref_t ref)
cl349@4693 167 {
cl349@4693 168 unsigned long frame = 0;
cl349@4693 169 u16 flags;
cl349@4693 170
cl349@4693 171 flags = shared[ref].flags;
cl349@4693 172 ASSERT(flags == (GTF_accept_transfer | GTF_transfer_committed));
cl349@4693 173
cl349@4693 174 /*
cl349@4693 175 * If a transfer is committed then wait for the frame address to appear.
cl349@4693 176 * Otherwise invalidate the grant entry against future use.
cl349@4693 177 */
cl349@4693 178 if ( likely(flags != GTF_accept_transfer) ||
cl349@4693 179 (cmpxchg(&shared[ref].flags, flags, 0) != GTF_accept_transfer) )
cl349@4693 180 while ( unlikely((frame = shared[ref].frame) == 0) )
cl349@4693 181 cpu_relax();
cl349@4693 182
cl349@4693 183 put_free_entry(ref);
cl349@4693 184
cl349@4693 185 return frame;
cl349@4693 186 }
cl349@4693 187
cl349@4693 188 void
cl349@4693 189 gnttab_free_grant_references( u16 count, grant_ref_t head )
cl349@4693 190 {
cl349@4693 191 /* TODO: O(N)...? */
cl349@4693 192 grant_ref_t to_die = 0, next = head;
cl349@4693 193 int i;
cl349@4693 194
cl349@4693 195 for ( i = 0; i < count; i++ )
cl349@4693 196 to_die = next;
cl349@4693 197 next = gnttab_free_list[next];
cl349@4693 198 put_free_entry( to_die );
cl349@4693 199 }
cl349@4693 200
cl349@4693 201 int
cl349@4693 202 gnttab_alloc_grant_references( u16 count,
cl349@4693 203 grant_ref_t *head,
cl349@4693 204 grant_ref_t *terminal )
cl349@4693 205 {
cl349@4693 206 int i;
cl349@4693 207 grant_ref_t h = gnttab_free_head;
cl349@4693 208
cl349@4693 209 for ( i = 0; i < count; i++ )
cl349@4693 210 if ( unlikely(get_free_entry() == -1) )
cl349@4693 211 goto not_enough_refs;
cl349@4693 212
cl349@4693 213 *head = h;
cl349@4693 214 *terminal = gnttab_free_head;
cl349@4693 215
cl349@4693 216 return 0;
cl349@4693 217
cl349@4693 218 not_enough_refs:
cl349@4693 219 gnttab_free_head = h;
cl349@4693 220 return -ENOSPC;
cl349@4693 221 }
cl349@4693 222
cl349@4693 223 int
cl349@4693 224 gnttab_claim_grant_reference( grant_ref_t *private_head,
cl349@4693 225 grant_ref_t terminal )
cl349@4693 226 {
cl349@4693 227 grant_ref_t g;
cl349@4693 228 if ( unlikely((g = *private_head) == terminal) )
cl349@4693 229 return -ENOSPC;
cl349@4693 230 *private_head = gnttab_free_list[g];
cl349@4693 231 return g;
cl349@4693 232 }
cl349@4693 233
cl349@4693 234 void
cl349@4693 235 gnttab_release_grant_reference( grant_ref_t *private_head,
cl349@4693 236 grant_ref_t release )
cl349@4693 237 {
cl349@4693 238 gnttab_free_list[release] = *private_head;
cl349@4693 239 *private_head = release;
cl349@4693 240 }
cl349@4693 241
cl349@4693 242 /*
cl349@4693 243 * ProcFS operations
cl349@4693 244 */
cl349@4693 245
cl349@4693 246 #ifdef CONFIG_PROC_FS
cl349@4693 247
cl349@4693 248 static struct proc_dir_entry *grant_pde;
cl349@4693 249
cl349@4693 250 static int grant_ioctl(struct inode *inode, struct file *file,
cl349@4693 251 unsigned int cmd, unsigned long data)
cl349@4693 252 {
cl349@4693 253 int ret;
cl349@4693 254 privcmd_hypercall_t hypercall;
cl349@4693 255
cl349@4693 256 /* XXX Need safety checks here if using for anything other
cl349@4693 257 * than debugging */
cl349@4693 258 return -ENOSYS;
cl349@4693 259
cl349@4693 260 if ( cmd != IOCTL_PRIVCMD_HYPERCALL )
cl349@4693 261 return -ENOSYS;
cl349@4693 262
cl349@4693 263 if ( copy_from_user(&hypercall, (void *)data, sizeof(hypercall)) )
cl349@4693 264 return -EFAULT;
cl349@4693 265
cl349@4693 266 if ( hypercall.op != __HYPERVISOR_grant_table_op )
cl349@4693 267 return -ENOSYS;
cl349@4693 268
cl349@4693 269 /* hypercall-invoking asm taken from privcmd.c */
cl349@4693 270 __asm__ __volatile__ (
cl349@4693 271 "pushl %%ebx; pushl %%ecx; pushl %%edx; pushl %%esi; pushl %%edi; "
cl349@4693 272 "movl 4(%%eax),%%ebx ;"
cl349@4693 273 "movl 8(%%eax),%%ecx ;"
cl349@4693 274 "movl 12(%%eax),%%edx ;"
cl349@4693 275 "movl 16(%%eax),%%esi ;"
cl349@4693 276 "movl 20(%%eax),%%edi ;"
cl349@4693 277 "movl (%%eax),%%eax ;"
cl349@4693 278 TRAP_INSTR "; "
cl349@4693 279 "popl %%edi; popl %%esi; popl %%edx; popl %%ecx; popl %%ebx"
cl349@4693 280 : "=a" (ret) : "0" (&hypercall) : "memory" );
cl349@4693 281
cl349@4693 282 return ret;
cl349@4693 283 }
cl349@4693 284
cl349@4693 285 static struct file_operations grant_file_ops = {
cl349@4693 286 ioctl: grant_ioctl,
cl349@4693 287 };
cl349@4693 288
cl349@4693 289 static int grant_read(char *page, char **start, off_t off,
cl349@4693 290 int count, int *eof, void *data)
cl349@4693 291 {
cl349@4693 292 int len;
cl349@4693 293 unsigned int i;
cl349@4693 294 grant_entry_t *gt;
cl349@4693 295
cl349@4693 296 gt = (grant_entry_t *)shared;
cl349@4693 297 len = 0;
cl349@4693 298
cl349@4693 299 for ( i = 0; i < NR_GRANT_ENTRIES; i++ )
cl349@4693 300 /* TODO: safety catch here until this can handle >PAGE_SIZE output */
cl349@4693 301 if (len > (PAGE_SIZE - 200))
cl349@4693 302 {
cl349@4693 303 len += sprintf( page + len, "Truncated.\n");
cl349@4693 304 break;
cl349@4693 305 }
cl349@4693 306
cl349@4693 307 if ( gt[i].flags )
cl349@4693 308 len += sprintf( page + len,
cl349@4693 309 "Grant: ref (0x%x) flags (0x%hx) dom (0x%hx) frame (0x%x)\n",
cl349@4693 310 i,
cl349@4693 311 gt[i].flags,
cl349@4693 312 gt[i].domid,
cl349@4693 313 gt[i].frame );
cl349@4693 314
cl349@4693 315 *eof = 1;
cl349@4693 316 return len;
cl349@4693 317 }
cl349@4693 318
cl349@4693 319 static int grant_write(struct file *file, const char __user *buffer,
cl349@4693 320 unsigned long count, void *data)
cl349@4693 321 {
cl349@4693 322 /* TODO: implement this */
cl349@4693 323 return -ENOSYS;
cl349@4693 324 }
cl349@4693 325
cl349@4693 326 #endif /* CONFIG_PROC_FS */
cl349@4693 327
cl349@4693 328 int gnttab_resume(void)
cl349@4693 329 {
cl349@4693 330 gnttab_setup_table_t setup;
cl349@4693 331 unsigned long frames[NR_GRANT_FRAMES];
cl349@4693 332 int i;
cl349@4693 333
cl349@4693 334 setup.dom = DOMID_SELF;
cl349@4693 335 setup.nr_frames = NR_GRANT_FRAMES;
cl349@4693 336 setup.frame_list = frames;
cl349@4693 337
cl349@4693 338 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1) != 0);
cl349@4693 339 BUG_ON(setup.status != 0);
cl349@4693 340
cl349@4693 341 for ( i = 0; i < NR_GRANT_FRAMES; i++ )
cl349@4693 342 set_fixmap_ma(FIX_GNTTAB_END - i, frames[i] << PAGE_SHIFT);
cl349@4693 343
cl349@4693 344 return 0;
cl349@4693 345 }
cl349@4693 346
cl349@4693 347 int gnttab_suspend(void)
cl349@4693 348 {
cl349@4693 349 int i;
cl349@4693 350
cl349@4693 351 for ( i = 0; i < NR_GRANT_FRAMES; i++ )
cl349@4693 352 clear_fixmap(FIX_GNTTAB_END - i);
cl349@4693 353
cl349@4693 354 return 0;
cl349@4693 355 }
cl349@4693 356
cl349@4693 357 static int __init gnttab_init(void)
cl349@4693 358 {
cl349@4693 359 int i;
cl349@4693 360
cl349@4693 361 BUG_ON(gnttab_resume());
cl349@4693 362
cl349@4693 363 shared = (grant_entry_t *)fix_to_virt(FIX_GNTTAB_END);
cl349@4693 364
cl349@4693 365 for ( i = 0; i < NR_GRANT_ENTRIES; i++ )
cl349@4693 366 gnttab_free_list[i] = i + 1;
cl349@4693 367
cl349@4693 368 #ifdef CONFIG_PROC_FS
cl349@4693 369 /*
cl349@4693 370 * /proc/xen/grant : used by libxc to access grant tables
cl349@4693 371 */
cl349@4693 372 if ( (grant_pde = create_xen_proc_entry("grant", 0600)) == NULL )
cl349@4693 373 {
cl349@4693 374 WPRINTK("Unable to create grant xen proc entry\n");
cl349@4693 375 return -1;
cl349@4693 376 }
cl349@4693 377
cl349@4693 378 grant_file_ops.read = grant_pde->proc_fops->read;
cl349@4693 379 grant_file_ops.write = grant_pde->proc_fops->write;
cl349@4693 380
cl349@4693 381 grant_pde->proc_fops = &grant_file_ops;
cl349@4693 382
cl349@4693 383 grant_pde->read_proc = &grant_read;
cl349@4693 384 grant_pde->write_proc = &grant_write;
cl349@4693 385 #endif
cl349@4693 386
cl349@4693 387 printk("Grant table initialized\n");
cl349@4693 388 return 0;
cl349@4693 389 }
cl349@4693 390
cl349@4693 391 __initcall(gnttab_init);