xen-vtx-unstable

annotate linux-2.6-xen-sparse/arch/xen/kernel/gnttab.c @ 6339:1d86fcb11b59

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Grant table updates for block device changes.
- add gnttab_free_grant_reference
- make gnttab_free_grant_references interface consistent with other gnttab
functions
- add support for callback when references are freed
Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk>
author cl349@firebug.cl.cam.ac.uk
date Mon Aug 22 20:52:38 2005 +0000 (2005-08-22)
parents f294acb25858
children 2d3a7be68ba3
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>
kaf24@5402 22 #include <asm-xen/synch_bitops.h>
cl349@4693 23
cl349@4693 24 #if 1
cl349@4693 25 #define ASSERT(_p) \
cl349@4693 26 if ( !(_p) ) { printk(KERN_ALERT"Assertion '%s': line %d, file %s\n", \
cl349@4693 27 #_p , __LINE__, __FILE__); *(int*)0=0; }
cl349@4693 28 #else
cl349@4693 29 #define ASSERT(_p) ((void)0)
cl349@4693 30 #endif
cl349@4693 31
cl349@4693 32 #define WPRINTK(fmt, args...) \
cl349@4693 33 printk(KERN_WARNING "xen_grant: " fmt, ##args)
cl349@4693 34
cl349@4693 35
cl349@4693 36 EXPORT_SYMBOL(gnttab_grant_foreign_access);
cl349@4693 37 EXPORT_SYMBOL(gnttab_end_foreign_access);
cl349@4693 38 EXPORT_SYMBOL(gnttab_query_foreign_access);
cl349@4693 39 EXPORT_SYMBOL(gnttab_grant_foreign_transfer);
cl349@4693 40 EXPORT_SYMBOL(gnttab_end_foreign_transfer);
cl349@4693 41 EXPORT_SYMBOL(gnttab_alloc_grant_references);
cl349@4693 42 EXPORT_SYMBOL(gnttab_free_grant_references);
cl349@4693 43 EXPORT_SYMBOL(gnttab_claim_grant_reference);
cl349@4693 44 EXPORT_SYMBOL(gnttab_release_grant_reference);
cl349@4693 45 EXPORT_SYMBOL(gnttab_grant_foreign_access_ref);
cl349@4693 46 EXPORT_SYMBOL(gnttab_grant_foreign_transfer_ref);
cl349@4693 47
cl349@4693 48 static grant_ref_t gnttab_free_list[NR_GRANT_ENTRIES];
cl349@4693 49 static grant_ref_t gnttab_free_head;
cl349@4693 50
cl349@4693 51 static grant_entry_t *shared;
cl349@4693 52
cl349@6339 53 static struct gnttab_free_callback *gnttab_free_callback_list = NULL;
cl349@6339 54
cl349@4693 55 /*
cl349@4693 56 * Lock-free grant-entry allocator
cl349@4693 57 */
cl349@4693 58
cl349@4693 59 static inline int
cl349@4693 60 get_free_entry(
cl349@4693 61 void)
cl349@4693 62 {
cl349@4693 63 grant_ref_t fh, nfh = gnttab_free_head;
cl349@4693 64 do { if ( unlikely((fh = nfh) == NR_GRANT_ENTRIES) ) return -1; }
cl349@4693 65 while ( unlikely((nfh = cmpxchg(&gnttab_free_head, fh,
cl349@4693 66 gnttab_free_list[fh])) != fh) );
cl349@4693 67 return fh;
cl349@4693 68 }
cl349@4693 69
cl349@6339 70 static void do_free_callbacks(void)
cl349@6339 71 {
cl349@6339 72 struct gnttab_free_callback *callback = gnttab_free_callback_list;
cl349@6339 73 gnttab_free_callback_list = NULL;
cl349@6339 74 while (callback) {
cl349@6339 75 schedule_work(callback->work);
cl349@6339 76 callback = callback->next;
cl349@6339 77 }
cl349@6339 78 }
cl349@6339 79
cl349@4693 80 static inline void
cl349@4693 81 put_free_entry(
cl349@4693 82 grant_ref_t ref)
cl349@4693 83 {
cl349@4693 84 grant_ref_t fh, nfh = gnttab_free_head;
cl349@4693 85 do { gnttab_free_list[ref] = fh = nfh; wmb(); }
cl349@4693 86 while ( unlikely((nfh = cmpxchg(&gnttab_free_head, fh, ref)) != fh) );
cl349@6339 87 if ( unlikely(gnttab_free_callback_list) )
cl349@6339 88 do_free_callbacks();
cl349@4693 89 }
cl349@4693 90
cl349@4693 91 /*
cl349@4693 92 * Public grant-issuing interface functions
cl349@4693 93 */
cl349@4693 94
cl349@4693 95 int
cl349@4693 96 gnttab_grant_foreign_access(
cl349@4693 97 domid_t domid, unsigned long frame, int readonly)
cl349@4693 98 {
cl349@4693 99 int ref;
cl349@4693 100
cl349@4693 101 if ( unlikely((ref = get_free_entry()) == -1) )
cl349@4693 102 return -ENOSPC;
cl349@4693 103
cl349@4693 104 shared[ref].frame = frame;
cl349@4693 105 shared[ref].domid = domid;
cl349@4693 106 wmb();
cl349@4693 107 shared[ref].flags = GTF_permit_access | (readonly ? GTF_readonly : 0);
cl349@4693 108
cl349@4693 109 return ref;
cl349@4693 110 }
cl349@4693 111
cl349@4693 112 void
cl349@4693 113 gnttab_grant_foreign_access_ref(
cl349@4693 114 grant_ref_t ref, domid_t domid, unsigned long frame, int readonly)
cl349@4693 115 {
cl349@4693 116 shared[ref].frame = frame;
cl349@4693 117 shared[ref].domid = domid;
cl349@4693 118 wmb();
cl349@4693 119 shared[ref].flags = GTF_permit_access | (readonly ? GTF_readonly : 0);
cl349@4693 120 }
cl349@4693 121
cl349@4693 122
cl349@4693 123 int
cl349@4693 124 gnttab_query_foreign_access( grant_ref_t ref )
cl349@4693 125 {
cl349@4693 126 u16 nflags;
cl349@4693 127
cl349@4693 128 nflags = shared[ref].flags;
cl349@4693 129
cl349@4693 130 return ( nflags & (GTF_reading|GTF_writing) );
cl349@4693 131 }
cl349@4693 132
cl349@4693 133 void
cl349@4693 134 gnttab_end_foreign_access( grant_ref_t ref, int readonly )
cl349@4693 135 {
cl349@4693 136 u16 flags, nflags;
cl349@4693 137
cl349@4693 138 nflags = shared[ref].flags;
cl349@4693 139 do {
cl349@4693 140 if ( (flags = nflags) & (GTF_reading|GTF_writing) )
cl349@4693 141 printk(KERN_ALERT "WARNING: g.e. still in use!\n");
cl349@4693 142 }
sos22@5391 143 while ( (nflags = synch_cmpxchg(&shared[ref].flags, flags, 0)) != flags );
cl349@4693 144
cl349@4693 145 put_free_entry(ref);
cl349@4693 146 }
cl349@4693 147
cl349@4693 148 int
cl349@4693 149 gnttab_grant_foreign_transfer(
cl349@4693 150 domid_t domid, unsigned long pfn )
cl349@4693 151 {
cl349@4693 152 int ref;
cl349@4693 153
cl349@4693 154 if ( unlikely((ref = get_free_entry()) == -1) )
cl349@4693 155 return -ENOSPC;
cl349@4693 156
cl349@4693 157 shared[ref].frame = pfn;
cl349@4693 158 shared[ref].domid = domid;
cl349@4693 159 wmb();
cl349@4693 160 shared[ref].flags = GTF_accept_transfer;
cl349@4693 161
cl349@4693 162 return ref;
cl349@4693 163 }
cl349@4693 164
cl349@4693 165 void
cl349@4693 166 gnttab_grant_foreign_transfer_ref(
cl349@4693 167 grant_ref_t ref, domid_t domid, unsigned long pfn )
cl349@4693 168 {
cl349@4693 169 shared[ref].frame = pfn;
cl349@4693 170 shared[ref].domid = domid;
cl349@4693 171 wmb();
cl349@4693 172 shared[ref].flags = GTF_accept_transfer;
cl349@4693 173 }
cl349@4693 174
cl349@4693 175 unsigned long
cl349@4693 176 gnttab_end_foreign_transfer(
cl349@4693 177 grant_ref_t ref)
cl349@4693 178 {
cl349@4693 179 unsigned long frame = 0;
cl349@4693 180 u16 flags;
cl349@4693 181
cl349@4693 182 flags = shared[ref].flags;
vh249@5828 183 #ifdef CONFIG_XEN_NETDEV_GRANT_RX
vh249@5828 184 /*
vh249@5828 185 * But can't flags == (GTF_accept_transfer | GTF_transfer_completed)
vh249@5828 186 * if gnttab_donate executes without interruption???
vh249@5828 187 */
vh249@5828 188 #else
cl349@4693 189 ASSERT(flags == (GTF_accept_transfer | GTF_transfer_committed));
vh249@5828 190 #endif
cl349@4693 191 /*
cl349@4693 192 * If a transfer is committed then wait for the frame address to appear.
cl349@4693 193 * Otherwise invalidate the grant entry against future use.
cl349@4693 194 */
cl349@4693 195 if ( likely(flags != GTF_accept_transfer) ||
sos22@5391 196 (synch_cmpxchg(&shared[ref].flags, flags, 0) != GTF_accept_transfer) )
cl349@4693 197 while ( unlikely((frame = shared[ref].frame) == 0) )
cl349@4693 198 cpu_relax();
cl349@4693 199
cl349@4693 200 put_free_entry(ref);
cl349@4693 201
cl349@4693 202 return frame;
cl349@4693 203 }
cl349@4693 204
cl349@4693 205 void
cl349@6339 206 gnttab_free_grant_reference( grant_ref_t ref )
cl349@6339 207 {
cl349@6339 208
cl349@6339 209 put_free_entry(ref);
cl349@6339 210 }
cl349@6339 211
cl349@6339 212 void
cl349@6339 213 gnttab_free_grant_references( grant_ref_t *head,
cl349@6339 214 grant_ref_t terminal )
cl349@4693 215 {
cl349@4693 216 /* TODO: O(N)...? */
cl349@6339 217 grant_ref_t ref;
cl349@4693 218
cl349@6339 219 while (*head != terminal) {
cl349@6339 220 ref = *head;
cl349@6339 221 *head = gnttab_free_list[*head];
cl349@6339 222 put_free_entry(ref);
vh249@5272 223 }
cl349@4693 224 }
cl349@4693 225
cl349@4693 226 int
cl349@4693 227 gnttab_alloc_grant_references( u16 count,
cl349@4693 228 grant_ref_t *head,
cl349@4693 229 grant_ref_t *terminal )
cl349@4693 230 {
cl349@4693 231 int i;
cl349@4693 232 grant_ref_t h = gnttab_free_head;
cl349@4693 233
cl349@4693 234 for ( i = 0; i < count; i++ )
cl349@4693 235 if ( unlikely(get_free_entry() == -1) )
cl349@4693 236 goto not_enough_refs;
cl349@4693 237
cl349@4693 238 *head = h;
cl349@4693 239 *terminal = gnttab_free_head;
cl349@4693 240
cl349@4693 241 return 0;
cl349@4693 242
cl349@4693 243 not_enough_refs:
cl349@4693 244 gnttab_free_head = h;
cl349@4693 245 return -ENOSPC;
cl349@4693 246 }
cl349@4693 247
cl349@4693 248 int
cl349@4693 249 gnttab_claim_grant_reference( grant_ref_t *private_head,
cl349@4693 250 grant_ref_t terminal )
cl349@4693 251 {
cl349@4693 252 grant_ref_t g;
cl349@4693 253 if ( unlikely((g = *private_head) == terminal) )
cl349@4693 254 return -ENOSPC;
cl349@4693 255 *private_head = gnttab_free_list[g];
cl349@4693 256 return g;
cl349@4693 257 }
cl349@4693 258
cl349@4693 259 void
cl349@4693 260 gnttab_release_grant_reference( grant_ref_t *private_head,
cl349@4693 261 grant_ref_t release )
cl349@4693 262 {
cl349@4693 263 gnttab_free_list[release] = *private_head;
cl349@4693 264 *private_head = release;
cl349@4693 265 }
cl349@4693 266
cl349@6339 267 void
cl349@6339 268 gnttab_request_free_callback(struct gnttab_free_callback *callback,
cl349@6339 269 struct work_struct *work)
cl349@6339 270 {
cl349@6339 271 callback->work = work;
cl349@6339 272 callback->next = gnttab_free_callback_list;
cl349@6339 273 gnttab_free_callback_list = callback;
cl349@6339 274 }
cl349@6339 275
cl349@4693 276 /*
cl349@4693 277 * ProcFS operations
cl349@4693 278 */
cl349@4693 279
cl349@4693 280 #ifdef CONFIG_PROC_FS
cl349@4693 281
cl349@4693 282 static struct proc_dir_entry *grant_pde;
cl349@4693 283
cl349@4693 284 static int grant_ioctl(struct inode *inode, struct file *file,
cl349@4693 285 unsigned int cmd, unsigned long data)
cl349@4693 286 {
cl349@4693 287 int ret;
cl349@4693 288 privcmd_hypercall_t hypercall;
cl349@4693 289
cl349@4693 290 /* XXX Need safety checks here if using for anything other
cl349@4693 291 * than debugging */
cl349@4693 292 return -ENOSYS;
cl349@4693 293
cl349@4693 294 if ( cmd != IOCTL_PRIVCMD_HYPERCALL )
cl349@4693 295 return -ENOSYS;
cl349@4693 296
cl349@4693 297 if ( copy_from_user(&hypercall, (void *)data, sizeof(hypercall)) )
cl349@4693 298 return -EFAULT;
cl349@4693 299
cl349@4693 300 if ( hypercall.op != __HYPERVISOR_grant_table_op )
cl349@4693 301 return -ENOSYS;
cl349@4693 302
cl349@4693 303 /* hypercall-invoking asm taken from privcmd.c */
cl349@4693 304 __asm__ __volatile__ (
cl349@4693 305 "pushl %%ebx; pushl %%ecx; pushl %%edx; pushl %%esi; pushl %%edi; "
cl349@4693 306 "movl 4(%%eax),%%ebx ;"
cl349@4693 307 "movl 8(%%eax),%%ecx ;"
cl349@4693 308 "movl 12(%%eax),%%edx ;"
cl349@4693 309 "movl 16(%%eax),%%esi ;"
cl349@4693 310 "movl 20(%%eax),%%edi ;"
cl349@4693 311 "movl (%%eax),%%eax ;"
cl349@4693 312 TRAP_INSTR "; "
cl349@4693 313 "popl %%edi; popl %%esi; popl %%edx; popl %%ecx; popl %%ebx"
cl349@4693 314 : "=a" (ret) : "0" (&hypercall) : "memory" );
cl349@4693 315
cl349@4693 316 return ret;
cl349@4693 317 }
cl349@4693 318
cl349@4693 319 static struct file_operations grant_file_ops = {
cl349@4693 320 ioctl: grant_ioctl,
cl349@4693 321 };
cl349@4693 322
cl349@4693 323 static int grant_read(char *page, char **start, off_t off,
cl349@4693 324 int count, int *eof, void *data)
cl349@4693 325 {
cl349@4693 326 int len;
cl349@4693 327 unsigned int i;
cl349@4693 328 grant_entry_t *gt;
cl349@4693 329
cl349@4693 330 gt = (grant_entry_t *)shared;
cl349@4693 331 len = 0;
cl349@4693 332
cl349@4693 333 for ( i = 0; i < NR_GRANT_ENTRIES; i++ )
cl349@4693 334 /* TODO: safety catch here until this can handle >PAGE_SIZE output */
cl349@4693 335 if (len > (PAGE_SIZE - 200))
cl349@4693 336 {
cl349@4693 337 len += sprintf( page + len, "Truncated.\n");
cl349@4693 338 break;
cl349@4693 339 }
cl349@4693 340
cl349@4693 341 if ( gt[i].flags )
cl349@4693 342 len += sprintf( page + len,
cl349@4693 343 "Grant: ref (0x%x) flags (0x%hx) dom (0x%hx) frame (0x%x)\n",
cl349@4693 344 i,
cl349@4693 345 gt[i].flags,
cl349@4693 346 gt[i].domid,
cl349@4693 347 gt[i].frame );
cl349@4693 348
cl349@4693 349 *eof = 1;
cl349@4693 350 return len;
cl349@4693 351 }
cl349@4693 352
cl349@4693 353 static int grant_write(struct file *file, const char __user *buffer,
cl349@4693 354 unsigned long count, void *data)
cl349@4693 355 {
cl349@4693 356 /* TODO: implement this */
cl349@4693 357 return -ENOSYS;
cl349@4693 358 }
cl349@4693 359
cl349@4693 360 #endif /* CONFIG_PROC_FS */
cl349@4693 361
cl349@4693 362 int gnttab_resume(void)
cl349@4693 363 {
cl349@4693 364 gnttab_setup_table_t setup;
cl349@4693 365 unsigned long frames[NR_GRANT_FRAMES];
cl349@4693 366 int i;
cl349@4693 367
cl349@4693 368 setup.dom = DOMID_SELF;
cl349@4693 369 setup.nr_frames = NR_GRANT_FRAMES;
cl349@4693 370 setup.frame_list = frames;
cl349@4693 371
cl349@4693 372 BUG_ON(HYPERVISOR_grant_table_op(GNTTABOP_setup_table, &setup, 1) != 0);
cl349@4693 373 BUG_ON(setup.status != 0);
cl349@4693 374
cl349@4693 375 for ( i = 0; i < NR_GRANT_FRAMES; i++ )
cl349@4777 376 set_fixmap(FIX_GNTTAB_END - i, frames[i] << PAGE_SHIFT);
cl349@4693 377
cl349@4693 378 return 0;
cl349@4693 379 }
cl349@4693 380
cl349@4693 381 int gnttab_suspend(void)
cl349@4693 382 {
cl349@4693 383 int i;
cl349@4693 384
cl349@4693 385 for ( i = 0; i < NR_GRANT_FRAMES; i++ )
cl349@4693 386 clear_fixmap(FIX_GNTTAB_END - i);
cl349@4693 387
cl349@4693 388 return 0;
cl349@4693 389 }
cl349@4693 390
cl349@4693 391 static int __init gnttab_init(void)
cl349@4693 392 {
cl349@4693 393 int i;
cl349@4693 394
cl349@4693 395 BUG_ON(gnttab_resume());
cl349@4693 396
cl349@4693 397 shared = (grant_entry_t *)fix_to_virt(FIX_GNTTAB_END);
cl349@4693 398
cl349@4693 399 for ( i = 0; i < NR_GRANT_ENTRIES; i++ )
cl349@4693 400 gnttab_free_list[i] = i + 1;
cl349@4693 401
cl349@4693 402 #ifdef CONFIG_PROC_FS
cl349@4693 403 /*
cl349@4693 404 * /proc/xen/grant : used by libxc to access grant tables
cl349@4693 405 */
cl349@4693 406 if ( (grant_pde = create_xen_proc_entry("grant", 0600)) == NULL )
cl349@4693 407 {
cl349@4693 408 WPRINTK("Unable to create grant xen proc entry\n");
cl349@4693 409 return -1;
cl349@4693 410 }
cl349@4693 411
cl349@4693 412 grant_file_ops.read = grant_pde->proc_fops->read;
cl349@4693 413 grant_file_ops.write = grant_pde->proc_fops->write;
cl349@4693 414
cl349@4693 415 grant_pde->proc_fops = &grant_file_ops;
cl349@4693 416
cl349@4693 417 grant_pde->read_proc = &grant_read;
cl349@4693 418 grant_pde->write_proc = &grant_write;
cl349@4693 419 #endif
cl349@4693 420
cl349@4693 421 printk("Grant table initialized\n");
cl349@4693 422 return 0;
cl349@4693 423 }
cl349@4693 424
cl349@4693 425 __initcall(gnttab_init);