1 /* 2 * Machine specific setup for xen 3 * 4 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007 5 */ 6 7 #include <linux/module.h> 8 #include <linux/sched.h> 9 #include <linux/mm.h> 10 #include <linux/pm.h> 11 #include <linux/memblock.h> 12 13 #include <asm/elf.h> 14 #include <asm/vdso.h> 15 #include <asm/e820.h> 16 #include <asm/setup.h> 17 #include <asm/acpi.h> 18 #include <asm/xen/hypervisor.h> 19 #include <asm/xen/hypercall.h> 20 21 #include <xen/xen.h> 22 #include <xen/page.h> 23 #include <xen/interface/callback.h> 24 #include <xen/interface/memory.h> 25 #include <xen/interface/physdev.h> 26 #include <xen/features.h> 27 28 #include "xen-ops.h" 29 #include "vdso.h" 30 31 /* These are code, but not functions. Defined in entry.S */ 32 extern const char xen_hypervisor_callback[]; 33 extern const char xen_failsafe_callback[]; 34 extern void xen_sysenter_target(void); 35 extern void xen_syscall_target(void); 36 extern void xen_syscall32_target(void); 37 38 /* Amount of extra memory space we add to the e820 ranges */ 39 phys_addr_t xen_extra_mem_start, xen_extra_mem_size; 40 41 /* 42 * The maximum amount of extra memory compared to the base size. The 43 * main scaling factor is the size of struct page. At extreme ratios 44 * of base:extra, all the base memory can be filled with page 45 * structures for the extra memory, leaving no space for anything 46 * else. 47 * 48 * 10x seems like a reasonable balance between scaling flexibility and 49 * leaving a practically usable system. 50 */ 51 #define EXTRA_MEM_RATIO (10) 52 53 static void __init xen_add_extra_mem(unsigned long pages) 54 { 55 unsigned long pfn; 56 57 u64 size = (u64)pages * PAGE_SIZE; 58 u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; 59 60 if (!pages) 61 return; 62 63 e820_add_region(extra_start, size, E820_RAM); 64 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 65 66 memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA"); 67 68 xen_extra_mem_size += size; 69 70 xen_max_p2m_pfn = PFN_DOWN(extra_start + size); 71 72 for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++) 73 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 74 } 75 76 static unsigned long __init xen_release_chunk(phys_addr_t start_addr, 77 phys_addr_t end_addr) 78 { 79 struct xen_memory_reservation reservation = { 80 .address_bits = 0, 81 .extent_order = 0, 82 .domid = DOMID_SELF 83 }; 84 unsigned long start, end; 85 unsigned long len = 0; 86 unsigned long pfn; 87 int ret; 88 89 start = PFN_UP(start_addr); 90 end = PFN_DOWN(end_addr); 91 92 if (end <= start) 93 return 0; 94 95 printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ", 96 start, end); 97 for(pfn = start; pfn < end; pfn++) { 98 unsigned long mfn = pfn_to_mfn(pfn); 99 100 /* Make sure pfn exists to start with */ 101 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn) 102 continue; 103 104 set_xen_guest_handle(reservation.extent_start, &mfn); 105 reservation.nr_extents = 1; 106 107 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, 108 &reservation); 109 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n", 110 start, end, ret); 111 if (ret == 1) { 112 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 113 len++; 114 } 115 } 116 printk(KERN_CONT "%ld pages freed\n", len); 117 118 return len; 119 } 120 121 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn, 122 const struct e820map *e820) 123 { 124 phys_addr_t max_addr = PFN_PHYS(max_pfn); 125 phys_addr_t last_end = ISA_END_ADDRESS; 126 unsigned long released = 0; 127 int i; 128 129 /* Free any unused memory above the low 1Mbyte. */ 130 for (i = 0; i < e820->nr_map && last_end < max_addr; i++) { 131 phys_addr_t end = e820->map[i].addr; 132 end = min(max_addr, end); 133 134 if (last_end < end) 135 released += xen_release_chunk(last_end, end); 136 last_end = max(last_end, e820->map[i].addr + e820->map[i].size); 137 } 138 139 if (last_end < max_addr) 140 released += xen_release_chunk(last_end, max_addr); 141 142 printk(KERN_INFO "released %ld pages of unused memory\n", released); 143 return released; 144 } 145 146 static unsigned long __init xen_set_identity(const struct e820entry *list, 147 ssize_t map_size) 148 { 149 phys_addr_t last = xen_initial_domain() ? 0 : ISA_END_ADDRESS; 150 phys_addr_t start_pci = last; 151 const struct e820entry *entry; 152 unsigned long identity = 0; 153 int i; 154 155 for (i = 0, entry = list; i < map_size; i++, entry++) { 156 phys_addr_t start = entry->addr; 157 phys_addr_t end = start + entry->size; 158 159 if (start < last) 160 start = last; 161 162 if (end <= start) 163 continue; 164 165 /* Skip over the 1MB region. */ 166 if (last > end) 167 continue; 168 169 if ((entry->type == E820_RAM) || (entry->type == E820_UNUSABLE)) { 170 if (start > start_pci) 171 identity += set_phys_range_identity( 172 PFN_UP(start_pci), PFN_DOWN(start)); 173 174 /* Without saving 'last' we would gooble RAM too 175 * at the end of the loop. */ 176 last = end; 177 start_pci = end; 178 continue; 179 } 180 start_pci = min(start, start_pci); 181 last = end; 182 } 183 if (last > start_pci) 184 identity += set_phys_range_identity( 185 PFN_UP(start_pci), PFN_DOWN(last)); 186 return identity; 187 } 188 /** 189 * machine_specific_memory_setup - Hook for machine specific memory setup. 190 **/ 191 char * __init xen_memory_setup(void) 192 { 193 static struct e820entry map[E820MAX] __initdata; 194 static struct e820entry map_raw[E820MAX] __initdata; 195 196 unsigned long max_pfn = xen_start_info->nr_pages; 197 unsigned long long mem_end; 198 int rc; 199 struct xen_memory_map memmap; 200 unsigned long extra_pages = 0; 201 unsigned long extra_limit; 202 unsigned long identity_pages = 0; 203 int i; 204 int op; 205 206 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); 207 mem_end = PFN_PHYS(max_pfn); 208 209 memmap.nr_entries = E820MAX; 210 set_xen_guest_handle(memmap.buffer, map); 211 212 op = xen_initial_domain() ? 213 XENMEM_machine_memory_map : 214 XENMEM_memory_map; 215 rc = HYPERVISOR_memory_op(op, &memmap); 216 if (rc == -ENOSYS) { 217 BUG_ON(xen_initial_domain()); 218 memmap.nr_entries = 1; 219 map[0].addr = 0ULL; 220 map[0].size = mem_end; 221 /* 8MB slack (to balance backend allocations). */ 222 map[0].size += 8ULL << 20; 223 map[0].type = E820_RAM; 224 rc = 0; 225 } 226 BUG_ON(rc); 227 228 memcpy(map_raw, map, sizeof(map)); 229 e820.nr_map = 0; 230 xen_extra_mem_start = mem_end; 231 for (i = 0; i < memmap.nr_entries; i++) { 232 unsigned long long end; 233 234 /* Guard against non-page aligned E820 entries. */ 235 if (map[i].type == E820_RAM) 236 map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE; 237 238 end = map[i].addr + map[i].size; 239 if (map[i].type == E820_RAM && end > mem_end) { 240 /* RAM off the end - may be partially included */ 241 u64 delta = min(map[i].size, end - mem_end); 242 243 map[i].size -= delta; 244 end -= delta; 245 246 extra_pages += PFN_DOWN(delta); 247 /* 248 * Set RAM below 4GB that is not for us to be unusable. 249 * This prevents "System RAM" address space from being 250 * used as potential resource for I/O address (happens 251 * when 'allocate_resource' is called). 252 */ 253 if (delta && 254 (xen_initial_domain() && end < 0x100000000ULL)) 255 e820_add_region(end, delta, E820_UNUSABLE); 256 } 257 258 if (map[i].size > 0 && end > xen_extra_mem_start) 259 xen_extra_mem_start = end; 260 261 /* Add region if any remains */ 262 if (map[i].size > 0) 263 e820_add_region(map[i].addr, map[i].size, map[i].type); 264 } 265 /* Align the balloon area so that max_low_pfn does not get set 266 * to be at the _end_ of the PCI gap at the far end (fee01000). 267 * Note that xen_extra_mem_start gets set in the loop above to be 268 * past the last E820 region. */ 269 if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32))) 270 xen_extra_mem_start = (1ULL<<32); 271 272 /* 273 * In domU, the ISA region is normal, usable memory, but we 274 * reserve ISA memory anyway because too many things poke 275 * about in there. 276 * 277 * In Dom0, the host E820 information can leave gaps in the 278 * ISA range, which would cause us to release those pages. To 279 * avoid this, we unconditionally reserve them here. 280 */ 281 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, 282 E820_RESERVED); 283 284 /* 285 * Reserve Xen bits: 286 * - mfn_list 287 * - xen_start_info 288 * See comment above "struct start_info" in <xen/interface/xen.h> 289 */ 290 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list), 291 __pa(xen_start_info->pt_base), 292 "XEN START INFO"); 293 294 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 295 296 extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820); 297 298 /* 299 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO 300 * factor the base size. On non-highmem systems, the base 301 * size is the full initial memory allocation; on highmem it 302 * is limited to the max size of lowmem, so that it doesn't 303 * get completely filled. 304 * 305 * In principle there could be a problem in lowmem systems if 306 * the initial memory is also very large with respect to 307 * lowmem, but we won't try to deal with that here. 308 */ 309 extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), 310 max_pfn + extra_pages); 311 312 if (extra_limit >= max_pfn) 313 extra_pages = extra_limit - max_pfn; 314 else 315 extra_pages = 0; 316 317 xen_add_extra_mem(extra_pages); 318 319 /* 320 * Set P2M for all non-RAM pages and E820 gaps to be identity 321 * type PFNs. We supply it with the non-sanitized version 322 * of the E820. 323 */ 324 identity_pages = xen_set_identity(map_raw, memmap.nr_entries); 325 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages); 326 return "Xen"; 327 } 328 329 /* 330 * Set the bit indicating "nosegneg" library variants should be used. 331 * We only need to bother in pure 32-bit mode; compat 32-bit processes 332 * can have un-truncated segments, so wrapping around is allowed. 333 */ 334 static void __init fiddle_vdso(void) 335 { 336 #ifdef CONFIG_X86_32 337 u32 *mask; 338 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); 339 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 340 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); 341 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 342 #endif 343 } 344 345 static int __cpuinit register_callback(unsigned type, const void *func) 346 { 347 struct callback_register callback = { 348 .type = type, 349 .address = XEN_CALLBACK(__KERNEL_CS, func), 350 .flags = CALLBACKF_mask_events, 351 }; 352 353 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback); 354 } 355 356 void __cpuinit xen_enable_sysenter(void) 357 { 358 int ret; 359 unsigned sysenter_feature; 360 361 #ifdef CONFIG_X86_32 362 sysenter_feature = X86_FEATURE_SEP; 363 #else 364 sysenter_feature = X86_FEATURE_SYSENTER32; 365 #endif 366 367 if (!boot_cpu_has(sysenter_feature)) 368 return; 369 370 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target); 371 if(ret != 0) 372 setup_clear_cpu_cap(sysenter_feature); 373 } 374 375 void __cpuinit xen_enable_syscall(void) 376 { 377 #ifdef CONFIG_X86_64 378 int ret; 379 380 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target); 381 if (ret != 0) { 382 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret); 383 /* Pretty fatal; 64-bit userspace has no other 384 mechanism for syscalls. */ 385 } 386 387 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) { 388 ret = register_callback(CALLBACKTYPE_syscall32, 389 xen_syscall32_target); 390 if (ret != 0) 391 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); 392 } 393 #endif /* CONFIG_X86_64 */ 394 } 395 396 void __init xen_arch_setup(void) 397 { 398 xen_panic_handler_init(); 399 400 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); 401 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); 402 403 if (!xen_feature(XENFEAT_auto_translated_physmap)) 404 HYPERVISOR_vm_assist(VMASST_CMD_enable, 405 VMASST_TYPE_pae_extended_cr3); 406 407 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) || 408 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback)) 409 BUG(); 410 411 xen_enable_sysenter(); 412 xen_enable_syscall(); 413 414 #ifdef CONFIG_ACPI 415 if (!(xen_start_info->flags & SIF_INITDOMAIN)) { 416 printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); 417 disable_acpi(); 418 } 419 #endif 420 421 memcpy(boot_command_line, xen_start_info->cmd_line, 422 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? 423 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); 424 425 /* Set up idle, making sure it calls safe_halt() pvop */ 426 #ifdef CONFIG_X86_32 427 boot_cpu_data.hlt_works_ok = 1; 428 #endif 429 pm_idle = default_idle; 430 boot_option_idle_override = IDLE_HALT; 431 432 fiddle_vdso(); 433 } 434