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 #include <linux/cpuidle.h> 13 14 #include <asm/elf.h> 15 #include <asm/vdso.h> 16 #include <asm/e820.h> 17 #include <asm/setup.h> 18 #include <asm/acpi.h> 19 #include <asm/xen/hypervisor.h> 20 #include <asm/xen/hypercall.h> 21 22 #include <xen/xen.h> 23 #include <xen/page.h> 24 #include <xen/interface/callback.h> 25 #include <xen/interface/memory.h> 26 #include <xen/interface/physdev.h> 27 #include <xen/features.h> 28 29 #include "xen-ops.h" 30 #include "vdso.h" 31 32 /* These are code, but not functions. Defined in entry.S */ 33 extern const char xen_hypervisor_callback[]; 34 extern const char xen_failsafe_callback[]; 35 extern void xen_sysenter_target(void); 36 extern void xen_syscall_target(void); 37 extern void xen_syscall32_target(void); 38 39 /* Amount of extra memory space we add to the e820 ranges */ 40 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; 41 42 /* Number of pages released from the initial allocation. */ 43 unsigned long xen_released_pages; 44 45 /* 46 * The maximum amount of extra memory compared to the base size. The 47 * main scaling factor is the size of struct page. At extreme ratios 48 * of base:extra, all the base memory can be filled with page 49 * structures for the extra memory, leaving no space for anything 50 * else. 51 * 52 * 10x seems like a reasonable balance between scaling flexibility and 53 * leaving a practically usable system. 54 */ 55 #define EXTRA_MEM_RATIO (10) 56 57 static void __init xen_add_extra_mem(u64 start, u64 size) 58 { 59 unsigned long pfn; 60 int i; 61 62 for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) { 63 /* Add new region. */ 64 if (xen_extra_mem[i].size == 0) { 65 xen_extra_mem[i].start = start; 66 xen_extra_mem[i].size = size; 67 break; 68 } 69 /* Append to existing region. */ 70 if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) { 71 xen_extra_mem[i].size += size; 72 break; 73 } 74 } 75 if (i == XEN_EXTRA_MEM_MAX_REGIONS) 76 printk(KERN_WARNING "Warning: not enough extra memory regions\n"); 77 78 memblock_reserve(start, size); 79 80 xen_max_p2m_pfn = PFN_DOWN(start + size); 81 82 for (pfn = PFN_DOWN(start); pfn <= xen_max_p2m_pfn; pfn++) 83 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 84 } 85 86 static unsigned long __init xen_release_chunk(unsigned long start, 87 unsigned long end) 88 { 89 struct xen_memory_reservation reservation = { 90 .address_bits = 0, 91 .extent_order = 0, 92 .domid = DOMID_SELF 93 }; 94 unsigned long len = 0; 95 unsigned long pfn; 96 int ret; 97 98 for(pfn = start; pfn < end; pfn++) { 99 unsigned long mfn = pfn_to_mfn(pfn); 100 101 /* Make sure pfn exists to start with */ 102 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn) 103 continue; 104 105 set_xen_guest_handle(reservation.extent_start, &mfn); 106 reservation.nr_extents = 1; 107 108 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, 109 &reservation); 110 WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret); 111 if (ret == 1) { 112 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 113 len++; 114 } 115 } 116 printk(KERN_INFO "Freeing %lx-%lx pfn range: %lu pages freed\n", 117 start, end, len); 118 119 return len; 120 } 121 122 static unsigned long __init xen_set_identity_and_release( 123 const struct e820entry *list, size_t map_size, unsigned long nr_pages) 124 { 125 phys_addr_t start = 0; 126 unsigned long released = 0; 127 unsigned long identity = 0; 128 const struct e820entry *entry; 129 int i; 130 131 /* 132 * Combine non-RAM regions and gaps until a RAM region (or the 133 * end of the map) is reached, then set the 1:1 map and 134 * release the pages (if available) in those non-RAM regions. 135 * 136 * The combined non-RAM regions are rounded to a whole number 137 * of pages so any partial pages are accessible via the 1:1 138 * mapping. This is needed for some BIOSes that put (for 139 * example) the DMI tables in a reserved region that begins on 140 * a non-page boundary. 141 */ 142 for (i = 0, entry = list; i < map_size; i++, entry++) { 143 phys_addr_t end = entry->addr + entry->size; 144 145 if (entry->type == E820_RAM || i == map_size - 1) { 146 unsigned long start_pfn = PFN_DOWN(start); 147 unsigned long end_pfn = PFN_UP(end); 148 149 if (entry->type == E820_RAM) 150 end_pfn = PFN_UP(entry->addr); 151 152 if (start_pfn < end_pfn) { 153 if (start_pfn < nr_pages) 154 released += xen_release_chunk( 155 start_pfn, min(end_pfn, nr_pages)); 156 157 identity += set_phys_range_identity( 158 start_pfn, end_pfn); 159 } 160 start = end; 161 } 162 } 163 164 printk(KERN_INFO "Released %lu pages of unused memory\n", released); 165 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping\n", identity); 166 167 return released; 168 } 169 170 static unsigned long __init xen_get_max_pages(void) 171 { 172 unsigned long max_pages = MAX_DOMAIN_PAGES; 173 domid_t domid = DOMID_SELF; 174 int ret; 175 176 /* 177 * For the initial domain we use the maximum reservation as 178 * the maximum page. 179 * 180 * For guest domains the current maximum reservation reflects 181 * the current maximum rather than the static maximum. In this 182 * case the e820 map provided to us will cover the static 183 * maximum region. 184 */ 185 if (xen_initial_domain()) { 186 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid); 187 if (ret > 0) 188 max_pages = ret; 189 } 190 191 return min(max_pages, MAX_DOMAIN_PAGES); 192 } 193 194 static void xen_align_and_add_e820_region(u64 start, u64 size, int type) 195 { 196 u64 end = start + size; 197 198 /* Align RAM regions to page boundaries. */ 199 if (type == E820_RAM) { 200 start = PAGE_ALIGN(start); 201 end &= ~((u64)PAGE_SIZE - 1); 202 } 203 204 e820_add_region(start, end - start, type); 205 } 206 207 /** 208 * machine_specific_memory_setup - Hook for machine specific memory setup. 209 **/ 210 char * __init xen_memory_setup(void) 211 { 212 static struct e820entry map[E820MAX] __initdata; 213 214 unsigned long max_pfn = xen_start_info->nr_pages; 215 unsigned long long mem_end; 216 int rc; 217 struct xen_memory_map memmap; 218 unsigned long max_pages; 219 unsigned long extra_pages = 0; 220 int i; 221 int op; 222 223 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); 224 mem_end = PFN_PHYS(max_pfn); 225 226 memmap.nr_entries = E820MAX; 227 set_xen_guest_handle(memmap.buffer, map); 228 229 op = xen_initial_domain() ? 230 XENMEM_machine_memory_map : 231 XENMEM_memory_map; 232 rc = HYPERVISOR_memory_op(op, &memmap); 233 if (rc == -ENOSYS) { 234 BUG_ON(xen_initial_domain()); 235 memmap.nr_entries = 1; 236 map[0].addr = 0ULL; 237 map[0].size = mem_end; 238 /* 8MB slack (to balance backend allocations). */ 239 map[0].size += 8ULL << 20; 240 map[0].type = E820_RAM; 241 rc = 0; 242 } 243 BUG_ON(rc); 244 245 /* Make sure the Xen-supplied memory map is well-ordered. */ 246 sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries); 247 248 max_pages = xen_get_max_pages(); 249 if (max_pages > max_pfn) 250 extra_pages += max_pages - max_pfn; 251 252 /* 253 * Set P2M for all non-RAM pages and E820 gaps to be identity 254 * type PFNs. Any RAM pages that would be made inaccesible by 255 * this are first released. 256 */ 257 xen_released_pages = xen_set_identity_and_release( 258 map, memmap.nr_entries, max_pfn); 259 extra_pages += xen_released_pages; 260 261 /* 262 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO 263 * factor the base size. On non-highmem systems, the base 264 * size is the full initial memory allocation; on highmem it 265 * is limited to the max size of lowmem, so that it doesn't 266 * get completely filled. 267 * 268 * In principle there could be a problem in lowmem systems if 269 * the initial memory is also very large with respect to 270 * lowmem, but we won't try to deal with that here. 271 */ 272 extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), 273 extra_pages); 274 275 i = 0; 276 while (i < memmap.nr_entries) { 277 u64 addr = map[i].addr; 278 u64 size = map[i].size; 279 u32 type = map[i].type; 280 281 if (type == E820_RAM) { 282 if (addr < mem_end) { 283 size = min(size, mem_end - addr); 284 } else if (extra_pages) { 285 size = min(size, (u64)extra_pages * PAGE_SIZE); 286 extra_pages -= size / PAGE_SIZE; 287 xen_add_extra_mem(addr, size); 288 } else 289 type = E820_UNUSABLE; 290 } 291 292 xen_align_and_add_e820_region(addr, size, type); 293 294 map[i].addr += size; 295 map[i].size -= size; 296 if (map[i].size == 0) 297 i++; 298 } 299 300 /* 301 * In domU, the ISA region is normal, usable memory, but we 302 * reserve ISA memory anyway because too many things poke 303 * about in there. 304 */ 305 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, 306 E820_RESERVED); 307 308 /* 309 * Reserve Xen bits: 310 * - mfn_list 311 * - xen_start_info 312 * See comment above "struct start_info" in <xen/interface/xen.h> 313 */ 314 memblock_reserve(__pa(xen_start_info->mfn_list), 315 xen_start_info->pt_base - xen_start_info->mfn_list); 316 317 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 318 319 return "Xen"; 320 } 321 322 /* 323 * Set the bit indicating "nosegneg" library variants should be used. 324 * We only need to bother in pure 32-bit mode; compat 32-bit processes 325 * can have un-truncated segments, so wrapping around is allowed. 326 */ 327 static void __init fiddle_vdso(void) 328 { 329 #ifdef CONFIG_X86_32 330 u32 *mask; 331 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); 332 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 333 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); 334 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 335 #endif 336 } 337 338 static int __cpuinit register_callback(unsigned type, const void *func) 339 { 340 struct callback_register callback = { 341 .type = type, 342 .address = XEN_CALLBACK(__KERNEL_CS, func), 343 .flags = CALLBACKF_mask_events, 344 }; 345 346 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback); 347 } 348 349 void __cpuinit xen_enable_sysenter(void) 350 { 351 int ret; 352 unsigned sysenter_feature; 353 354 #ifdef CONFIG_X86_32 355 sysenter_feature = X86_FEATURE_SEP; 356 #else 357 sysenter_feature = X86_FEATURE_SYSENTER32; 358 #endif 359 360 if (!boot_cpu_has(sysenter_feature)) 361 return; 362 363 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target); 364 if(ret != 0) 365 setup_clear_cpu_cap(sysenter_feature); 366 } 367 368 void __cpuinit xen_enable_syscall(void) 369 { 370 #ifdef CONFIG_X86_64 371 int ret; 372 373 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target); 374 if (ret != 0) { 375 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret); 376 /* Pretty fatal; 64-bit userspace has no other 377 mechanism for syscalls. */ 378 } 379 380 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) { 381 ret = register_callback(CALLBACKTYPE_syscall32, 382 xen_syscall32_target); 383 if (ret != 0) 384 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); 385 } 386 #endif /* CONFIG_X86_64 */ 387 } 388 389 void __init xen_arch_setup(void) 390 { 391 xen_panic_handler_init(); 392 393 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); 394 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); 395 396 if (!xen_feature(XENFEAT_auto_translated_physmap)) 397 HYPERVISOR_vm_assist(VMASST_CMD_enable, 398 VMASST_TYPE_pae_extended_cr3); 399 400 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) || 401 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback)) 402 BUG(); 403 404 xen_enable_sysenter(); 405 xen_enable_syscall(); 406 407 #ifdef CONFIG_ACPI 408 if (!(xen_start_info->flags & SIF_INITDOMAIN)) { 409 printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); 410 disable_acpi(); 411 } 412 #endif 413 414 memcpy(boot_command_line, xen_start_info->cmd_line, 415 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? 416 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); 417 418 /* Set up idle, making sure it calls safe_halt() pvop */ 419 #ifdef CONFIG_X86_32 420 boot_cpu_data.hlt_works_ok = 1; 421 #endif 422 disable_cpuidle(); 423 boot_option_idle_override = IDLE_HALT; 424 WARN_ON(set_pm_idle_to_default()); 425 fiddle_vdso(); 426 } 427