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_x86_reserve_range(start, start + size, "XEN EXTRA"); 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 ret = HYPERVISOR_memory_op(XENMEM_maximum_reservation, &domid); 177 if (ret > 0) 178 max_pages = ret; 179 return min(max_pages, MAX_DOMAIN_PAGES); 180 } 181 182 static void xen_align_and_add_e820_region(u64 start, u64 size, int type) 183 { 184 u64 end = start + size; 185 186 /* Align RAM regions to page boundaries. */ 187 if (type == E820_RAM) { 188 start = PAGE_ALIGN(start); 189 end &= ~((u64)PAGE_SIZE - 1); 190 } 191 192 e820_add_region(start, end - start, type); 193 } 194 195 /** 196 * machine_specific_memory_setup - Hook for machine specific memory setup. 197 **/ 198 char * __init xen_memory_setup(void) 199 { 200 static struct e820entry map[E820MAX] __initdata; 201 202 unsigned long max_pfn = xen_start_info->nr_pages; 203 unsigned long long mem_end; 204 int rc; 205 struct xen_memory_map memmap; 206 unsigned long max_pages; 207 unsigned long extra_pages = 0; 208 int i; 209 int op; 210 211 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); 212 mem_end = PFN_PHYS(max_pfn); 213 214 memmap.nr_entries = E820MAX; 215 set_xen_guest_handle(memmap.buffer, map); 216 217 op = xen_initial_domain() ? 218 XENMEM_machine_memory_map : 219 XENMEM_memory_map; 220 rc = HYPERVISOR_memory_op(op, &memmap); 221 if (rc == -ENOSYS) { 222 BUG_ON(xen_initial_domain()); 223 memmap.nr_entries = 1; 224 map[0].addr = 0ULL; 225 map[0].size = mem_end; 226 /* 8MB slack (to balance backend allocations). */ 227 map[0].size += 8ULL << 20; 228 map[0].type = E820_RAM; 229 rc = 0; 230 } 231 BUG_ON(rc); 232 233 /* Make sure the Xen-supplied memory map is well-ordered. */ 234 sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries); 235 236 max_pages = xen_get_max_pages(); 237 if (max_pages > max_pfn) 238 extra_pages += max_pages - max_pfn; 239 240 /* 241 * Set P2M for all non-RAM pages and E820 gaps to be identity 242 * type PFNs. Any RAM pages that would be made inaccesible by 243 * this are first released. 244 */ 245 xen_released_pages = xen_set_identity_and_release( 246 map, memmap.nr_entries, max_pfn); 247 extra_pages += xen_released_pages; 248 249 /* 250 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO 251 * factor the base size. On non-highmem systems, the base 252 * size is the full initial memory allocation; on highmem it 253 * is limited to the max size of lowmem, so that it doesn't 254 * get completely filled. 255 * 256 * In principle there could be a problem in lowmem systems if 257 * the initial memory is also very large with respect to 258 * lowmem, but we won't try to deal with that here. 259 */ 260 extra_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), 261 extra_pages); 262 263 i = 0; 264 while (i < memmap.nr_entries) { 265 u64 addr = map[i].addr; 266 u64 size = map[i].size; 267 u32 type = map[i].type; 268 269 if (type == E820_RAM) { 270 if (addr < mem_end) { 271 size = min(size, mem_end - addr); 272 } else if (extra_pages) { 273 size = min(size, (u64)extra_pages * PAGE_SIZE); 274 extra_pages -= size / PAGE_SIZE; 275 xen_add_extra_mem(addr, size); 276 } else 277 type = E820_UNUSABLE; 278 } 279 280 xen_align_and_add_e820_region(addr, size, type); 281 282 map[i].addr += size; 283 map[i].size -= size; 284 if (map[i].size == 0) 285 i++; 286 } 287 288 /* 289 * In domU, the ISA region is normal, usable memory, but we 290 * reserve ISA memory anyway because too many things poke 291 * about in there. 292 */ 293 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, 294 E820_RESERVED); 295 296 /* 297 * Reserve Xen bits: 298 * - mfn_list 299 * - xen_start_info 300 * See comment above "struct start_info" in <xen/interface/xen.h> 301 */ 302 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list), 303 __pa(xen_start_info->pt_base), 304 "XEN START INFO"); 305 306 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 307 308 return "Xen"; 309 } 310 311 /* 312 * Set the bit indicating "nosegneg" library variants should be used. 313 * We only need to bother in pure 32-bit mode; compat 32-bit processes 314 * can have un-truncated segments, so wrapping around is allowed. 315 */ 316 static void __init fiddle_vdso(void) 317 { 318 #ifdef CONFIG_X86_32 319 u32 *mask; 320 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); 321 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 322 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); 323 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 324 #endif 325 } 326 327 static int __cpuinit register_callback(unsigned type, const void *func) 328 { 329 struct callback_register callback = { 330 .type = type, 331 .address = XEN_CALLBACK(__KERNEL_CS, func), 332 .flags = CALLBACKF_mask_events, 333 }; 334 335 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback); 336 } 337 338 void __cpuinit xen_enable_sysenter(void) 339 { 340 int ret; 341 unsigned sysenter_feature; 342 343 #ifdef CONFIG_X86_32 344 sysenter_feature = X86_FEATURE_SEP; 345 #else 346 sysenter_feature = X86_FEATURE_SYSENTER32; 347 #endif 348 349 if (!boot_cpu_has(sysenter_feature)) 350 return; 351 352 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target); 353 if(ret != 0) 354 setup_clear_cpu_cap(sysenter_feature); 355 } 356 357 void __cpuinit xen_enable_syscall(void) 358 { 359 #ifdef CONFIG_X86_64 360 int ret; 361 362 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target); 363 if (ret != 0) { 364 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret); 365 /* Pretty fatal; 64-bit userspace has no other 366 mechanism for syscalls. */ 367 } 368 369 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) { 370 ret = register_callback(CALLBACKTYPE_syscall32, 371 xen_syscall32_target); 372 if (ret != 0) 373 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); 374 } 375 #endif /* CONFIG_X86_64 */ 376 } 377 378 void __init xen_arch_setup(void) 379 { 380 xen_panic_handler_init(); 381 382 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); 383 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); 384 385 if (!xen_feature(XENFEAT_auto_translated_physmap)) 386 HYPERVISOR_vm_assist(VMASST_CMD_enable, 387 VMASST_TYPE_pae_extended_cr3); 388 389 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) || 390 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback)) 391 BUG(); 392 393 xen_enable_sysenter(); 394 xen_enable_syscall(); 395 396 #ifdef CONFIG_ACPI 397 if (!(xen_start_info->flags & SIF_INITDOMAIN)) { 398 printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); 399 disable_acpi(); 400 } 401 #endif 402 403 memcpy(boot_command_line, xen_start_info->cmd_line, 404 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? 405 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); 406 407 /* Set up idle, making sure it calls safe_halt() pvop */ 408 #ifdef CONFIG_X86_32 409 boot_cpu_data.hlt_works_ok = 1; 410 #endif 411 disable_cpuidle(); 412 boot_option_idle_override = IDLE_HALT; 413 414 fiddle_vdso(); 415 } 416