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 __init void xen_add_extra_mem(unsigned long pages) 54 { 55 u64 size = (u64)pages * PAGE_SIZE; 56 u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; 57 58 if (!pages) 59 return; 60 61 e820_add_region(extra_start, size, E820_RAM); 62 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 63 64 memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA"); 65 66 xen_extra_mem_size += size; 67 68 xen_max_p2m_pfn = PFN_DOWN(extra_start + size); 69 } 70 71 static unsigned long __init xen_release_chunk(phys_addr_t start_addr, 72 phys_addr_t end_addr) 73 { 74 struct xen_memory_reservation reservation = { 75 .address_bits = 0, 76 .extent_order = 0, 77 .domid = DOMID_SELF 78 }; 79 unsigned long start, end; 80 unsigned long len = 0; 81 unsigned long pfn; 82 int ret; 83 84 start = PFN_UP(start_addr); 85 end = PFN_DOWN(end_addr); 86 87 if (end <= start) 88 return 0; 89 90 printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ", 91 start, end); 92 for(pfn = start; pfn < end; pfn++) { 93 unsigned long mfn = pfn_to_mfn(pfn); 94 95 /* Make sure pfn exists to start with */ 96 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn) 97 continue; 98 99 set_xen_guest_handle(reservation.extent_start, &mfn); 100 reservation.nr_extents = 1; 101 102 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation, 103 &reservation); 104 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n", 105 start, end, ret); 106 if (ret == 1) { 107 set_phys_to_machine(pfn, INVALID_P2M_ENTRY); 108 len++; 109 } 110 } 111 printk(KERN_CONT "%ld pages freed\n", len); 112 113 return len; 114 } 115 116 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn, 117 const struct e820map *e820) 118 { 119 phys_addr_t max_addr = PFN_PHYS(max_pfn); 120 phys_addr_t last_end = ISA_END_ADDRESS; 121 unsigned long released = 0; 122 int i; 123 124 /* Free any unused memory above the low 1Mbyte. */ 125 for (i = 0; i < e820->nr_map && last_end < max_addr; i++) { 126 phys_addr_t end = e820->map[i].addr; 127 end = min(max_addr, end); 128 129 if (last_end < end) 130 released += xen_release_chunk(last_end, end); 131 last_end = max(last_end, e820->map[i].addr + e820->map[i].size); 132 } 133 134 if (last_end < max_addr) 135 released += xen_release_chunk(last_end, max_addr); 136 137 printk(KERN_INFO "released %ld pages of unused memory\n", released); 138 return released; 139 } 140 141 /** 142 * machine_specific_memory_setup - Hook for machine specific memory setup. 143 **/ 144 char * __init xen_memory_setup(void) 145 { 146 static struct e820entry map[E820MAX] __initdata; 147 148 unsigned long max_pfn = xen_start_info->nr_pages; 149 unsigned long long mem_end; 150 int rc; 151 struct xen_memory_map memmap; 152 unsigned long extra_pages = 0; 153 unsigned long extra_limit; 154 int i; 155 int op; 156 157 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn); 158 mem_end = PFN_PHYS(max_pfn); 159 160 memmap.nr_entries = E820MAX; 161 set_xen_guest_handle(memmap.buffer, map); 162 163 op = xen_initial_domain() ? 164 XENMEM_machine_memory_map : 165 XENMEM_memory_map; 166 rc = HYPERVISOR_memory_op(op, &memmap); 167 if (rc == -ENOSYS) { 168 BUG_ON(xen_initial_domain()); 169 memmap.nr_entries = 1; 170 map[0].addr = 0ULL; 171 map[0].size = mem_end; 172 /* 8MB slack (to balance backend allocations). */ 173 map[0].size += 8ULL << 20; 174 map[0].type = E820_RAM; 175 rc = 0; 176 } 177 BUG_ON(rc); 178 179 e820.nr_map = 0; 180 xen_extra_mem_start = mem_end; 181 for (i = 0; i < memmap.nr_entries; i++) { 182 unsigned long long end = map[i].addr + map[i].size; 183 184 if (map[i].type == E820_RAM && end > mem_end) { 185 /* RAM off the end - may be partially included */ 186 u64 delta = min(map[i].size, end - mem_end); 187 188 map[i].size -= delta; 189 end -= delta; 190 191 extra_pages += PFN_DOWN(delta); 192 } 193 194 if (map[i].size > 0 && end > xen_extra_mem_start) 195 xen_extra_mem_start = end; 196 197 /* Add region if any remains */ 198 if (map[i].size > 0) 199 e820_add_region(map[i].addr, map[i].size, map[i].type); 200 } 201 202 /* 203 * In domU, the ISA region is normal, usable memory, but we 204 * reserve ISA memory anyway because too many things poke 205 * about in there. 206 * 207 * In Dom0, the host E820 information can leave gaps in the 208 * ISA range, which would cause us to release those pages. To 209 * avoid this, we unconditionally reserve them here. 210 */ 211 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS, 212 E820_RESERVED); 213 214 /* 215 * Reserve Xen bits: 216 * - mfn_list 217 * - xen_start_info 218 * See comment above "struct start_info" in <xen/interface/xen.h> 219 */ 220 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list), 221 __pa(xen_start_info->pt_base), 222 "XEN START INFO"); 223 224 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); 225 226 extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820); 227 228 /* 229 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO 230 * factor the base size. On non-highmem systems, the base 231 * size is the full initial memory allocation; on highmem it 232 * is limited to the max size of lowmem, so that it doesn't 233 * get completely filled. 234 * 235 * In principle there could be a problem in lowmem systems if 236 * the initial memory is also very large with respect to 237 * lowmem, but we won't try to deal with that here. 238 */ 239 extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)), 240 max_pfn + extra_pages); 241 242 if (extra_limit >= max_pfn) 243 extra_pages = extra_limit - max_pfn; 244 else 245 extra_pages = 0; 246 247 xen_add_extra_mem(extra_pages); 248 249 return "Xen"; 250 } 251 252 /* 253 * Set the bit indicating "nosegneg" library variants should be used. 254 * We only need to bother in pure 32-bit mode; compat 32-bit processes 255 * can have un-truncated segments, so wrapping around is allowed. 256 */ 257 static void __init fiddle_vdso(void) 258 { 259 #ifdef CONFIG_X86_32 260 u32 *mask; 261 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK); 262 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 263 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK); 264 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT; 265 #endif 266 } 267 268 static __cpuinit int register_callback(unsigned type, const void *func) 269 { 270 struct callback_register callback = { 271 .type = type, 272 .address = XEN_CALLBACK(__KERNEL_CS, func), 273 .flags = CALLBACKF_mask_events, 274 }; 275 276 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback); 277 } 278 279 void __cpuinit xen_enable_sysenter(void) 280 { 281 int ret; 282 unsigned sysenter_feature; 283 284 #ifdef CONFIG_X86_32 285 sysenter_feature = X86_FEATURE_SEP; 286 #else 287 sysenter_feature = X86_FEATURE_SYSENTER32; 288 #endif 289 290 if (!boot_cpu_has(sysenter_feature)) 291 return; 292 293 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target); 294 if(ret != 0) 295 setup_clear_cpu_cap(sysenter_feature); 296 } 297 298 void __cpuinit xen_enable_syscall(void) 299 { 300 #ifdef CONFIG_X86_64 301 int ret; 302 303 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target); 304 if (ret != 0) { 305 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret); 306 /* Pretty fatal; 64-bit userspace has no other 307 mechanism for syscalls. */ 308 } 309 310 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) { 311 ret = register_callback(CALLBACKTYPE_syscall32, 312 xen_syscall32_target); 313 if (ret != 0) 314 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32); 315 } 316 #endif /* CONFIG_X86_64 */ 317 } 318 319 void __init xen_arch_setup(void) 320 { 321 xen_panic_handler_init(); 322 323 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments); 324 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables); 325 326 if (!xen_feature(XENFEAT_auto_translated_physmap)) 327 HYPERVISOR_vm_assist(VMASST_CMD_enable, 328 VMASST_TYPE_pae_extended_cr3); 329 330 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) || 331 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback)) 332 BUG(); 333 334 xen_enable_sysenter(); 335 xen_enable_syscall(); 336 337 #ifdef CONFIG_ACPI 338 if (!(xen_start_info->flags & SIF_INITDOMAIN)) { 339 printk(KERN_INFO "ACPI in unprivileged domain disabled\n"); 340 disable_acpi(); 341 } 342 #endif 343 344 memcpy(boot_command_line, xen_start_info->cmd_line, 345 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ? 346 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE); 347 348 /* Set up idle, making sure it calls safe_halt() pvop */ 349 #ifdef CONFIG_X86_32 350 boot_cpu_data.hlt_works_ok = 1; 351 #endif 352 pm_idle = default_idle; 353 354 fiddle_vdso(); 355 } 356