2 * Machine specific setup for xen
4 * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
7 #include <linux/module.h>
8 #include <linux/sched.h>
11 #include <linux/memblock.h>
16 #include <asm/setup.h>
18 #include <asm/xen/hypervisor.h>
19 #include <asm/xen/hypercall.h>
23 #include <xen/interface/callback.h>
24 #include <xen/interface/memory.h>
25 #include <xen/interface/physdev.h>
26 #include <xen/features.h>
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);
38 /* Amount of extra memory space we add to the e820 ranges */
39 phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
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
48 * 10x seems like a reasonable balance between scaling flexibility and
49 * leaving a practically usable system.
51 #define EXTRA_MEM_RATIO (10)
53 static __init void xen_add_extra_mem(unsigned long pages)
57 u64 size = (u64)pages * PAGE_SIZE;
58 u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
63 e820_add_region(extra_start, size, E820_RAM);
64 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
66 memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
68 xen_extra_mem_size += size;
70 xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
72 for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++)
73 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
76 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
79 struct xen_memory_reservation reservation = {
84 unsigned long start, end;
85 unsigned long len = 0;
89 start = PFN_UP(start_addr);
90 end = PFN_DOWN(end_addr);
95 printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
97 for(pfn = start; pfn < end; pfn++) {
98 unsigned long mfn = pfn_to_mfn(pfn);
100 /* Make sure pfn exists to start with */
101 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
104 set_xen_guest_handle(reservation.extent_start, &mfn);
105 reservation.nr_extents = 1;
107 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
109 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
112 __set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
116 printk(KERN_CONT "%ld pages freed\n", len);
121 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
122 const struct e820map *e820)
124 phys_addr_t max_addr = PFN_PHYS(max_pfn);
125 phys_addr_t last_end = ISA_END_ADDRESS;
126 unsigned long released = 0;
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);
135 released += xen_release_chunk(last_end, end);
136 last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
139 if (last_end < max_addr)
140 released += xen_release_chunk(last_end, max_addr);
142 printk(KERN_INFO "released %ld pages of unused memory\n", released);
146 static unsigned long __init xen_set_identity(const struct e820entry *list,
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;
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;
165 /* Skip over the 1MB region. */
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));
174 /* Without saving 'last' we would gooble RAM too
175 * at the end of the loop. */
180 start_pci = min(start, start_pci);
183 if (last > start_pci)
184 identity += set_phys_range_identity(
185 PFN_UP(start_pci), PFN_DOWN(last));
189 * machine_specific_memory_setup - Hook for machine specific memory setup.
191 char * __init xen_memory_setup(void)
193 static struct e820entry map[E820MAX] __initdata;
194 static struct e820entry map_raw[E820MAX] __initdata;
196 unsigned long max_pfn = xen_start_info->nr_pages;
197 unsigned long long mem_end;
199 struct xen_memory_map memmap;
200 unsigned long extra_pages = 0;
201 unsigned long extra_limit;
202 unsigned long identity_pages = 0;
206 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
207 mem_end = PFN_PHYS(max_pfn);
209 memmap.nr_entries = E820MAX;
210 set_xen_guest_handle(memmap.buffer, map);
212 op = xen_initial_domain() ?
213 XENMEM_machine_memory_map :
215 rc = HYPERVISOR_memory_op(op, &memmap);
217 BUG_ON(xen_initial_domain());
218 memmap.nr_entries = 1;
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;
228 memcpy(map_raw, map, sizeof(map));
230 xen_extra_mem_start = max((1ULL << 32), mem_end);
231 for (i = 0; i < memmap.nr_entries; i++) {
232 unsigned long long end;
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;
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);
243 map[i].size -= delta;
246 extra_pages += PFN_DOWN(delta);
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).
254 (xen_initial_domain() && end < 0x100000000ULL))
255 e820_add_region(end, delta, E820_UNUSABLE);
258 if (map[i].size > 0 && end > xen_extra_mem_start)
259 xen_extra_mem_start = end;
261 /* Add region if any remains */
263 e820_add_region(map[i].addr, map[i].size, map[i].type);
267 * In domU, the ISA region is normal, usable memory, but we
268 * reserve ISA memory anyway because too many things poke
271 * In Dom0, the host E820 information can leave gaps in the
272 * ISA range, which would cause us to release those pages. To
273 * avoid this, we unconditionally reserve them here.
275 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
282 * See comment above "struct start_info" in <xen/interface/xen.h>
284 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
285 __pa(xen_start_info->pt_base),
288 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
290 extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
293 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
294 * factor the base size. On non-highmem systems, the base
295 * size is the full initial memory allocation; on highmem it
296 * is limited to the max size of lowmem, so that it doesn't
297 * get completely filled.
299 * In principle there could be a problem in lowmem systems if
300 * the initial memory is also very large with respect to
301 * lowmem, but we won't try to deal with that here.
303 extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
304 max_pfn + extra_pages);
306 if (extra_limit >= max_pfn)
307 extra_pages = extra_limit - max_pfn;
311 xen_add_extra_mem(extra_pages);
314 * Set P2M for all non-RAM pages and E820 gaps to be identity
315 * type PFNs. We supply it with the non-sanitized version
318 identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
319 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
324 * Set the bit indicating "nosegneg" library variants should be used.
325 * We only need to bother in pure 32-bit mode; compat 32-bit processes
326 * can have un-truncated segments, so wrapping around is allowed.
328 static void __init fiddle_vdso(void)
332 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
333 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
334 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
335 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
339 static __cpuinit int register_callback(unsigned type, const void *func)
341 struct callback_register callback = {
343 .address = XEN_CALLBACK(__KERNEL_CS, func),
344 .flags = CALLBACKF_mask_events,
347 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
350 void __cpuinit xen_enable_sysenter(void)
353 unsigned sysenter_feature;
356 sysenter_feature = X86_FEATURE_SEP;
358 sysenter_feature = X86_FEATURE_SYSENTER32;
361 if (!boot_cpu_has(sysenter_feature))
364 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
366 setup_clear_cpu_cap(sysenter_feature);
369 void __cpuinit xen_enable_syscall(void)
374 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
376 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
377 /* Pretty fatal; 64-bit userspace has no other
378 mechanism for syscalls. */
381 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
382 ret = register_callback(CALLBACKTYPE_syscall32,
383 xen_syscall32_target);
385 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
387 #endif /* CONFIG_X86_64 */
390 void __init xen_arch_setup(void)
392 xen_panic_handler_init();
394 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
395 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
397 if (!xen_feature(XENFEAT_auto_translated_physmap))
398 HYPERVISOR_vm_assist(VMASST_CMD_enable,
399 VMASST_TYPE_pae_extended_cr3);
401 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
402 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
405 xen_enable_sysenter();
406 xen_enable_syscall();
409 if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
410 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
415 memcpy(boot_command_line, xen_start_info->cmd_line,
416 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
417 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
419 /* Set up idle, making sure it calls safe_halt() pvop */
421 boot_cpu_data.hlt_works_ok = 1;
423 pm_idle = default_idle;
424 boot_option_idle_override = IDLE_HALT;