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) {
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 = mem_end;
231 for (i = 0; i < memmap.nr_entries; i++) {
232 unsigned long long end = map[i].addr + map[i].size;
234 if (map[i].type == E820_RAM && end > mem_end) {
235 /* RAM off the end - may be partially included */
236 u64 delta = min(map[i].size, end - mem_end);
238 map[i].size -= delta;
241 extra_pages += PFN_DOWN(delta);
244 if (map[i].size > 0 && end > xen_extra_mem_start)
245 xen_extra_mem_start = end;
247 /* Add region if any remains */
249 e820_add_region(map[i].addr, map[i].size, map[i].type);
253 * In domU, the ISA region is normal, usable memory, but we
254 * reserve ISA memory anyway because too many things poke
257 * In Dom0, the host E820 information can leave gaps in the
258 * ISA range, which would cause us to release those pages. To
259 * avoid this, we unconditionally reserve them here.
261 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
268 * See comment above "struct start_info" in <xen/interface/xen.h>
270 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
271 __pa(xen_start_info->pt_base),
274 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
276 extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
279 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
280 * factor the base size. On non-highmem systems, the base
281 * size is the full initial memory allocation; on highmem it
282 * is limited to the max size of lowmem, so that it doesn't
283 * get completely filled.
285 * In principle there could be a problem in lowmem systems if
286 * the initial memory is also very large with respect to
287 * lowmem, but we won't try to deal with that here.
289 extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
290 max_pfn + extra_pages);
292 if (extra_limit >= max_pfn)
293 extra_pages = extra_limit - max_pfn;
297 xen_add_extra_mem(extra_pages);
300 * Set P2M for all non-RAM pages and E820 gaps to be identity
301 * type PFNs. We supply it with the non-sanitized version
304 identity_pages = xen_set_identity(map_raw, memmap.nr_entries);
305 printk(KERN_INFO "Set %ld page(s) to 1-1 mapping.\n", identity_pages);
310 * Set the bit indicating "nosegneg" library variants should be used.
311 * We only need to bother in pure 32-bit mode; compat 32-bit processes
312 * can have un-truncated segments, so wrapping around is allowed.
314 static void __init fiddle_vdso(void)
318 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
319 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
320 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
321 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
325 static __cpuinit int register_callback(unsigned type, const void *func)
327 struct callback_register callback = {
329 .address = XEN_CALLBACK(__KERNEL_CS, func),
330 .flags = CALLBACKF_mask_events,
333 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
336 void __cpuinit xen_enable_sysenter(void)
339 unsigned sysenter_feature;
342 sysenter_feature = X86_FEATURE_SEP;
344 sysenter_feature = X86_FEATURE_SYSENTER32;
347 if (!boot_cpu_has(sysenter_feature))
350 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
352 setup_clear_cpu_cap(sysenter_feature);
355 void __cpuinit xen_enable_syscall(void)
360 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
362 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
363 /* Pretty fatal; 64-bit userspace has no other
364 mechanism for syscalls. */
367 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
368 ret = register_callback(CALLBACKTYPE_syscall32,
369 xen_syscall32_target);
371 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
373 #endif /* CONFIG_X86_64 */
376 void __init xen_arch_setup(void)
378 xen_panic_handler_init();
380 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
381 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
383 if (!xen_feature(XENFEAT_auto_translated_physmap))
384 HYPERVISOR_vm_assist(VMASST_CMD_enable,
385 VMASST_TYPE_pae_extended_cr3);
387 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
388 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
391 xen_enable_sysenter();
392 xen_enable_syscall();
395 if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
396 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
401 memcpy(boot_command_line, xen_start_info->cmd_line,
402 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
403 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
405 /* Set up idle, making sure it calls safe_halt() pvop */
407 boot_cpu_data.hlt_works_ok = 1;
409 pm_idle = default_idle;