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)
55 u64 size = (u64)pages * PAGE_SIZE;
56 u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
61 e820_add_region(extra_start, size, E820_RAM);
62 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
64 memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
66 xen_extra_mem_size += size;
68 xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
71 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
74 struct xen_memory_reservation reservation = {
79 unsigned long start, end;
80 unsigned long len = 0;
84 start = PFN_UP(start_addr);
85 end = PFN_DOWN(end_addr);
90 printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
92 for(pfn = start; pfn < end; pfn++) {
93 unsigned long mfn = pfn_to_mfn(pfn);
95 /* Make sure pfn exists to start with */
96 if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
99 set_xen_guest_handle(reservation.extent_start, &mfn);
100 reservation.nr_extents = 1;
102 ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
104 WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
107 set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
111 printk(KERN_CONT "%ld pages freed\n", len);
116 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
117 const struct e820map *e820)
119 phys_addr_t max_addr = PFN_PHYS(max_pfn);
120 phys_addr_t last_end = ISA_END_ADDRESS;
121 unsigned long released = 0;
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);
130 released += xen_release_chunk(last_end, end);
131 last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
134 if (last_end < max_addr)
135 released += xen_release_chunk(last_end, max_addr);
137 printk(KERN_INFO "released %ld pages of unused memory\n", released);
142 * machine_specific_memory_setup - Hook for machine specific memory setup.
144 char * __init xen_memory_setup(void)
146 static struct e820entry map[E820MAX] __initdata;
148 unsigned long max_pfn = xen_start_info->nr_pages;
149 unsigned long long mem_end;
151 struct xen_memory_map memmap;
152 unsigned long extra_pages = 0;
153 unsigned long extra_limit;
157 max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
158 mem_end = PFN_PHYS(max_pfn);
160 memmap.nr_entries = E820MAX;
161 set_xen_guest_handle(memmap.buffer, map);
163 op = xen_initial_domain() ?
164 XENMEM_machine_memory_map :
166 rc = HYPERVISOR_memory_op(op, &memmap);
168 BUG_ON(xen_initial_domain());
169 memmap.nr_entries = 1;
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;
180 xen_extra_mem_start = mem_end;
181 for (i = 0; i < memmap.nr_entries; i++) {
182 unsigned long long end;
184 /* Guard against non-page aligned E820 entries. */
185 if (map[i].type == E820_RAM)
186 map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
188 end = map[i].addr + map[i].size;
189 if (map[i].type == E820_RAM && end > mem_end) {
190 /* RAM off the end - may be partially included */
191 u64 delta = min(map[i].size, end - mem_end);
193 map[i].size -= delta;
196 extra_pages += PFN_DOWN(delta);
199 if (map[i].size > 0 && end > xen_extra_mem_start)
200 xen_extra_mem_start = end;
202 /* Add region if any remains */
204 e820_add_region(map[i].addr, map[i].size, map[i].type);
208 * In domU, the ISA region is normal, usable memory, but we
209 * reserve ISA memory anyway because too many things poke
212 * In Dom0, the host E820 information can leave gaps in the
213 * ISA range, which would cause us to release those pages. To
214 * avoid this, we unconditionally reserve them here.
216 e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
223 * See comment above "struct start_info" in <xen/interface/xen.h>
225 memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
226 __pa(xen_start_info->pt_base),
229 sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
231 extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);
234 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
235 * factor the base size. On non-highmem systems, the base
236 * size is the full initial memory allocation; on highmem it
237 * is limited to the max size of lowmem, so that it doesn't
238 * get completely filled.
240 * In principle there could be a problem in lowmem systems if
241 * the initial memory is also very large with respect to
242 * lowmem, but we won't try to deal with that here.
244 extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
245 max_pfn + extra_pages);
247 if (extra_limit >= max_pfn)
248 extra_pages = extra_limit - max_pfn;
252 xen_add_extra_mem(extra_pages);
258 * Set the bit indicating "nosegneg" library variants should be used.
259 * We only need to bother in pure 32-bit mode; compat 32-bit processes
260 * can have un-truncated segments, so wrapping around is allowed.
262 static void __init fiddle_vdso(void)
266 mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
267 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
268 mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
269 *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
273 static __cpuinit int register_callback(unsigned type, const void *func)
275 struct callback_register callback = {
277 .address = XEN_CALLBACK(__KERNEL_CS, func),
278 .flags = CALLBACKF_mask_events,
281 return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
284 void __cpuinit xen_enable_sysenter(void)
287 unsigned sysenter_feature;
290 sysenter_feature = X86_FEATURE_SEP;
292 sysenter_feature = X86_FEATURE_SYSENTER32;
295 if (!boot_cpu_has(sysenter_feature))
298 ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
300 setup_clear_cpu_cap(sysenter_feature);
303 void __cpuinit xen_enable_syscall(void)
308 ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
310 printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
311 /* Pretty fatal; 64-bit userspace has no other
312 mechanism for syscalls. */
315 if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
316 ret = register_callback(CALLBACKTYPE_syscall32,
317 xen_syscall32_target);
319 setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
321 #endif /* CONFIG_X86_64 */
324 void __init xen_arch_setup(void)
326 xen_panic_handler_init();
328 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
329 HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);
331 if (!xen_feature(XENFEAT_auto_translated_physmap))
332 HYPERVISOR_vm_assist(VMASST_CMD_enable,
333 VMASST_TYPE_pae_extended_cr3);
335 if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
336 register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
339 xen_enable_sysenter();
340 xen_enable_syscall();
343 if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
344 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
349 memcpy(boot_command_line, xen_start_info->cmd_line,
350 MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
351 COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
353 /* Set up idle, making sure it calls safe_halt() pvop */
355 boot_cpu_data.hlt_works_ok = 1;
357 pm_idle = default_idle;