arch/x86/xen/setup.c - kernel/bruno - Git at Google

 /*
  * Machine specific setup for xen
  *
  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  */

 #include <linux/module.h>
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/pm.h>
 #include <linux/memblock.h>

 #include <asm/elf.h>
 #include <asm/vdso.h>
 #include <asm/e820.h>
 #include <asm/setup.h>
 #include <asm/acpi.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>

 #include <xen/xen.h>
 #include <xen/page.h>
 #include <xen/interface/callback.h>
 #include <xen/interface/memory.h>
 #include <xen/interface/physdev.h>
 #include <xen/features.h>

 #include "xen-ops.h"
 #include "vdso.h"

 /* These are code, but not functions.  Defined in entry.S */
 extern const char xen_hypervisor_callback[];
 extern const char xen_failsafe_callback[];
 extern void xen_sysenter_target(void);
 extern void xen_syscall_target(void);
 extern void xen_syscall32_target(void);

 /* Amount of extra memory space we add to the e820 ranges */
 phys_addr_t xen_extra_mem_start, xen_extra_mem_size;

 /*
  * The maximum amount of extra memory compared to the base size.  The
  * main scaling factor is the size of struct page.  At extreme ratios
  * of base:extra, all the base memory can be filled with page
  * structures for the extra memory, leaving no space for anything
  * else.
  *
  * 10x seems like a reasonable balance between scaling flexibility and
  * leaving a practically usable system.
  */
 #define EXTRA_MEM_RATIO		(10)

 static __init void xen_add_extra_mem(unsigned long pages)
 {
 	u64 size = (u64)pages * PAGE_SIZE;
 	u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;

 	if (!pages)
 		return;

 	e820_add_region(extra_start, size, E820_RAM);
 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

 	memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");

 	xen_extra_mem_size += size;

 	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
 }

 static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
 					      phys_addr_t end_addr)
 {
 	struct xen_memory_reservation reservation = {
 		.address_bits = 0,
 		.extent_order = 0,
 		.domid        = DOMID_SELF
 	};
 	unsigned long start, end;
 	unsigned long len = 0;
 	unsigned long pfn;
 	int ret;

 	start = PFN_UP(start_addr);
 	end = PFN_DOWN(end_addr);

 	if (end <= start)
 		return 0;

 	printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
 	       start, end);
 	for(pfn = start; pfn < end; pfn++) {
 		unsigned long mfn = pfn_to_mfn(pfn);

 		/* Make sure pfn exists to start with */
 		if (mfn == INVALID_P2M_ENTRY || mfn_to_pfn(mfn) != pfn)
 			continue;

 		set_xen_guest_handle(reservation.extent_start, &mfn);
 		reservation.nr_extents = 1;

 		ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
 					   &reservation);
 		WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
 		     start, end, ret);
 		if (ret == 1) {
 			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 			len++;
 		}
 	}
 	printk(KERN_CONT "%ld pages freed\n", len);

 	return len;
 }

 static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
 						     const struct e820map *e820)
 {
 	phys_addr_t max_addr = PFN_PHYS(max_pfn);
 	phys_addr_t last_end = ISA_END_ADDRESS;
 	unsigned long released = 0;
 	int i;

 	/* Free any unused memory above the low 1Mbyte. */
 	for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
 		phys_addr_t end = e820->map[i].addr;
 		end = min(max_addr, end);

 		if (last_end < end)
 			released += xen_release_chunk(last_end, end);
 		last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
 	}

 	if (last_end < max_addr)
 		released += xen_release_chunk(last_end, max_addr);

 	printk(KERN_INFO "released %ld pages of unused memory\n", released);
 	return released;
 }

 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
  **/
 char * __init xen_memory_setup(void)
 {
 	static struct e820entry map[E820MAX] __initdata;

 	unsigned long max_pfn = xen_start_info->nr_pages;
 	unsigned long long mem_end;
 	int rc;
 	struct xen_memory_map memmap;
 	unsigned long extra_pages = 0;
 	unsigned long extra_limit;
 	int i;
 	int op;

 	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
 	mem_end = PFN_PHYS(max_pfn);

 	memmap.nr_entries = E820MAX;
 	set_xen_guest_handle(memmap.buffer, map);

 	op = xen_initial_domain() ?
 		XENMEM_machine_memory_map :
 		XENMEM_memory_map;
 	rc = HYPERVISOR_memory_op(op, &memmap);
 	if (rc == -ENOSYS) {
 		BUG_ON(xen_initial_domain());
 		memmap.nr_entries = 1;
 		map[0].addr = 0ULL;
 		map[0].size = mem_end;
 		/* 8MB slack (to balance backend allocations). */
 		map[0].size += 8ULL << 20;
 		map[0].type = E820_RAM;
 		rc = 0;
 	}
 	BUG_ON(rc);

 	e820.nr_map = 0;
 	xen_extra_mem_start = mem_end;
 	for (i = 0; i < memmap.nr_entries; i++) {
 		unsigned long long end = map[i].addr + map[i].size;

 		if (map[i].type == E820_RAM && end > mem_end) {
 			/* RAM off the end - may be partially included */
 			u64 delta = min(map[i].size, end - mem_end);

 			map[i].size -= delta;
 			end -= delta;

 			extra_pages += PFN_DOWN(delta);
 		}

 		if (map[i].size > 0 && end > xen_extra_mem_start)
 			xen_extra_mem_start = end;

 		/* Add region if any remains */
 		if (map[i].size > 0)
 			e820_add_region(map[i].addr, map[i].size, map[i].type);
 	}

 	/*
 	 * In domU, the ISA region is normal, usable memory, but we
 	 * reserve ISA memory anyway because too many things poke
 	 * about in there.
 	 *
 	 * In Dom0, the host E820 information can leave gaps in the
 	 * ISA range, which would cause us to release those pages.  To
 	 * avoid this, we unconditionally reserve them here.
 	 */
 	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 			E820_RESERVED);

 	/*
 	 * Reserve Xen bits:
 	 *  - mfn_list
 	 *  - xen_start_info
 	 * See comment above "struct start_info" in <xen/interface/xen.h>
 	 */
 	memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
 		      __pa(xen_start_info->pt_base),
 			"XEN START INFO");

 	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

 	extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);

 	/*
 	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
 	 * factor the base size.  On non-highmem systems, the base
 	 * size is the full initial memory allocation; on highmem it
 	 * is limited to the max size of lowmem, so that it doesn't
 	 * get completely filled.
 	 *
 	 * In principle there could be a problem in lowmem systems if
 	 * the initial memory is also very large with respect to
 	 * lowmem, but we won't try to deal with that here.
 	 */
 	extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
 			  max_pfn + extra_pages);

 	if (extra_limit >= max_pfn)
 		extra_pages = extra_limit - max_pfn;
 	else
 		extra_pages = 0;

 	xen_add_extra_mem(extra_pages);

 	return "Xen";
 }

 /*
  * Set the bit indicating "nosegneg" library variants should be used.
  * We only need to bother in pure 32-bit mode; compat 32-bit processes
  * can have un-truncated segments, so wrapping around is allowed.
  */
 static void __init fiddle_vdso(void)
 {
 #ifdef CONFIG_X86_32
 	u32 *mask;
 	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
 	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
 	*mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 #endif
 }

 static __cpuinit int register_callback(unsigned type, const void *func)
 {
 	struct callback_register callback = {
 		.type = type,
 		.address = XEN_CALLBACK(__KERNEL_CS, func),
 		.flags = CALLBACKF_mask_events,
 	};

 	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
 }

 void __cpuinit xen_enable_sysenter(void)
 {
 	int ret;
 	unsigned sysenter_feature;

 #ifdef CONFIG_X86_32
 	sysenter_feature = X86_FEATURE_SEP;
 #else
 	sysenter_feature = X86_FEATURE_SYSENTER32;
 #endif

 	if (!boot_cpu_has(sysenter_feature))
 		return;

 	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
 	if(ret != 0)
 		setup_clear_cpu_cap(sysenter_feature);
 }

 void __cpuinit xen_enable_syscall(void)
 {
 #ifdef CONFIG_X86_64
 	int ret;

 	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
 	if (ret != 0) {
 		printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
 		/* Pretty fatal; 64-bit userspace has no other
 		   mechanism for syscalls. */
 	}

 	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
 		ret = register_callback(CALLBACKTYPE_syscall32,
 					xen_syscall32_target);
 		if (ret != 0)
 			setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
 	}
 #endif /* CONFIG_X86_64 */
 }

 void __init xen_arch_setup(void)
 {
 	xen_panic_handler_init();

 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);

 	if (!xen_feature(XENFEAT_auto_translated_physmap))
 		HYPERVISOR_vm_assist(VMASST_CMD_enable,
 				     VMASST_TYPE_pae_extended_cr3);

 	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) ||
 	    register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
 		BUG();

 	xen_enable_sysenter();
 	xen_enable_syscall();

 #ifdef CONFIG_ACPI
 	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
 		disable_acpi();
 	}
 #endif

 	memcpy(boot_command_line, xen_start_info->cmd_line,
 	       MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
 	       COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

 	/* Set up idle, making sure it calls safe_halt() pvop */
 #ifdef CONFIG_X86_32
 	boot_cpu_data.hlt_works_ok = 1;
 #endif
 	pm_idle = default_idle;

 	fiddle_vdso();
 }
	/*
	* Machine specific setup for xen
	*
	* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
	*/

	#include <linux/module.h>
	#include <linux/sched.h>
	#include <linux/mm.h>
	#include <linux/pm.h>
	#include <linux/memblock.h>

	#include <asm/elf.h>
	#include <asm/vdso.h>
	#include <asm/e820.h>
	#include <asm/setup.h>
	#include <asm/acpi.h>
	#include <asm/xen/hypervisor.h>
	#include <asm/xen/hypercall.h>

	#include <xen/xen.h>
	#include <xen/page.h>
	#include <xen/interface/callback.h>
	#include <xen/interface/memory.h>
	#include <xen/interface/physdev.h>
	#include <xen/features.h>

	#include "xen-ops.h"
	#include "vdso.h"

	/* These are code, but not functions. Defined in entry.S */
	extern const char xen_hypervisor_callback[];
	extern const char xen_failsafe_callback[];
	extern void xen_sysenter_target(void);
	extern void xen_syscall_target(void);
	extern void xen_syscall32_target(void);

	/* Amount of extra memory space we add to the e820 ranges */
	phys_addr_t xen_extra_mem_start, xen_extra_mem_size;

	/*
	* The maximum amount of extra memory compared to the base size. The
	* main scaling factor is the size of struct page. At extreme ratios
	* of base:extra, all the base memory can be filled with page
	* structures for the extra memory, leaving no space for anything
	* else.
	*
	* 10x seems like a reasonable balance between scaling flexibility and
	* leaving a practically usable system.
	*/
	#define EXTRA_MEM_RATIO (10)

	static __init void xen_add_extra_mem(unsigned long pages)
	{
	u64 size = (u64)pages * PAGE_SIZE;
	u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;

	if (!pages)
	return;

	e820_add_region(extra_start, size, E820_RAM);
	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

	memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");

	xen_extra_mem_size += size;

	xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
	}

	static unsigned long __init xen_release_chunk(phys_addr_t start_addr,
	phys_addr_t end_addr)
	{
	struct xen_memory_reservation reservation = {
	.address_bits = 0,
	.extent_order = 0,
	.domid = DOMID_SELF
	};
	unsigned long start, end;
	unsigned long len = 0;
	unsigned long pfn;
	int ret;

	start = PFN_UP(start_addr);
	end = PFN_DOWN(end_addr);

	if (end <= start)
	return 0;

	printk(KERN_INFO "xen_release_chunk: looking at area pfn %lx-%lx: ",
	start, end);
	for(pfn = start; pfn < end; pfn++) {
	unsigned long mfn = pfn_to_mfn(pfn);

	/* Make sure pfn exists to start with */
	if (mfn == INVALID_P2M_ENTRY \|\| mfn_to_pfn(mfn) != pfn)
	continue;

	set_xen_guest_handle(reservation.extent_start, &mfn);
	reservation.nr_extents = 1;

	ret = HYPERVISOR_memory_op(XENMEM_decrease_reservation,
	&reservation);
	WARN(ret != 1, "Failed to release memory %lx-%lx err=%d\n",
	start, end, ret);
	if (ret == 1) {
	set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
	len++;
	}
	}
	printk(KERN_CONT "%ld pages freed\n", len);

	return len;
	}

	static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
	const struct e820map *e820)
	{
	phys_addr_t max_addr = PFN_PHYS(max_pfn);
	phys_addr_t last_end = ISA_END_ADDRESS;
	unsigned long released = 0;
	int i;

	/* Free any unused memory above the low 1Mbyte. */
	for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
	phys_addr_t end = e820->map[i].addr;
	end = min(max_addr, end);

	if (last_end < end)
	released += xen_release_chunk(last_end, end);
	last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
	}

	if (last_end < max_addr)
	released += xen_release_chunk(last_end, max_addr);

	printk(KERN_INFO "released %ld pages of unused memory\n", released);
	return released;
	}

	/**
	* machine_specific_memory_setup - Hook for machine specific memory setup.
	**/
	char * __init xen_memory_setup(void)
	{
	static struct e820entry map[E820MAX] __initdata;

	unsigned long max_pfn = xen_start_info->nr_pages;
	unsigned long long mem_end;
	int rc;
	struct xen_memory_map memmap;
	unsigned long extra_pages = 0;
	unsigned long extra_limit;
	int i;
	int op;

	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
	mem_end = PFN_PHYS(max_pfn);

	memmap.nr_entries = E820MAX;
	set_xen_guest_handle(memmap.buffer, map);

	op = xen_initial_domain() ?
	XENMEM_machine_memory_map :
	XENMEM_memory_map;
	rc = HYPERVISOR_memory_op(op, &memmap);
	if (rc == -ENOSYS) {
	BUG_ON(xen_initial_domain());
	memmap.nr_entries = 1;
	map[0].addr = 0ULL;
	map[0].size = mem_end;
	/* 8MB slack (to balance backend allocations). */
	map[0].size += 8ULL << 20;
	map[0].type = E820_RAM;
	rc = 0;
	}
	BUG_ON(rc);

	e820.nr_map = 0;
	xen_extra_mem_start = mem_end;
	for (i = 0; i < memmap.nr_entries; i++) {
	unsigned long long end = map[i].addr + map[i].size;

	if (map[i].type == E820_RAM && end > mem_end) {
	/* RAM off the end - may be partially included */
	u64 delta = min(map[i].size, end - mem_end);

	map[i].size -= delta;
	end -= delta;

	extra_pages += PFN_DOWN(delta);
	}

	if (map[i].size > 0 && end > xen_extra_mem_start)
	xen_extra_mem_start = end;

	/* Add region if any remains */
	if (map[i].size > 0)
	e820_add_region(map[i].addr, map[i].size, map[i].type);
	}

	/*
	* In domU, the ISA region is normal, usable memory, but we
	* reserve ISA memory anyway because too many things poke
	* about in there.
	*
	* In Dom0, the host E820 information can leave gaps in the
	* ISA range, which would cause us to release those pages. To
	* avoid this, we unconditionally reserve them here.
	*/
	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
	E820_RESERVED);

	/*
	* Reserve Xen bits:
	* - mfn_list
	* - xen_start_info
	* See comment above "struct start_info" in <xen/interface/xen.h>
	*/
	memblock_x86_reserve_range(__pa(xen_start_info->mfn_list),
	__pa(xen_start_info->pt_base),
	"XEN START INFO");

	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);

	extra_pages += xen_return_unused_memory(xen_start_info->nr_pages, &e820);

	/*
	* Clamp the amount of extra memory to a EXTRA_MEM_RATIO
	* factor the base size. On non-highmem systems, the base
	* size is the full initial memory allocation; on highmem it
	* is limited to the max size of lowmem, so that it doesn't
	* get completely filled.
	*
	* In principle there could be a problem in lowmem systems if
	* the initial memory is also very large with respect to
	* lowmem, but we won't try to deal with that here.
	*/
	extra_limit = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
	max_pfn + extra_pages);

	if (extra_limit >= max_pfn)
	extra_pages = extra_limit - max_pfn;
	else
	extra_pages = 0;

	xen_add_extra_mem(extra_pages);

	return "Xen";
	}

	/*
	* Set the bit indicating "nosegneg" library variants should be used.
	* We only need to bother in pure 32-bit mode; compat 32-bit processes
	* can have un-truncated segments, so wrapping around is allowed.
	*/
	static void __init fiddle_vdso(void)
	{
	#ifdef CONFIG_X86_32
	u32 *mask;
	mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
	*mask \|= 1 << VDSO_NOTE_NONEGSEG_BIT;
	mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
	*mask \|= 1 << VDSO_NOTE_NONEGSEG_BIT;
	#endif
	}

	static __cpuinit int register_callback(unsigned type, const void *func)
	{
	struct callback_register callback = {
	.type = type,
	.address = XEN_CALLBACK(__KERNEL_CS, func),
	.flags = CALLBACKF_mask_events,
	};

	return HYPERVISOR_callback_op(CALLBACKOP_register, &callback);
	}

	void __cpuinit xen_enable_sysenter(void)
	{
	int ret;
	unsigned sysenter_feature;

	#ifdef CONFIG_X86_32
	sysenter_feature = X86_FEATURE_SEP;
	#else
	sysenter_feature = X86_FEATURE_SYSENTER32;
	#endif

	if (!boot_cpu_has(sysenter_feature))
	return;

	ret = register_callback(CALLBACKTYPE_sysenter, xen_sysenter_target);
	if(ret != 0)
	setup_clear_cpu_cap(sysenter_feature);
	}

	void __cpuinit xen_enable_syscall(void)
	{
	#ifdef CONFIG_X86_64
	int ret;

	ret = register_callback(CALLBACKTYPE_syscall, xen_syscall_target);
	if (ret != 0) {
	printk(KERN_ERR "Failed to set syscall callback: %d\n", ret);
	/* Pretty fatal; 64-bit userspace has no other
	mechanism for syscalls. */
	}

	if (boot_cpu_has(X86_FEATURE_SYSCALL32)) {
	ret = register_callback(CALLBACKTYPE_syscall32,
	xen_syscall32_target);
	if (ret != 0)
	setup_clear_cpu_cap(X86_FEATURE_SYSCALL32);
	}
	#endif /* CONFIG_X86_64 */
	}

	void __init xen_arch_setup(void)
	{
	xen_panic_handler_init();

	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_writable_pagetables);

	if (!xen_feature(XENFEAT_auto_translated_physmap))
	HYPERVISOR_vm_assist(VMASST_CMD_enable,
	VMASST_TYPE_pae_extended_cr3);

	if (register_callback(CALLBACKTYPE_event, xen_hypervisor_callback) \|\|
	register_callback(CALLBACKTYPE_failsafe, xen_failsafe_callback))
	BUG();

	xen_enable_sysenter();
	xen_enable_syscall();

	#ifdef CONFIG_ACPI
	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
	printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
	disable_acpi();
	}
	#endif

	memcpy(boot_command_line, xen_start_info->cmd_line,
	MAX_GUEST_CMDLINE > COMMAND_LINE_SIZE ?
	COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

	/* Set up idle, making sure it calls safe_halt() pvop */
	#ifdef CONFIG_X86_32
	boot_cpu_data.hlt_works_ok = 1;
	#endif
	pm_idle = default_idle;

	fiddle_vdso();
	}