Merge tag 'for-linus-4.3-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen updates from David Vrabel:
 "Xen features and fixes for 4.3:

   - Convert xen-blkfront to the multiqueue API
   - [arm] Support binding event channels to different VCPUs.
   - [x86] Support > 512 GiB in a PV guests (off by default as such a
     guest cannot be migrated with the current toolstack).
   - [x86] PMU support for PV dom0 (limited support for using perf with
     Xen and other guests)"

* tag 'for-linus-4.3-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (33 commits)
  xen: switch extra memory accounting to use pfns
  xen: limit memory to architectural maximum
  xen: avoid another early crash of memory limited dom0
  xen: avoid early crash of memory limited dom0
  arm/xen: Remove helpers which are PV specific
  xen/x86: Don't try to set PCE bit in CR4
  xen/PMU: PMU emulation code
  xen/PMU: Intercept PMU-related MSR and APIC accesses
  xen/PMU: Describe vendor-specific PMU registers
  xen/PMU: Initialization code for Xen PMU
  xen/PMU: Sysfs interface for setting Xen PMU mode
  xen: xensyms support
  xen: remove no longer needed p2m.h
  xen: allow more than 512 GB of RAM for 64 bit pv-domains
  xen: move p2m list if conflicting with e820 map
  xen: add explicit memblock_reserve() calls for special pages
  mm: provide early_memremap_ro to establish read-only mapping
  xen: check for initrd conflicting with e820 map
  xen: check pre-allocated page tables for conflict with memory map
  xen: check for kernel memory conflicting with memory layout
  ...

15 files changed, 1435 insertions, 215 deletions

diff --git a/arch/x86/xen/Kconfig b/arch/x86/xen/Kconfig
index 4841453..c7b15f3 100644
--- a/arch/x86/xen/Kconfig
+++ b/arch/x86/xen/Kconfig
@@ -7,6 +7,7 @@ config XEN
 	depends on PARAVIRT
 	select PARAVIRT_CLOCK
 	select XEN_HAVE_PVMMU
+	select XEN_HAVE_VPMU
 	depends on X86_64 || (X86_32 && X86_PAE)
 	depends on X86_LOCAL_APIC && X86_TSC
 	help
@@ -23,14 +24,18 @@ config XEN_PVHVM
 	def_bool y
 	depends on XEN && PCI && X86_LOCAL_APIC
 
-config XEN_MAX_DOMAIN_MEMORY
-       int
-       default 500 if X86_64
-       default 64 if X86_32
-       depends on XEN
-       help
-         This only affects the sizing of some bss arrays, the unused
-         portions of which are freed.
+config XEN_512GB
+	bool "Limit Xen pv-domain memory to 512GB"
+	depends on XEN && X86_64
+	default y
+	help
+	  Limit paravirtualized user domains to 512GB of RAM.
+
+	  The Xen tools and crash dump analysis tools might not support
+	  pv-domains with more than 512 GB of RAM. This option controls the
+	  default setting of the kernel to use only up to 512 GB or more.
+	  It is always possible to change the default via specifying the
+	  boot parameter "xen_512gb_limit".
 
 config XEN_SAVE_RESTORE
        bool
diff --git a/arch/x86/xen/Makefile b/arch/x86/xen/Makefile
index 4b6e29a..e47e527 100644
--- a/arch/x86/xen/Makefile
+++ b/arch/x86/xen/Makefile
@@ -13,7 +13,7 @@ CFLAGS_mmu.o			:= $(nostackp)
 obj-y		:= enlighten.o setup.o multicalls.o mmu.o irq.o \
 			time.o xen-asm.o xen-asm_$(BITS).o \
 			grant-table.o suspend.o platform-pci-unplug.o \
-			p2m.o apic.o
+			p2m.o apic.o pmu.o
 
 obj-$(CONFIG_EVENT_TRACING) += trace.o
 
diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
index 70e060a..acda713 100644
--- a/arch/x86/xen/apic.c
+++ b/arch/x86/xen/apic.c
@@ -7,6 +7,7 @@
 #include <xen/xen.h>
 #include <xen/interface/physdev.h>
 #include "xen-ops.h"
+#include "pmu.h"
 #include "smp.h"
 
 static unsigned int xen_io_apic_read(unsigned apic, unsigned reg)
@@ -72,6 +73,11 @@ static u32 xen_apic_read(u32 reg)
 
 static void xen_apic_write(u32 reg, u32 val)
 {
+	if (reg == APIC_LVTPC) {
+		(void)pmu_apic_update(reg);
+		return;
+	}
+
 	/* Warn to see if there's any stray references */
 	WARN(1,"register: %x, value: %x\n", reg, val);
 }
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index d9cfa45..30d12af 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -84,6 +84,7 @@
 #include "mmu.h"
 #include "smp.h"
 #include "multicalls.h"
+#include "pmu.h"
 
 EXPORT_SYMBOL_GPL(hypercall_page);
 
@@ -1010,8 +1011,7 @@ static void xen_write_cr0(unsigned long cr0)
 
 static void xen_write_cr4(unsigned long cr4)
 {
-	cr4 &= ~X86_CR4_PGE;
-	cr4 &= ~X86_CR4_PSE;
+	cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
 
 	native_write_cr4(cr4);
 }
@@ -1030,6 +1030,9 @@ static u64 xen_read_msr_safe(unsigned int msr, int *err)
 {
 	u64 val;
 
+	if (pmu_msr_read(msr, &val, err))
+		return val;
+
 	val = native_read_msr_safe(msr, err);
 	switch (msr) {
 	case MSR_IA32_APICBASE:
@@ -1076,7 +1079,8 @@ static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
 		   Xen console noise. */
 
 	default:
-		ret = native_write_msr_safe(msr, low, high);
+		if (!pmu_msr_write(msr, low, high, &ret))
+			ret = native_write_msr_safe(msr, low, high);
 	}
 
 	return ret;
@@ -1215,7 +1219,7 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = {
 	.read_msr = xen_read_msr_safe,
 	.write_msr = xen_write_msr_safe,
 
-	.read_pmc = native_read_pmc,
+	.read_pmc = xen_read_pmc,
 
 	.iret = xen_iret,
 #ifdef CONFIG_X86_64
@@ -1264,6 +1268,10 @@ static const struct pv_apic_ops xen_apic_ops __initconst = {
 static void xen_reboot(int reason)
 {
 	struct sched_shutdown r = { .reason = reason };
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		xen_pmu_finish(cpu);
 
 	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
 		BUG();
@@ -1607,7 +1615,9 @@ asmlinkage __visible void __init xen_start_kernel(void)
 	early_boot_irqs_disabled = true;
 
 	xen_raw_console_write("mapping kernel into physical memory\n");
-	xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base, xen_start_info->nr_pages);
+	xen_setup_kernel_pagetable((pgd_t *)xen_start_info->pt_base,
+				   xen_start_info->nr_pages);
+	xen_reserve_special_pages();
 
 	/*
 	 * Modify the cache mode translation tables to match Xen's PAT
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dd151b2..2c50b44 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -116,6 +116,7 @@ static pud_t level3_user_vsyscall[PTRS_PER_PUD] __page_aligned_bss;
 DEFINE_PER_CPU(unsigned long, xen_cr3);	 /* cr3 stored as physaddr */
 DEFINE_PER_CPU(unsigned long, xen_current_cr3);	 /* actual vcpu cr3 */
 
+static phys_addr_t xen_pt_base, xen_pt_size __initdata;
 
 /*
  * Just beyond the highest usermode address.  STACK_TOP_MAX has a
@@ -1093,6 +1094,16 @@ static void xen_exit_mmap(struct mm_struct *mm)
 
 static void xen_post_allocator_init(void);
 
+static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
+{
+	struct mmuext_op op;
+
+	op.cmd = cmd;
+	op.arg1.mfn = pfn_to_mfn(pfn);
+	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+		BUG();
+}
+
 #ifdef CONFIG_X86_64
 static void __init xen_cleanhighmap(unsigned long vaddr,
 				    unsigned long vaddr_end)
@@ -1114,6 +1125,83 @@ static void __init xen_cleanhighmap(unsigned long vaddr,
 	xen_mc_flush();
 }
 
+/*
+ * Make a page range writeable and free it.
+ */
+static void __init xen_free_ro_pages(unsigned long paddr, unsigned long size)
+{
+	void *vaddr = __va(paddr);
+	void *vaddr_end = vaddr + size;
+
+	for (; vaddr < vaddr_end; vaddr += PAGE_SIZE)
+		make_lowmem_page_readwrite(vaddr);
+
+	memblock_free(paddr, size);
+}
+
+static void __init xen_cleanmfnmap_free_pgtbl(void *pgtbl, bool unpin)
+{
+	unsigned long pa = __pa(pgtbl) & PHYSICAL_PAGE_MASK;
+
+	if (unpin)
+		pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(pa));
+	ClearPagePinned(virt_to_page(__va(pa)));
+	xen_free_ro_pages(pa, PAGE_SIZE);
+}
+
+/*
+ * Since it is well isolated we can (and since it is perhaps large we should)
+ * also free the page tables mapping the initial P->M table.
+ */
+static void __init xen_cleanmfnmap(unsigned long vaddr)
+{
+	unsigned long va = vaddr & PMD_MASK;
+	unsigned long pa;
+	pgd_t *pgd = pgd_offset_k(va);
+	pud_t *pud_page = pud_offset(pgd, 0);
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *pte;
+	unsigned int i;
+	bool unpin;
+
+	unpin = (vaddr == 2 * PGDIR_SIZE);
+	set_pgd(pgd, __pgd(0));
+	do {
+		pud = pud_page + pud_index(va);
+		if (pud_none(*pud)) {
+			va += PUD_SIZE;
+		} else if (pud_large(*pud)) {
+			pa = pud_val(*pud) & PHYSICAL_PAGE_MASK;
+			xen_free_ro_pages(pa, PUD_SIZE);
+			va += PUD_SIZE;
+		} else {
+			pmd = pmd_offset(pud, va);
+			if (pmd_large(*pmd)) {
+				pa = pmd_val(*pmd) & PHYSICAL_PAGE_MASK;
+				xen_free_ro_pages(pa, PMD_SIZE);
+			} else if (!pmd_none(*pmd)) {
+				pte = pte_offset_kernel(pmd, va);
+				set_pmd(pmd, __pmd(0));
+				for (i = 0; i < PTRS_PER_PTE; ++i) {
+					if (pte_none(pte[i]))
+						break;
+					pa = pte_pfn(pte[i]) << PAGE_SHIFT;
+					xen_free_ro_pages(pa, PAGE_SIZE);
+				}
+				xen_cleanmfnmap_free_pgtbl(pte, unpin);
+			}
+			va += PMD_SIZE;
+			if (pmd_index(va))
+				continue;
+			set_pud(pud, __pud(0));
+			xen_cleanmfnmap_free_pgtbl(pmd, unpin);
+		}
+
+	} while (pud_index(va) || pmd_index(va));
+	xen_cleanmfnmap_free_pgtbl(pud_page, unpin);
+}
+
 static void __init xen_pagetable_p2m_free(void)
 {
 	unsigned long size;
@@ -1128,18 +1216,31 @@ static void __init xen_pagetable_p2m_free(void)
 	/* using __ka address and sticking INVALID_P2M_ENTRY! */
 	memset((void *)xen_start_info->mfn_list, 0xff, size);
 
-	/* We should be in __ka space. */
-	BUG_ON(xen_start_info->mfn_list < __START_KERNEL_map);
 	addr = xen_start_info->mfn_list;
-	/* We roundup to the PMD, which means that if anybody at this stage is
-	 * using the __ka address of xen_start_info or xen_start_info->shared_info
-	 * they are in going to crash. Fortunatly we have already revectored
-	 * in xen_setup_kernel_pagetable and in xen_setup_shared_info. */
+	/*
+	 * We could be in __ka space.
+	 * We roundup to the PMD, which means that if anybody at this stage is
+	 * using the __ka address of xen_start_info or
+	 * xen_start_info->shared_info they are in going to crash. Fortunatly
+	 * we have already revectored in xen_setup_kernel_pagetable and in
+	 * xen_setup_shared_info.
+	 */
 	size = roundup(size, PMD_SIZE);
-	xen_cleanhighmap(addr, addr + size);
 
-	size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
-	memblock_free(__pa(xen_start_info->mfn_list), size);
+	if (addr >= __START_KERNEL_map) {
+		xen_cleanhighmap(addr, addr + size);
+		size = PAGE_ALIGN(xen_start_info->nr_pages *
+				  sizeof(unsigned long));
+		memblock_free(__pa(addr), size);
+	} else {
+		xen_cleanmfnmap(addr);
+	}
+}
+
+static void __init xen_pagetable_cleanhighmap(void)
+{
+	unsigned long size;
+	unsigned long addr;
 
 	/* At this stage, cleanup_highmap has already cleaned __ka space
 	 * from _brk_limit way up to the max_pfn_mapped (which is the end of
@@ -1172,6 +1273,8 @@ static void __init xen_pagetable_p2m_setup(void)
 
 #ifdef CONFIG_X86_64
 	xen_pagetable_p2m_free();
+
+	xen_pagetable_cleanhighmap();
 #endif
 	/* And revector! Bye bye old array */
 	xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
@@ -1461,6 +1564,24 @@ static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
 #else /* CONFIG_X86_64 */
 static pte_t __init mask_rw_pte(pte_t *ptep, pte_t pte)
 {
+	unsigned long pfn;
+
+	if (xen_feature(XENFEAT_writable_page_tables) ||
+	    xen_feature(XENFEAT_auto_translated_physmap) ||
+	    xen_start_info->mfn_list >= __START_KERNEL_map)
+		return pte;
+
+	/*
+	 * Pages belonging to the initial p2m list mapped outside the default
+	 * address range must be mapped read-only. This region contains the
+	 * page tables for mapping the p2m list, too, and page tables MUST be
+	 * mapped read-only.
+	 */
+	pfn = pte_pfn(pte);
+	if (pfn >= xen_start_info->first_p2m_pfn &&
+	    pfn < xen_start_info->first_p2m_pfn + xen_start_info->nr_p2m_frames)
+		pte = __pte_ma(pte_val_ma(pte) & ~_PAGE_RW);
+
 	return pte;
 }
 #endif /* CONFIG_X86_64 */
@@ -1489,15 +1610,6 @@ static void __init xen_set_pte_init(pte_t *ptep, pte_t pte)
 	native_set_pte(ptep, pte);
 }
 
-static void __init pin_pagetable_pfn(unsigned cmd, unsigned long pfn)
-{
-	struct mmuext_op op;
-	op.cmd = cmd;
-	op.arg1.mfn = pfn_to_mfn(pfn);
-	if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
-		BUG();
-}
-
 /* Early in boot, while setting up the initial pagetable, assume
    everything is pinned. */
 static void __init xen_alloc_pte_init(struct mm_struct *mm, unsigned long pfn)
@@ -1815,7 +1927,10 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
 	 * mappings. Considering that on Xen after the kernel mappings we
 	 * have the mappings of some pages that don't exist in pfn space, we
 	 * set max_pfn_mapped to the last real pfn mapped. */
-	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+	if (xen_start_info->mfn_list < __START_KERNEL_map)
+		max_pfn_mapped = xen_start_info->first_p2m_pfn;
+	else
+		max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
 
 	pt_base = PFN_DOWN(__pa(xen_start_info->pt_base));
 	pt_end = pt_base + xen_start_info->nr_pt_frames;
@@ -1855,6 +1970,11 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
 	/* Graft it onto L4[511][510] */
 	copy_page(level2_kernel_pgt, l2);
 
+	/* Copy the initial P->M table mappings if necessary. */
+	i = pgd_index(xen_start_info->mfn_list);
+	if (i && i < pgd_index(__START_KERNEL_map))
+		init_level4_pgt[i] = ((pgd_t *)xen_start_info->pt_base)[i];
+
 	if (!xen_feature(XENFEAT_auto_translated_physmap)) {
 		/* Make pagetable pieces RO */
 		set_page_prot(init_level4_pgt, PAGE_KERNEL_RO);
@@ -1894,10 +2014,192 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
 		check_pt_base(&pt_base, &pt_end, addr[i]);
 
 	/* Our (by three pages) smaller Xen pagetable that we are using */
-	memblock_reserve(PFN_PHYS(pt_base), (pt_end - pt_base) * PAGE_SIZE);
+	xen_pt_base = PFN_PHYS(pt_base);
+	xen_pt_size = (pt_end - pt_base) * PAGE_SIZE;
+	memblock_reserve(xen_pt_base, xen_pt_size);
+
 	/* Revector the xen_start_info */
 	xen_start_info = (struct start_info *)__va(__pa(xen_start_info));
 }
+
+/*
+ * Read a value from a physical address.
+ */
+static unsigned long __init xen_read_phys_ulong(phys_addr_t addr)
+{
+	unsigned long *vaddr;
+	unsigned long val;
+
+	vaddr = early_memremap_ro(addr, sizeof(val));
+	val = *vaddr;
+	early_memunmap(vaddr, sizeof(val));
+	return val;
+}
+
+/*
+ * Translate a virtual address to a physical one without relying on mapped
+ * page tables.
+ */
+static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
+{
+	phys_addr_t pa;
+	pgd_t pgd;
+	pud_t pud;
+	pmd_t pmd;
+	pte_t pte;
+
+	pa = read_cr3();
+	pgd = native_make_pgd(xen_read_phys_ulong(pa + pgd_index(vaddr) *
+						       sizeof(pgd)));
+	if (!pgd_present(pgd))
+		return 0;
+
+	pa = pgd_val(pgd) & PTE_PFN_MASK;
+	pud = native_make_pud(xen_read_phys_ulong(pa + pud_index(vaddr) *
+						       sizeof(pud)));
+	if (!pud_present(pud))
+		return 0;
+	pa = pud_pfn(pud) << PAGE_SHIFT;
+	if (pud_large(pud))
+		return pa + (vaddr & ~PUD_MASK);
+
+	pmd = native_make_pmd(xen_read_phys_ulong(pa + pmd_index(vaddr) *
+						       sizeof(pmd)));
+	if (!pmd_present(pmd))
+		return 0;
+	pa = pmd_pfn(pmd) << PAGE_SHIFT;
+	if (pmd_large(pmd))
+		return pa + (vaddr & ~PMD_MASK);
+
+	pte = native_make_pte(xen_read_phys_ulong(pa + pte_index(vaddr) *
+						       sizeof(pte)));
+	if (!pte_present(pte))
+		return 0;
+	pa = pte_pfn(pte) << PAGE_SHIFT;
+
+	return pa | (vaddr & ~PAGE_MASK);
+}
+
+/*
+ * Find a new area for the hypervisor supplied p2m list and relocate the p2m to
+ * this area.
+ */
+void __init xen_relocate_p2m(void)
+{
+	phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
+	unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
+	int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
+	pte_t *pt;
+	pmd_t *pmd;
+	pud_t *pud;
+	pgd_t *pgd;
+	unsigned long *new_p2m;
+
+	size = PAGE_ALIGN(xen_start_info->nr_pages * sizeof(unsigned long));
+	n_pte = roundup(size, PAGE_SIZE) >> PAGE_SHIFT;
+	n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
+	n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
+	n_pud = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
+	n_frames = n_pte + n_pt + n_pmd + n_pud;
+
+	new_area = xen_find_free_area(PFN_PHYS(n_frames));
+	if (!new_area) {
+		xen_raw_console_write("Can't find new memory area for p2m needed due to E820 map conflict\n");
+		BUG();
+	}
+
+	/*
+	 * Setup the page tables for addressing the new p2m list.
+	 * We have asked the hypervisor to map the p2m list at the user address
+	 * PUD_SIZE. It may have done so, or it may have used a kernel space
+	 * address depending on the Xen version.
+	 * To avoid any possible virtual address collision, just use
+	 * 2 * PUD_SIZE for the new area.
+	 */
+	pud_phys = new_area;
+	pmd_phys = pud_phys + PFN_PHYS(n_pud);
+	pt_phys = pmd_phys + PFN_PHYS(n_pmd);
+	p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
+
+	pgd = __va(read_cr3());
+	new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
+	for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
+		pud = early_memremap(pud_phys, PAGE_SIZE);
+		clear_page(pud);
+		for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
+		     idx_pmd++) {
+			pmd = early_memremap(pmd_phys, PAGE_SIZE);
+			clear_page(pmd);
+			for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
+			     idx_pt++) {
+				pt = early_memremap(pt_phys, PAGE_SIZE);
+				clear_page(pt);
+				for (idx_pte = 0;
+				     idx_pte < min(n_pte, PTRS_PER_PTE);
+				     idx_pte++) {
+					set_pte(pt + idx_pte,
+						pfn_pte(p2m_pfn, PAGE_KERNEL));
+					p2m_pfn++;
+				}
+				n_pte -= PTRS_PER_PTE;
+				early_memunmap(pt, PAGE_SIZE);
+				make_lowmem_page_readonly(__va(pt_phys));
+				pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
+						  PFN_DOWN(pt_phys));
+				set_pmd(pmd + idx_pt,
+					__pmd(_PAGE_TABLE | pt_phys));
+				pt_phys += PAGE_SIZE;
+			}
+			n_pt -= PTRS_PER_PMD;
+			early_memunmap(pmd, PAGE_SIZE);
+			make_lowmem_page_readonly(__va(pmd_phys));
+			pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
+					  PFN_DOWN(pmd_phys));
+			set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
+			pmd_phys += PAGE_SIZE;
+		}
+		n_pmd -= PTRS_PER_PUD;
+		early_memunmap(pud, PAGE_SIZE);
+		make_lowmem_page_readonly(__va(pud_phys));
+		pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
+		set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
+		pud_phys += PAGE_SIZE;
+	}
+
+	/* Now copy the old p2m info to the new area. */
+	memcpy(new_p2m, xen_p2m_addr, size);
+	xen_p2m_addr = new_p2m;
+
+	/* Release the old p2m list and set new list info. */
+	p2m_pfn = PFN_DOWN(xen_early_virt_to_phys(xen_start_info->mfn_list));
+	BUG_ON(!p2m_pfn);
+	p2m_pfn_end = p2m_pfn + PFN_DOWN(size);
+
+	if (xen_start_info->mfn_list < __START_KERNEL_map) {
+		pfn = xen_start_info->first_p2m_pfn;
+		pfn_end = xen_start_info->first_p2m_pfn +
+			  xen_start_info->nr_p2m_frames;
+		set_pgd(pgd + 1, __pgd(0));
+	} else {
+		pfn = p2m_pfn;
+		pfn_end = p2m_pfn_end;
+	}
+
+	memblock_free(PFN_PHYS(pfn), PAGE_SIZE * (pfn_end - pfn));
+	while (pfn < pfn_end) {
+		if (pfn == p2m_pfn) {
+			pfn = p2m_pfn_end;
+			continue;
+		}
+		make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+		pfn++;
+	}
+
+	xen_start_info->mfn_list = (unsigned long)xen_p2m_addr;
+	xen_start_info->first_p2m_pfn =  PFN_DOWN(new_area);
+	xen_start_info->nr_p2m_frames = n_frames;
+}
+
 #else	/* !CONFIG_X86_64 */
 static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
 static RESERVE_BRK_ARRAY(pmd_t, swapper_kernel_pmd, PTRS_PER_PMD);
@@ -1938,18 +2240,41 @@ static void __init xen_write_cr3_init(unsigned long cr3)
 	pv_mmu_ops.write_cr3 = &xen_write_cr3;
 }
 
+/*
+ * For 32 bit domains xen_start_info->pt_base is the pgd address which might be
+ * not the first page table in the page table pool.
+ * Iterate through the initial page tables to find the real page table base.
+ */
+static phys_addr_t xen_find_pt_base(pmd_t *pmd)
+{
+	phys_addr_t pt_base, paddr;
+	unsigned pmdidx;
+
+	pt_base = min(__pa(xen_start_info->pt_base), __pa(pmd));
+
+	for (pmdidx = 0; pmdidx < PTRS_PER_PMD; pmdidx++)
+		if (pmd_present(pmd[pmdidx]) && !pmd_large(pmd[pmdidx])) {
+			paddr = m2p(pmd[pmdidx].pmd);
+			pt_base = min(pt_base, paddr);
+		}
+
+	return pt_base;
+}
+
 void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
 {
 	pmd_t *kernel_pmd;
 
+	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
+
+	xen_pt_base = xen_find_pt_base(kernel_pmd);
+	xen_pt_size = xen_start_info->nr_pt_frames * PAGE_SIZE;
+
 	initial_kernel_pmd =
 		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
 
-	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
-				  xen_start_info->nr_pt_frames * PAGE_SIZE +
-				  512*1024);
+	max_pfn_mapped = PFN_DOWN(xen_pt_base + xen_pt_size + 512 * 1024);
 
-	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
 	copy_page(initial_kernel_pmd, kernel_pmd);
 
 	xen_map_identity_early(initial_kernel_pmd, max_pfn);
@@ -1968,11 +2293,33 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
 			  PFN_DOWN(__pa(initial_page_table)));
 	xen_write_cr3(__pa(initial_page_table));
 
-	memblock_reserve(__pa(xen_start_info->pt_base),
-			 xen_start_info->nr_pt_frames * PAGE_SIZE);
+	memblock_reserve(xen_pt_base, xen_pt_size);
 }
 #endif	/* CONFIG_X86_64 */
 
+void __init xen_reserve_special_pages(void)
+{
+	phys_addr_t paddr;
+
+	memblock_reserve(__pa(xen_start_info), PAGE_SIZE);
+	if (xen_start_info->store_mfn) {
+		paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->store_mfn));
+		memblock_reserve(paddr, PAGE_SIZE);
+	}
+	if (!xen_initial_domain()) {
+		paddr = PFN_PHYS(mfn_to_pfn(xen_start_info->console.domU.mfn));
+		memblock_reserve(paddr, PAGE_SIZE);
+	}
+}
+
+void __init xen_pt_check_e820(void)
+{
+	if (xen_is_e820_reserved(xen_pt_base, xen_pt_size)) {
+		xen_raw_console_write("Xen hypervisor allocated page table memory conflicts with E820 map\n");
+		BUG();
+	}
+}
+
 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
 
 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c
index 8b7f18e..bfc08b1 100644
--- a/arch/x86/xen/p2m.c
+++ b/arch/x86/xen/p2m.c
@@ -79,10 +79,14 @@
 #include <xen/balloon.h>
 #include <xen/grant_table.h>
 
-#include "p2m.h"
 #include "multicalls.h"
 #include "xen-ops.h"
 
+#define P2M_MID_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long *))
+#define P2M_TOP_PER_PAGE	(PAGE_SIZE / sizeof(unsigned long **))
+
+#define MAX_P2M_PFN	(P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
+
 #define PMDS_PER_MID_PAGE	(P2M_MID_PER_PAGE / PTRS_PER_PTE)
 
 unsigned long *xen_p2m_addr __read_mostly;
@@ -199,7 +203,8 @@ void __ref xen_build_mfn_list_list(void)
 	unsigned int level, topidx, mididx;
 	unsigned long *mid_mfn_p;
 
-	if (xen_feature(XENFEAT_auto_translated_physmap))
+	if (xen_feature(XENFEAT_auto_translated_physmap) ||
+	    xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
 		return;
 
 	/* Pre-initialize p2m_top_mfn to be completely missing */
@@ -260,9 +265,16 @@ void xen_setup_mfn_list_list(void)
 
 	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
 
-	HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
-		virt_to_mfn(p2m_top_mfn);
+	if (xen_start_info->flags & SIF_VIRT_P2M_4TOOLS)
+		HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list = ~0UL;
+	else
+		HYPERVISOR_shared_info->arch.pfn_to_mfn_frame_list_list =
+			virt_to_mfn(p2m_top_mfn);
 	HYPERVISOR_shared_info->arch.max_pfn = xen_max_p2m_pfn;
+	HYPERVISOR_shared_info->arch.p2m_generation = 0;
+	HYPERVISOR_shared_info->arch.p2m_vaddr = (unsigned long)xen_p2m_addr;
+	HYPERVISOR_shared_info->arch.p2m_cr3 =
+		xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
 }
 
 /* Set up p2m_top to point to the domain-builder provided p2m pages */
@@ -478,8 +490,12 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
 
 		ptechk = lookup_address(vaddr, &level);
 		if (ptechk == pte_pg) {
+			HYPERVISOR_shared_info->arch.p2m_generation++;
+			wmb(); /* Tools are synchronizing via p2m_generation. */
 			set_pmd(pmdp,
 				__pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE));
+			wmb(); /* Tools are synchronizing via p2m_generation. */
+			HYPERVISOR_shared_info->arch.p2m_generation++;
 			pte_newpg[i] = NULL;
 		}
 
@@ -505,7 +521,7 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg)
  */
 static bool alloc_p2m(unsigned long pfn)
 {
-	unsigned topidx, mididx;
+	unsigned topidx;
 	unsigned long *top_mfn_p, *mid_mfn;
 	pte_t *ptep, *pte_pg;
 	unsigned int level;
@@ -513,9 +529,6 @@ static bool alloc_p2m(unsigned long pfn)
 	unsigned long addr = (unsigned long)(xen_p2m_addr + pfn);
 	unsigned long p2m_pfn;
 
-	topidx = p2m_top_index(pfn);
-	mididx = p2m_mid_index(pfn);
-
 	ptep = lookup_address(addr, &level);
 	BUG_ON(!ptep || level != PG_LEVEL_4K);
 	pte_pg = (pte_t *)((unsigned long)ptep & ~(PAGE_SIZE - 1));
@@ -527,7 +540,8 @@ static bool alloc_p2m(unsigned long pfn)
 			return false;
 	}
 
-	if (p2m_top_mfn) {
+	if (p2m_top_mfn && pfn < MAX_P2M_PFN) {
+		topidx = p2m_top_index(pfn);
 		top_mfn_p = &p2m_top_mfn[topidx];
 		mid_mfn = ACCESS_ONCE(p2m_top_mfn_p[topidx]);
 
@@ -577,10 +591,14 @@ static bool alloc_p2m(unsigned long pfn)
 		spin_lock_irqsave(&p2m_update_lock, flags);
 
 		if (pte_pfn(*ptep) == p2m_pfn) {
+			HYPERVISOR_shared_info->arch.p2m_generation++;
+			wmb(); /* Tools are synchronizing via p2m_generation. */
 			set_pte(ptep,
 				pfn_pte(PFN_DOWN(__pa(p2m)), PAGE_KERNEL));
+			wmb(); /* Tools are synchronizing via p2m_generation. */
+			HYPERVISOR_shared_info->arch.p2m_generation++;
 			if (mid_mfn)
-				mid_mfn[mididx] = virt_to_mfn(p2m);
+				mid_mfn[p2m_mid_index(pfn)] = virt_to_mfn(p2m);
 			p2m = NULL;
 		}
 
@@ -630,6 +648,11 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 		return true;
 	}
 
+	/*
+	 * The interface requires atomic updates on p2m elements.
+	 * xen_safe_write_ulong() is using __put_user which does an atomic
+	 * store via asm().
+	 */
 	if (likely(!xen_safe_write_ulong(xen_p2m_addr + pfn, mfn)))
 		return true;
 
diff --git a/arch/x86/xen/p2m.h b/arch/x86/xen/p2m.h
deleted file mode 100644
index ad8aee2..0000000
--- a/arch/x86/xen/p2m.h
+++ /dev/null
@@ -1,15 +0,0 @@
-#ifndef _XEN_P2M_H
-#define _XEN_P2M_H
-
-#define P2M_PER_PAGE        (PAGE_SIZE / sizeof(unsigned long))
-#define P2M_MID_PER_PAGE    (PAGE_SIZE / sizeof(unsigned long *))
-#define P2M_TOP_PER_PAGE    (PAGE_SIZE / sizeof(unsigned long **))
-
-#define MAX_P2M_PFN         (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE)
-
-#define MAX_REMAP_RANGES    10
-
-extern unsigned long __init set_phys_range_identity(unsigned long pfn_s,
-                                      unsigned long pfn_e);
-
-#endif  /* _XEN_P2M_H */
diff --git a/arch/x86/xen/platform-pci-unplug.c b/arch/x86/xen/platform-pci-unplug.c
index a826171..9586ff3 100644
--- a/arch/x86/xen/platform-pci-unplug.c
+++ b/arch/x86/xen/platform-pci-unplug.c
@@ -68,7 +68,7 @@ static int check_platform_magic(void)
 	return 0;
 }
 
-bool xen_has_pv_devices()
+bool xen_has_pv_devices(void)
 {
 	if (!xen_domain())
 		return false;
diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
new file mode 100644
index 0000000..724a087
--- /dev/null
+++ b/arch/x86/xen/pmu.c
@@ -0,0 +1,570 @@
+#include <linux/types.h>
+#include <linux/interrupt.h>
+
+#include <asm/xen/hypercall.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/vcpu.h>
+#include <xen/interface/xenpmu.h>
+
+#include "xen-ops.h"
+#include "pmu.h"
+
+/* x86_pmu.handle_irq definition */
+#include "../kernel/cpu/perf_event.h"
+
+#define XENPMU_IRQ_PROCESSING    1
+struct xenpmu {
+	/* Shared page between hypervisor and domain */
+	struct xen_pmu_data *xenpmu_data;
+
+	uint8_t flags;
+};
+static DEFINE_PER_CPU(struct xenpmu, xenpmu_shared);
+#define get_xenpmu_data()    (this_cpu_ptr(&xenpmu_shared)->xenpmu_data)
+#define get_xenpmu_flags()   (this_cpu_ptr(&xenpmu_shared)->flags)
+
+/* Macro for computing address of a PMU MSR bank */
+#define field_offset(ctxt, field) ((void *)((uintptr_t)ctxt + \
+					    (uintptr_t)ctxt->field))
+
+/* AMD PMU */
+#define F15H_NUM_COUNTERS   6
+#define F10H_NUM_COUNTERS   4
+
+static __read_mostly uint32_t amd_counters_base;
+static __read_mostly uint32_t amd_ctrls_base;
+static __read_mostly int amd_msr_step;
+static __read_mostly int k7_counters_mirrored;
+static __read_mostly int amd_num_counters;
+
+/* Intel PMU */
+#define MSR_TYPE_COUNTER            0
+#define MSR_TYPE_CTRL               1
+#define MSR_TYPE_GLOBAL             2
+#define MSR_TYPE_ARCH_COUNTER       3
+#define MSR_TYPE_ARCH_CTRL          4
+
+/* Number of general pmu registers (CPUID.EAX[0xa].EAX[8..15]) */
+#define PMU_GENERAL_NR_SHIFT        8
+#define PMU_GENERAL_NR_BITS         8
+#define PMU_GENERAL_NR_MASK         (((1 << PMU_GENERAL_NR_BITS) - 1) \
+				     << PMU_GENERAL_NR_SHIFT)
+
+/* Number of fixed pmu registers (CPUID.EDX[0xa].EDX[0..4]) */
+#define PMU_FIXED_NR_SHIFT          0
+#define PMU_FIXED_NR_BITS           5
+#define PMU_FIXED_NR_MASK           (((1 << PMU_FIXED_NR_BITS) - 1) \
+				     << PMU_FIXED_NR_SHIFT)
+
+/* Alias registers (0x4c1) for full-width writes to PMCs */
+#define MSR_PMC_ALIAS_MASK          (~(MSR_IA32_PERFCTR0 ^ MSR_IA32_PMC0))
+
+#define INTEL_PMC_TYPE_SHIFT        30
+
+static __read_mostly int intel_num_arch_counters, intel_num_fixed_counters;
+
+
+static void xen_pmu_arch_init(void)
+{
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
+
+		switch (boot_cpu_data.x86) {
+		case 0x15:
+			amd_num_counters = F15H_NUM_COUNTERS;
+			amd_counters_base = MSR_F15H_PERF_CTR;
+			amd_ctrls_base = MSR_F15H_PERF_CTL;
+			amd_msr_step = 2;
+			k7_counters_mirrored = 1;
+			break;
+		case 0x10:
+		case 0x12:
+		case 0x14:
+		case 0x16:
+		default:
+			amd_num_counters = F10H_NUM_COUNTERS;
+			amd_counters_base = MSR_K7_PERFCTR0;
+			amd_ctrls_base = MSR_K7_EVNTSEL0;
+			amd_msr_step = 1;
+			k7_counters_mirrored = 0;
+			break;
+		}
+	} else {
+		uint32_t eax, ebx, ecx, edx;
+
+		cpuid(0xa, &eax, &ebx, &ecx, &edx);
+
+		intel_num_arch_counters = (eax & PMU_GENERAL_NR_MASK) >>
+			PMU_GENERAL_NR_SHIFT;
+		intel_num_fixed_counters = (edx & PMU_FIXED_NR_MASK) >>
+			PMU_FIXED_NR_SHIFT;
+	}
+}
+
+static inline uint32_t get_fam15h_addr(u32 addr)
+{
+	switch (addr) {
+	case MSR_K7_PERFCTR0:
+	case MSR_K7_PERFCTR1:
+	case MSR_K7_PERFCTR2:
+	case MSR_K7_PERFCTR3:
+		return MSR_F15H_PERF_CTR + (addr - MSR_K7_PERFCTR0);
+	case MSR_K7_EVNTSEL0:
+	case MSR_K7_EVNTSEL1:
+	case MSR_K7_EVNTSEL2:
+	case MSR_K7_EVNTSEL3:
+		return MSR_F15H_PERF_CTL + (addr - MSR_K7_EVNTSEL0);
+	default:
+		break;
+	}
+
+	return addr;
+}
+
+static inline bool is_amd_pmu_msr(unsigned int msr)
+{
+	if ((msr >= MSR_F15H_PERF_CTL &&
+	     msr < MSR_F15H_PERF_CTR + (amd_num_counters * 2)) ||
+	    (msr >= MSR_K7_EVNTSEL0 &&
+	     msr < MSR_K7_PERFCTR0 + amd_num_counters))
+		return true;
+
+	return false;
+}
+
+static int is_intel_pmu_msr(u32 msr_index, int *type, int *index)
+{
+	u32 msr_index_pmc;
+
+	switch (msr_index) {
+	case MSR_CORE_PERF_FIXED_CTR_CTRL:
+	case MSR_IA32_DS_AREA:
+	case MSR_IA32_PEBS_ENABLE:
+		*type = MSR_TYPE_CTRL;
+		return true;
+
+	case MSR_CORE_PERF_GLOBAL_CTRL:
+	case MSR_CORE_PERF_GLOBAL_STATUS:
+	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+		*type = MSR_TYPE_GLOBAL;
+		return true;
+
+	default:
+
+		if ((msr_index >= MSR_CORE_PERF_FIXED_CTR0) &&
+		    (msr_index < MSR_CORE_PERF_FIXED_CTR0 +
+				 intel_num_fixed_counters)) {
+			*index = msr_index - MSR_CORE_PERF_FIXED_CTR0;
+			*type = MSR_TYPE_COUNTER;
+			return true;
+		}
+
+		if ((msr_index >= MSR_P6_EVNTSEL0) &&
+		    (msr_index < MSR_P6_EVNTSEL0 +  intel_num_arch_counters)) {
+			*index = msr_index - MSR_P6_EVNTSEL0;
+			*type = MSR_TYPE_ARCH_CTRL;
+			return true;
+		}
+
+		msr_index_pmc = msr_index & MSR_PMC_ALIAS_MASK;
+		if ((msr_index_pmc >= MSR_IA32_PERFCTR0) &&
+		    (msr_index_pmc < MSR_IA32_PERFCTR0 +
+				     intel_num_arch_counters)) {
+			*type = MSR_TYPE_ARCH_COUNTER;
+			*index = msr_index_pmc - MSR_IA32_PERFCTR0;
+			return true;
+		}
+		return false;
+	}
+}
+
+static bool xen_intel_pmu_emulate(unsigned int msr, u64 *val, int type,
+				  int index, bool is_read)
+{
+	uint64_t *reg = NULL;
+	struct xen_pmu_intel_ctxt *ctxt;
+	uint64_t *fix_counters;
+	struct xen_pmu_cntr_pair *arch_cntr_pair;
+	struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+	uint8_t xenpmu_flags = get_xenpmu_flags();
+
+
+	if (!xenpmu_data || !(xenpmu_flags & XENPMU_IRQ_PROCESSING))
+		return false;
+
+	ctxt = &xenpmu_data->pmu.c.intel;
+
+	switch (msr) {
+	case MSR_CORE_PERF_GLOBAL_OVF_CTRL:
+		reg = &ctxt->global_ovf_ctrl;
+		break;
+	case MSR_CORE_PERF_GLOBAL_STATUS:
+		reg = &ctxt->global_status;
+		break;
+	case MSR_CORE_PERF_GLOBAL_CTRL:
+		reg = &ctxt->global_ctrl;
+		break;
+	case MSR_CORE_PERF_FIXED_CTR_CTRL:
+		reg = &ctxt->fixed_ctrl;
+		break;
+	default:
+		switch (type) {
+		case MSR_TYPE_COUNTER:
+			fix_counters = field_offset(ctxt, fixed_counters);
+			reg = &fix_counters[index];
+			break;
+		case MSR_TYPE_ARCH_COUNTER:
+			arch_cntr_pair = field_offset(ctxt, arch_counters);
+			reg = &arch_cntr_pair[index].counter;
+			break;
+		case MSR_TYPE_ARCH_CTRL:
+			arch_cntr_pair = field_offset(ctxt, arch_counters);
+			reg = &arch_cntr_pair[index].control;
+			break;
+		default:
+			return false;
+		}
+	}
+
+	if (reg) {
+		if (is_read)
+			*val = *reg;
+		else {
+			*reg = *val;
+
+			if (msr == MSR_CORE_PERF_GLOBAL_OVF_CTRL)
+				ctxt->global_status &= (~(*val));
+		}
+		return true;
+	}
+
+	return false;
+}
+
+static bool xen_amd_pmu_emulate(unsigned int msr, u64 *val, bool is_read)
+{
+	uint64_t *reg = NULL;
+	int i, off = 0;
+	struct xen_pmu_amd_ctxt *ctxt;
+	uint64_t *counter_regs, *ctrl_regs;
+	struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+	uint8_t xenpmu_flags = get_xenpmu_flags();
+
+	if (!xenpmu_data || !(xenpmu_flags & XENPMU_IRQ_PROCESSING))
+		return false;
+
+	if (k7_counters_mirrored &&
+	    ((msr >= MSR_K7_EVNTSEL0) && (msr <= MSR_K7_PERFCTR3)))
+		msr = get_fam15h_addr(msr);
+
+	ctxt = &xenpmu_data->pmu.c.amd;
+	for (i = 0; i < amd_num_counters; i++) {
+		if (msr == amd_ctrls_base + off) {
+			ctrl_regs = field_offset(ctxt, ctrls);
+			reg = &ctrl_regs[i];
+			break;
+		} else if (msr == amd_counters_base + off) {
+			counter_regs = field_offset(ctxt, counters);
+			reg = &counter_regs[i];
+			break;
+		}
+		off += amd_msr_step;
+	}
+
+	if (reg) {
+		if (is_read)
+			*val = *reg;
+		else
+			*reg = *val;
+
+		return true;
+	}
+	return false;
+}
+
+bool pmu_msr_read(unsigned int msr, uint64_t *val, int *err)
+{
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
+		if (is_amd_pmu_msr(msr)) {
+			if (!xen_amd_pmu_emulate(msr, val, 1))
+				*val = native_read_msr_safe(msr, err);
+			return true;
+		}
+	} else {
+		int type, index;
+
+		if (is_intel_pmu_msr(msr, &type, &index)) {
+			if (!xen_intel_pmu_emulate(msr, val, type, index, 1))
+				*val = native_read_msr_safe(msr, err);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool pmu_msr_write(unsigned int msr, uint32_t low, uint32_t high, int *err)
+{
+	uint64_t val = ((uint64_t)high << 32) | low;
+
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) {
+		if (is_amd_pmu_msr(msr)) {
+			if (!xen_amd_pmu_emulate(msr, &val, 0))
+				*err = native_write_msr_safe(msr, low, high);
+			return true;
+		}
+	} else {
+		int type, index;
+
+		if (is_intel_pmu_msr(msr, &type, &index)) {
+			if (!xen_intel_pmu_emulate(msr, &val, type, index, 0))
+				*err = native_write_msr_safe(msr, low, high);
+			return true;
+		}
+	}
+
+	return false;
+}
+
+static unsigned long long xen_amd_read_pmc(int counter)
+{
+	struct xen_pmu_amd_ctxt *ctxt;
+	uint64_t *counter_regs;
+	struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+	uint8_t xenpmu_flags = get_xenpmu_flags();
+
+	if (!xenpmu_data || !(xenpmu_flags & XENPMU_IRQ_PROCESSING)) {
+		uint32_t msr;
+		int err;
+
+		msr = amd_counters_base + (counter * amd_msr_step);
+		return native_read_msr_safe(msr, &err);
+	}
+
+	ctxt = &xenpmu_data->pmu.c.amd;
+	counter_regs = field_offset(ctxt, counters);
+	return counter_regs[counter];
+}
+
+static unsigned long long xen_intel_read_pmc(int counter)
+{
+	struct xen_pmu_intel_ctxt *ctxt;
+	uint64_t *fixed_counters;
+	struct xen_pmu_cntr_pair *arch_cntr_pair;
+	struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+	uint8_t xenpmu_flags = get_xenpmu_flags();
+
+	if (!xenpmu_data || !(xenpmu_flags & XENPMU_IRQ_PROCESSING)) {
+		uint32_t msr;
+		int err;
+
+		if (counter & (1 << INTEL_PMC_TYPE_SHIFT))
+			msr = MSR_CORE_PERF_FIXED_CTR0 + (counter & 0xffff);
+		else
+			msr = MSR_IA32_PERFCTR0 + counter;
+
+		return native_read_msr_safe(msr, &err);
+	}
+
+	ctxt = &xenpmu_data->pmu.c.intel;
+	if (counter & (1 << INTEL_PMC_TYPE_SHIFT)) {
+		fixed_counters = field_offset(ctxt, fixed_counters);
+		return fixed_counters[counter & 0xffff];
+	}
+
+	arch_cntr_pair = field_offset(ctxt, arch_counters);
+	return arch_cntr_pair[counter].counter;
+}
+
+unsigned long long xen_read_pmc(int counter)
+{
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
+		return xen_amd_read_pmc(counter);
+	else
+		return xen_intel_read_pmc(counter);
+}
+
+int pmu_apic_update(uint32_t val)
+{
+	int ret;
+	struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+
+	if (!xenpmu_data) {
+		pr_warn_once("%s: pmudata not initialized\n", __func__);
+		return -EINVAL;
+	}
+
+	xenpmu_data->pmu.l.lapic_lvtpc = val;
+
+	if (get_xenpmu_flags() & XENPMU_IRQ_PROCESSING)
+		return 0;
+
+	ret = HYPERVISOR_xenpmu_op(XENPMU_lvtpc_set, NULL);
+
+	return ret;
+}
+
+/* perf callbacks */
+static int xen_is_in_guest(void)
+{
+	const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+
+	if (!xenpmu_data) {
+		pr_warn_once("%s: pmudata not initialized\n", __func__);
+		return 0;
+	}
+
+	if (!xen_initial_domain() || (xenpmu_data->domain_id >= DOMID_SELF))
+		return 0;
+
+	return 1;
+}
+
+static int xen_is_user_mode(void)
+{
+	const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+
+	if (!xenpmu_data) {
+		pr_warn_once("%s: pmudata not initialized\n", __func__);
+		return 0;
+	}
+
+	if (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_PV)
+		return (xenpmu_data->pmu.pmu_flags & PMU_SAMPLE_USER);
+	else
+		return !!(xenpmu_data->pmu.r.regs.cpl & 3);
+}
+
+static unsigned long xen_get_guest_ip(void)
+{
+	const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+
+	if (!xenpmu_data) {
+		pr_warn_once("%s: pmudata not initialized\n", __func__);
+		return 0;
+	}
+
+	return xenpmu_data->pmu.r.regs.ip;
+}
+
+static struct perf_guest_info_callbacks xen_guest_cbs = {
+	.is_in_guest            = xen_is_in_guest,
+	.is_user_mode           = xen_is_user_mode,
+	.get_guest_ip           = xen_get_guest_ip,
+};
+
+/* Convert registers from Xen's format to Linux' */
+static void xen_convert_regs(const struct xen_pmu_regs *xen_regs,
+			     struct pt_regs *regs, uint64_t pmu_flags)
+{
+	regs->ip = xen_regs->ip;
+	regs->cs = xen_regs->cs;
+	regs->sp = xen_regs->sp;
+
+	if (pmu_flags & PMU_SAMPLE_PV) {
+		if (pmu_flags & PMU_SAMPLE_USER)
+			regs->cs |= 3;
+		else
+			regs->cs &= ~3;
+	} else {
+		if (xen_regs->cpl)
+			regs->cs |= 3;
+		else
+			regs->cs &= ~3;
+	}
+}
+
+irqreturn_t xen_pmu_irq_handler(int irq, void *dev_id)
+{
+	int err, ret = IRQ_NONE;
+	struct pt_regs regs;
+	const struct xen_pmu_data *xenpmu_data = get_xenpmu_data();
+	uint8_t xenpmu_flags = get_xenpmu_flags();
+
+	if (!xenpmu_data) {
+		pr_warn_once("%s: pmudata not initialized\n", __func__);
+		return ret;
+	}
+
+	this_cpu_ptr(&xenpmu_shared)->flags =
+		xenpmu_flags | XENPMU_IRQ_PROCESSING;
+	xen_convert_regs(&xenpmu_data->pmu.r.regs, &regs,
+			 xenpmu_data->pmu.pmu_flags);
+	if (x86_pmu.handle_irq(&regs))
+		ret = IRQ_HANDLED;
+
+	/* Write out cached context to HW */
+	err = HYPERVISOR_xenpmu_op(XENPMU_flush, NULL);
+	this_cpu_ptr(&xenpmu_shared)->flags = xenpmu_flags;
+	if (err) {
+		pr_warn_once("%s: failed hypercall, err: %d\n", __func__, err);
+		return IRQ_NONE;
+	}
+
+	return ret;
+}
+
+bool is_xen_pmu(int cpu)
+{
+	return (get_xenpmu_data() != NULL);
+}
+
+void xen_pmu_init(int cpu)
+{
+	int err;
+	struct xen_pmu_params xp;
+	unsigned long pfn;
+	struct xen_pmu_data *xenpmu_data;
+
+	BUILD_BUG_ON(sizeof(struct xen_pmu_data) > PAGE_SIZE);
+
+	if (xen_hvm_domain())
+		return;
+
+	xenpmu_data = (struct xen_pmu_data *)get_zeroed_page(GFP_KERNEL);
+	if (!xenpmu_data) {
+		pr_err("VPMU init: No memory\n");
+		return;
+	}
+	pfn = virt_to_pfn(xenpmu_data);
+
+	xp.val = pfn_to_mfn(pfn);
+	xp.vcpu = cpu;
+	xp.version.maj = XENPMU_VER_MAJ;
+	xp.version.min = XENPMU_VER_MIN;
+	err = HYPERVISOR_xenpmu_op(XENPMU_init, &xp);
+	if (err)
+		goto fail;
+
+	per_cpu(xenpmu_shared, cpu).xenpmu_data = xenpmu_data;
+	per_cpu(xenpmu_shared, cpu).flags = 0;
+
+	if (cpu == 0) {
+		perf_register_guest_info_callbacks(&xen_guest_cbs);
+		xen_pmu_arch_init();
+	}
+
+	return;
+
+fail:
+	pr_warn_once("Could not initialize VPMU for cpu %d, error %d\n",
+		cpu, err);
+	free_pages((unsigned long)xenpmu_data, 0);
+}
+
+void xen_pmu_finish(int cpu)
+{
+	struct xen_pmu_params xp;
+
+	if (xen_hvm_domain())
+		return;
+
+	xp.vcpu = cpu;
+	xp.version.maj = XENPMU_VER_MAJ;
+	xp.version.min = XENPMU_VER_MIN;
+
+	(void)HYPERVISOR_xenpmu_op(XENPMU_finish, &xp);
+
+	free_pages((unsigned long)per_cpu(xenpmu_shared, cpu).xenpmu_data, 0);
+	per_cpu(xenpmu_shared, cpu).xenpmu_data = NULL;
+}
diff --git a/arch/x86/xen/pmu.h b/arch/x86/xen/pmu.h
new file mode 100644
index 0000000..af5f0ad
--- /dev/null
+++ b/arch/x86/xen/pmu.h
@@ -0,0 +1,15 @@
+#ifndef __XEN_PMU_H
+#define __XEN_PMU_H
+
+#include <xen/interface/xenpmu.h>
+
+irqreturn_t xen_pmu_irq_handler(int irq, void *dev_id);
+void xen_pmu_init(int cpu);
+void xen_pmu_finish(int cpu);
+bool is_xen_pmu(int cpu);
+bool pmu_msr_read(unsigned int msr, uint64_t *val, int *err);
+bool pmu_msr_write(unsigned int msr, uint32_t low, uint32_t high, int *err);
+int pmu_apic_update(uint32_t reg);
+unsigned long long xen_read_pmc(int counter);
+
+#endif /* __XEN_PMU_H */
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 55f388e..f5ef674 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -27,17 +27,23 @@
 #include <xen/interface/memory.h>
 #include <xen/interface/physdev.h>
 #include <xen/features.h>
+#include <xen/hvc-console.h>
 #include "xen-ops.h"
 #include "vdso.h"
-#include "p2m.h"
 #include "mmu.h"
 
+#define GB(x) ((uint64_t)(x) * 1024 * 1024 * 1024)
+
 /* Amount of extra memory space we add to the e820 ranges */
 struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
 
 /* Number of pages released from the initial allocation. */
 unsigned long xen_released_pages;
 
+/* E820 map used during setting up memory. */
+static struct e820entry xen_e820_map[E820MAX] __initdata;
+static u32 xen_e820_map_entries __initdata;
+
 /*
  * Buffer used to remap identity mapped pages. We only need the virtual space.
  * The physical page behind this address is remapped as needed to different
@@ -64,62 +70,89 @@ static unsigned long xen_remap_mfn __initdata = INVALID_P2M_ENTRY;
  */
 #define EXTRA_MEM_RATIO		(10)
 
-static void __init xen_add_extra_mem(phys_addr_t start, phys_addr_t size)
+static bool xen_512gb_limit __initdata = IS_ENABLED(CONFIG_XEN_512GB);
+
+static void __init xen_parse_512gb(void)
+{
+	bool val = false;
+	char *arg;
+
+	arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit");
+	if (!arg)
+		return;
+
+	arg = strstr(xen_start_info->cmd_line, "xen_512gb_limit=");
+	if (!arg)
+		val = true;
+	else if (strtobool(arg + strlen("xen_512gb_limit="), &val))
+		return;
+
+	xen_512gb_limit = val;
+}
+
+static void __init xen_add_extra_mem(unsigned long start_pfn,
+				     unsigned long n_pfns)
 {
 	int i;
 
+	/*
+	 * No need to check for zero size, should happen rarely and will only
+	 * write a new entry regarded to be unused due to zero size.
+	 */
 	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
 		/* Add new region. */
-		if (xen_extra_mem[i].size == 0) {
-			xen_extra_mem[i].start = start;
-			xen_extra_mem[i].size  = size;
+		if (xen_extra_mem[i].n_pfns == 0) {
+			xen_extra_mem[i].start_pfn = start_pfn;
+			xen_extra_mem[i].n_pfns = n_pfns;
 			break;
 		}
 		/* Append to existing region. */
-		if (xen_extra_mem[i].start + xen_extra_mem[i].size == start) {
-			xen_extra_mem[i].size += size;
+		if (xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns ==
+		    start_pfn) {
+			xen_extra_mem[i].n_pfns += n_pfns;
 			break;
 		}
 	}
 	if (i == XEN_EXTRA_MEM_MAX_REGIONS)
 		printk(KERN_WARNING "Warning: not enough extra memory regions\n");
 
-	memblock_reserve(start, size);
+	memblock_reserve(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
 }
 
-static void __init xen_del_extra_mem(phys_addr_t start, phys_addr_t size)
+static void __init xen_del_extra_mem(unsigned long start_pfn,
+				     unsigned long n_pfns)
 {
 	int i;
-	phys_addr_t start_r, size_r;
+	unsigned long start_r, size_r;
 
 	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
-		start_r = xen_extra_mem[i].start;
-		size_r = xen_extra_mem[i].size;
+		start_r = xen_extra_mem[i].start_pfn;
+		size_r = xen_extra_mem[i].n_pfns;
 
 		/* Start of region. */
-		if (start_r == start) {
-			BUG_ON(size > size_r);
-			xen_extra_mem[i].start += size;
-			xen_extra_mem[i].size -= size;
+		if (start_r == start_pfn) {
+			BUG_ON(n_pfns > size_r);
+			xen_extra_mem[i].start_pfn += n_pfns;
+			xen_extra_mem[i].n_pfns -= n_pfns;
 			break;
 		}
 		/* End of region. */
-		if (start_r + size_r == start + size) {
-			BUG_ON(size > size_r);
-			xen_extra_mem[i].size -= size;
+		if (start_r + size_r == start_pfn + n_pfns) {
+			BUG_ON(n_pfns > size_r);
+			xen_extra_mem[i].n_pfns -= n_pfns;
 			break;
 		}
 		/* Mid of region. */
-		if (start > start_r && start < start_r + size_r) {
-			BUG_ON(start + size > start_r + size_r);
-			xen_extra_mem[i].size = start - start_r;
+		if (start_pfn > start_r && start_pfn < start_r + size_r) {
+			BUG_ON(start_pfn + n_pfns > start_r + size_r);
+			xen_extra_mem[i].n_pfns = start_pfn - start_r;
 			/* Calling memblock_reserve() again is okay. */
-			xen_add_extra_mem(start + size, start_r + size_r -
-					  (start + size));
+			xen_add_extra_mem(start_pfn + n_pfns, start_r + size_r -
+					  (start_pfn + n_pfns));
 			break;
 		}
 	}
-	memblock_free(start, size);
+	memblock_free(PFN_PHYS(start_pfn), PFN_PHYS(n_pfns));
 }
 
 /*
@@ -130,11 +163,10 @@ static void __init xen_del_extra_mem(phys_addr_t start, phys_addr_t size)
 unsigned long __ref xen_chk_extra_mem(unsigned long pfn)
 {
 	int i;
-	phys_addr_t addr = PFN_PHYS(pfn);
 
 	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
-		if (addr >= xen_extra_mem[i].start &&
-		    addr < xen_extra_mem[i].start + xen_extra_mem[i].size)
+		if (pfn >= xen_extra_mem[i].start_pfn &&
+		    pfn < xen_extra_mem[i].start_pfn + xen_extra_mem[i].n_pfns)
 			return INVALID_P2M_ENTRY;
 	}
 
@@ -150,10 +182,10 @@ void __init xen_inv_extra_mem(void)
 	int i;
 
 	for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++) {
-		if (!xen_extra_mem[i].size)
+		if (!xen_extra_mem[i].n_pfns)
 			continue;
-		pfn_s = PFN_DOWN(xen_extra_mem[i].start);
-		pfn_e = PFN_UP(xen_extra_mem[i].start + xen_extra_mem[i].size);
+		pfn_s = xen_extra_mem[i].start_pfn;
+		pfn_e = pfn_s + xen_extra_mem[i].n_pfns;
 		for (pfn = pfn_s; pfn < pfn_e; pfn++)
 			set_phys_to_machine(pfn, INVALID_P2M_ENTRY);
 	}
@@ -164,15 +196,13 @@ void __init xen_inv_extra_mem(void)
  * This function updates min_pfn with the pfn found and returns
  * the size of that range or zero if not found.
  */
-static unsigned long __init xen_find_pfn_range(
-	const struct e820entry *list, size_t map_size,
-	unsigned long *min_pfn)
+static unsigned long __init xen_find_pfn_range(unsigned long *min_pfn)
 {
-	const struct e820entry *entry;
+	const struct e820entry *entry = xen_e820_map;
 	unsigned int i;
 	unsigned long done = 0;
 
-	for (i = 0, entry = list; i < map_size; i++, entry++) {
+	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
 		unsigned long s_pfn;
 		unsigned long e_pfn;
 
@@ -221,7 +251,7 @@ static int __init xen_free_mfn(unsigned long mfn)
  * as a fallback if the remapping fails.
  */
 static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
-	unsigned long end_pfn, unsigned long nr_pages, unsigned long *released)
+			unsigned long end_pfn, unsigned long nr_pages)
 {
 	unsigned long pfn, end;
 	int ret;
@@ -241,7 +271,7 @@ static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
 		WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
 
 		if (ret == 1) {
-			(*released)++;
+			xen_released_pages++;
 			if (!__set_phys_to_machine(pfn, INVALID_P2M_ENTRY))
 				break;
 		} else
@@ -356,9 +386,8 @@ static void __init xen_do_set_identity_and_remap_chunk(
  * to Xen and not remapped.
  */
 static unsigned long __init xen_set_identity_and_remap_chunk(
-        const struct e820entry *list, size_t map_size, unsigned long start_pfn,
-	unsigned long end_pfn, unsigned long nr_pages, unsigned long remap_pfn,
-	unsigned long *released, unsigned long *remapped)
+	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+	unsigned long remap_pfn)
 {
 	unsigned long pfn;
 	unsigned long i = 0;
@@ -379,12 +408,11 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 		if (cur_pfn + size > nr_pages)
 			size = nr_pages - cur_pfn;
 
-		remap_range_size = xen_find_pfn_range(list, map_size,
-						      &remap_pfn);
+		remap_range_size = xen_find_pfn_range(&remap_pfn);
 		if (!remap_range_size) {
 			pr_warning("Unable to find available pfn range, not remapping identity pages\n");
 			xen_set_identity_and_release_chunk(cur_pfn,
-				cur_pfn + left, nr_pages, released);
+						cur_pfn + left, nr_pages);
 			break;
 		}
 		/* Adjust size to fit in current e820 RAM region */
@@ -396,7 +424,6 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 		/* Update variables to reflect new mappings. */
 		i += size;
 		remap_pfn += size;
-		*remapped += size;
 	}
 
 	/*
@@ -411,15 +438,11 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 	return remap_pfn;
 }
 
-static void __init xen_set_identity_and_remap(
-	const struct e820entry *list, size_t map_size, unsigned long nr_pages,
-	unsigned long *released, unsigned long *remapped)
+static void __init xen_set_identity_and_remap(unsigned long nr_pages)
 {
 	phys_addr_t start = 0;
 	unsigned long last_pfn = nr_pages;
-	const struct e820entry *entry;
-	unsigned long num_released = 0;
-	unsigned long num_remapped = 0;
+	const struct e820entry *entry = xen_e820_map;
 	int i;
 
 	/*
@@ -433,9 +456,9 @@ static void __init xen_set_identity_and_remap(
 	 * example) the DMI tables in a reserved region that begins on
 	 * a non-page boundary.
 	 */
-	for (i = 0, entry = list; i < map_size; i++, entry++) {
+	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
 		phys_addr_t end = entry->addr + entry->size;
-		if (entry->type == E820_RAM || i == map_size - 1) {
+		if (entry->type == E820_RAM || i == xen_e820_map_entries - 1) {
 			unsigned long start_pfn = PFN_DOWN(start);
 			unsigned long end_pfn = PFN_UP(end);
 
@@ -444,17 +467,13 @@ static void __init xen_set_identity_and_remap(
 
 			if (start_pfn < end_pfn)
 				last_pfn = xen_set_identity_and_remap_chunk(
-						list, map_size, start_pfn,
-						end_pfn, nr_pages, last_pfn,
-						&num_released, &num_remapped);
+						start_pfn, end_pfn, nr_pages,
+						last_pfn);
 			start = end;
 		}
 	}
 
-	*released = num_released;
-	*remapped = num_remapped;
-
-	pr_info("Released %ld page(s)\n", num_released);
+	pr_info("Released %ld page(s)\n", xen_released_pages);
 }
 
 /*
@@ -494,7 +513,7 @@ void __init xen_remap_memory(void)
 		} else if (pfn_s + len == xen_remap_buf.target_pfn) {
 			len += xen_remap_buf.size;
 		} else {
-			xen_del_extra_mem(PFN_PHYS(pfn_s), PFN_PHYS(len));
+			xen_del_extra_mem(pfn_s, len);
 			pfn_s = xen_remap_buf.target_pfn;
 			len = xen_remap_buf.size;
 		}
@@ -504,19 +523,36 @@ void __init xen_remap_memory(void)
 	}
 
 	if (pfn_s != ~0UL && len)
-		xen_del_extra_mem(PFN_PHYS(pfn_s), PFN_PHYS(len));
+		xen_del_extra_mem(pfn_s, len);
 
 	set_pte_mfn(buf, mfn_save, PAGE_KERNEL);
 
 	pr_info("Remapped %ld page(s)\n", remapped);
 }
 
+static unsigned long __init xen_get_pages_limit(void)
+{
+	unsigned long limit;
+
+#ifdef CONFIG_X86_32
+	limit = GB(64) / PAGE_SIZE;
+#else
+	limit = MAXMEM / PAGE_SIZE;
+	if (!xen_initial_domain() && xen_512gb_limit)
+		limit = GB(512) / PAGE_SIZE;
+#endif
+	return limit;
+}
+
 static unsigned long __init xen_get_max_pages(void)
 {
-	unsigned long max_pages = MAX_DOMAIN_PAGES;
+	unsigned long max_pages, limit;
 	domid_t domid = DOMID_SELF;
 	int ret;
 
+	limit = xen_get_pages_limit();
+	max_pages = limit;
+
 	/*
 	 * For the initial domain we use the maximum reservation as
 	 * the maximum page.
@@ -532,7 +568,7 @@ static unsigned long __init xen_get_max_pages(void)
 			max_pages = ret;
 	}
 
-	return min(max_pages, MAX_DOMAIN_PAGES);
+	return min(max_pages, limit);
 }
 
 static void __init xen_align_and_add_e820_region(phys_addr_t start,
@@ -549,39 +585,188 @@ static void __init xen_align_and_add_e820_region(phys_addr_t start,
 	e820_add_region(start, end - start, type);
 }
 
-static void __init xen_ignore_unusable(struct e820entry *list, size_t map_size)
+static void __init xen_ignore_unusable(void)
 {
-	struct e820entry *entry;
+	struct e820entry *entry = xen_e820_map;
 	unsigned int i;
 
-	for (i = 0, entry = list; i < map_size; i++, entry++) {
+	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
 		if (entry->type == E820_UNUSABLE)
 			entry->type = E820_RAM;
 	}
 }
 
+static unsigned long __init xen_count_remap_pages(unsigned long max_pfn)
+{
+	unsigned long extra = 0;
+	unsigned long start_pfn, end_pfn;
+	const struct e820entry *entry = xen_e820_map;
+	int i;
+
+	end_pfn = 0;
+	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
+		start_pfn = PFN_DOWN(entry->addr);
+		/* Adjacent regions on non-page boundaries handling! */
+		end_pfn = min(end_pfn, start_pfn);
+
+		if (start_pfn >= max_pfn)
+			return extra + max_pfn - end_pfn;
+
+		/* Add any holes in map to result. */
+		extra += start_pfn - end_pfn;
+
+		end_pfn = PFN_UP(entry->addr + entry->size);
+		end_pfn = min(end_pfn, max_pfn);
+
+		if (entry->type != E820_RAM)
+			extra += end_pfn - start_pfn;
+	}
+
+	return extra;
+}
+
+bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size)
+{
+	struct e820entry *entry;
+	unsigned mapcnt;
+	phys_addr_t end;
+
+	if (!size)
+		return false;
+
+	end = start + size;
+	entry = xen_e820_map;
+
+	for (mapcnt = 0; mapcnt < xen_e820_map_entries; mapcnt++) {
+		if (entry->type == E820_RAM && entry->addr <= start &&
+		    (entry->addr + entry->size) >= end)
+			return false;
+
+		entry++;
+	}
+
+	return true;
+}
+
+/*
+ * Find a free area in physical memory not yet reserved and compliant with
+ * E820 map.
+ * Used to relocate pre-allocated areas like initrd or p2m list which are in
+ * conflict with the to be used E820 map.
+ * In case no area is found, return 0. Otherwise return the physical address
+ * of the area which is already reserved for convenience.
+ */
+phys_addr_t __init xen_find_free_area(phys_addr_t size)
+{
+	unsigned mapcnt;
+	phys_addr_t addr, start;
+	struct e820entry *entry = xen_e820_map;
+
+	for (mapcnt = 0; mapcnt < xen_e820_map_entries; mapcnt++, entry++) {
+		if (entry->type != E820_RAM || entry->size < size)
+			continue;
+		start = entry->addr;
+		for (addr = start; addr < start + size; addr += PAGE_SIZE) {
+			if (!memblock_is_reserved(addr))
+				continue;
+			start = addr + PAGE_SIZE;
+			if (start + size > entry->addr + entry->size)
+				break;
+		}
+		if (addr >= start + size) {
+			memblock_reserve(start, size);
+			return start;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * Like memcpy, but with physical addresses for dest and src.
+ */
+static void __init xen_phys_memcpy(phys_addr_t dest, phys_addr_t src,
+				   phys_addr_t n)
+{
+	phys_addr_t dest_off, src_off, dest_len, src_len, len;
+	void *from, *to;
+
+	while (n) {
+		dest_off = dest & ~PAGE_MASK;
+		src_off = src & ~PAGE_MASK;
+		dest_len = n;
+		if (dest_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off)
+			dest_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - dest_off;
+		src_len = n;
+		if (src_len > (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off)
+			src_len = (NR_FIX_BTMAPS << PAGE_SHIFT) - src_off;
+		len = min(dest_len, src_len);
+		to = early_memremap(dest - dest_off, dest_len + dest_off);
+		from = early_memremap(src - src_off, src_len + src_off);
+		memcpy(to, from, len);
+		early_memunmap(to, dest_len + dest_off);
+		early_memunmap(from, src_len + src_off);
+		n -= len;
+		dest += len;
+		src += len;
+	}
+}
+
+/*
+ * Reserve Xen mfn_list.
+ */
+static void __init xen_reserve_xen_mfnlist(void)
+{
+	phys_addr_t start, size;
+
+	if (xen_start_info->mfn_list >= __START_KERNEL_map) {
+		start = __pa(xen_start_info->mfn_list);
+		size = PFN_ALIGN(xen_start_info->nr_pages *
+				 sizeof(unsigned long));
+	} else {
+		start = PFN_PHYS(xen_start_info->first_p2m_pfn);
+		size = PFN_PHYS(xen_start_info->nr_p2m_frames);
+	}
+
+	if (!xen_is_e820_reserved(start, size)) {
+		memblock_reserve(start, size);
+		return;
+	}
+
+#ifdef CONFIG_X86_32
+	/*
+	 * Relocating the p2m on 32 bit system to an arbitrary virtual address
+	 * is not supported, so just give up.
+	 */
+	xen_raw_console_write("Xen hypervisor allocated p2m list conflicts with E820 map\n");
+	BUG();
+#else
+	xen_relocate_p2m();
+#endif
+}
+
 /**
  * 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;
-	phys_addr_t mem_end;
+	unsigned long max_pfn, pfn_s, n_pfns;
+	phys_addr_t mem_end, addr, size, chunk_size;
+	u32 type;
 	int rc;
 	struct xen_memory_map memmap;
 	unsigned long max_pages;
 	unsigned long extra_pages = 0;
-	unsigned long remapped_pages;
 	int i;
 	int op;
 
-	max_pfn = min(MAX_DOMAIN_PAGES, max_pfn);
+	xen_parse_512gb();
+	max_pfn = xen_get_pages_limit();
+	max_pfn = min(max_pfn, xen_start_info->nr_pages);
 	mem_end = PFN_PHYS(max_pfn);
 
 	memmap.nr_entries = E820MAX;
-	set_xen_guest_handle(memmap.buffer, map);
+	set_xen_guest_handle(memmap.buffer, xen_e820_map);
 
 	op = xen_initial_domain() ?
 		XENMEM_machine_memory_map :
@@ -590,15 +775,16 @@ char * __init xen_memory_setup(void)
 	if (rc == -ENOSYS) {
 		BUG_ON(xen_initial_domain());
 		memmap.nr_entries = 1;
-		map[0].addr = 0ULL;
-		map[0].size = mem_end;
+		xen_e820_map[0].addr = 0ULL;
+		xen_e820_map[0].size = mem_end;
 		/* 8MB slack (to balance backend allocations). */
-		map[0].size += 8ULL << 20;
-		map[0].type = E820_RAM;
+		xen_e820_map[0].size += 8ULL << 20;
+		xen_e820_map[0].type = E820_RAM;
 		rc = 0;
 	}
 	BUG_ON(rc);
 	BUG_ON(memmap.nr_entries == 0);
+	xen_e820_map_entries = memmap.nr_entries;
 
 	/*
 	 * Xen won't allow a 1:1 mapping to be created to UNUSABLE
@@ -609,24 +795,19 @@ char * __init xen_memory_setup(void)
 	 * a patch in the future.
 	 */
 	if (xen_initial_domain())
-		xen_ignore_unusable(map, memmap.nr_entries);
+		xen_ignore_unusable();
 
 	/* Make sure the Xen-supplied memory map is well-ordered. */
-	sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
+	sanitize_e820_map(xen_e820_map, xen_e820_map_entries,
+			  &xen_e820_map_entries);
 
 	max_pages = xen_get_max_pages();
-	if (max_pages > max_pfn)
-		extra_pages += max_pages - max_pfn;
 
-	/*
-	 * Set identity map on non-RAM pages and prepare remapping the
-	 * underlying RAM.
-	 */
-	xen_set_identity_and_remap(map, memmap.nr_entries, max_pfn,
-				   &xen_released_pages, &remapped_pages);
+	/* How many extra pages do we need due to remapping? */
+	max_pages += xen_count_remap_pages(max_pfn);
 
-	extra_pages += xen_released_pages;
-	extra_pages += remapped_pages;
+	if (max_pages > max_pfn)
+		extra_pages += max_pages - max_pfn;
 
 	/*
 	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
@@ -635,46 +816,54 @@ char * __init xen_memory_setup(void)
 	 * is limited to the max size of lowmem, so that it doesn't
 	 * get completely filled.
 	 *
+	 * Make sure we have no memory above max_pages, as this area
+	 * isn't handled by the p2m management.
+	 *
 	 * 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_pages = min(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
-			  extra_pages);
+	extra_pages = min3(EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM)),
+			   extra_pages, max_pages - max_pfn);
 	i = 0;
-	while (i < memmap.nr_entries) {
-		phys_addr_t addr = map[i].addr;
-		phys_addr_t size = map[i].size;
-		u32 type = map[i].type;
+	addr = xen_e820_map[0].addr;
+	size = xen_e820_map[0].size;
+	while (i < xen_e820_map_entries) {
+		chunk_size = size;
+		type = xen_e820_map[i].type;
 
 		if (type == E820_RAM) {
 			if (addr < mem_end) {
-				size = min(size, mem_end - addr);
+				chunk_size = min(size, mem_end - addr);
 			} else if (extra_pages) {
-				size = min(size, PFN_PHYS(extra_pages));
-				extra_pages -= PFN_DOWN(size);
-				xen_add_extra_mem(addr, size);
-				xen_max_p2m_pfn = PFN_DOWN(addr + size);
+				chunk_size = min(size, PFN_PHYS(extra_pages));
+				pfn_s = PFN_UP(addr);
+				n_pfns = PFN_DOWN(addr + chunk_size) - pfn_s;
+				extra_pages -= n_pfns;
+				xen_add_extra_mem(pfn_s, n_pfns);
+				xen_max_p2m_pfn = pfn_s + n_pfns;
 			} else
 				type = E820_UNUSABLE;
 		}
 
-		xen_align_and_add_e820_region(addr, size, type);
+		xen_align_and_add_e820_region(addr, chunk_size, type);
 
-		map[i].addr += size;
-		map[i].size -= size;
-		if (map[i].size == 0)
+		addr += chunk_size;
+		size -= chunk_size;
+		if (size == 0) {
 			i++;
+			if (i < xen_e820_map_entries) {
+				addr = xen_e820_map[i].addr;
+				size = xen_e820_map[i].size;
+			}
+		}
 	}
 
 	/*
 	 * Set the rest as identity mapped, in case PCI BARs are
 	 * located here.
-	 *
-	 * PFNs above MAX_P2M_PFN are considered identity mapped as
-	 * well.
 	 */
-	set_phys_range_identity(map[i-1].addr / PAGE_SIZE, ~0ul);
+	set_phys_range_identity(addr / PAGE_SIZE, ~0ul);
 
 	/*
 	 * In domU, the ISA region is normal, usable memory, but we
@@ -684,34 +873,53 @@ char * __init xen_memory_setup(void)
 	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 			E820_RESERVED);
 
+	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+
 	/*
-	 * Reserve Xen bits:
-	 *  - mfn_list
-	 *  - xen_start_info
-	 * See comment above "struct start_info" in <xen/interface/xen.h>
-	 * We tried to make the the memblock_reserve more selective so
-	 * that it would be clear what region is reserved. Sadly we ran
-	 * in the problem wherein on a 64-bit hypervisor with a 32-bit
-	 * initial domain, the pt_base has the cr3 value which is not
-	 * neccessarily where the pagetable starts! As Jan put it: "
-	 * Actually, the adjustment turns out to be correct: The page
-	 * tables for a 32-on-64 dom0 get allocated in the order "first L1",
-	 * "first L2", "first L3", so the offset to the page table base is
-	 * indeed 2. When reading xen/include/public/xen.h's comment
-	 * very strictly, this is not a violation (since there nothing is said
-	 * that the first thing in the page table space is pointed to by
-	 * pt_base; I admit that this seems to be implied though, namely
-	 * do I think that it is implied that the page table space is the
-	 * range [pt_base, pt_base + nt_pt_frames), whereas that
-	 * range here indeed is [pt_base - 2, pt_base - 2 + nt_pt_frames),
-	 * which - without a priori knowledge - the kernel would have
-	 * difficulty to figure out)." - so lets just fall back to the
-	 * easy way and reserve the whole region.
+	 * Check whether the kernel itself conflicts with the target E820 map.
+	 * Failing now is better than running into weird problems later due
+	 * to relocating (and even reusing) pages with kernel text or data.
 	 */
-	memblock_reserve(__pa(xen_start_info->mfn_list),
-			 xen_start_info->pt_base - xen_start_info->mfn_list);
+	if (xen_is_e820_reserved(__pa_symbol(_text),
+			__pa_symbol(__bss_stop) - __pa_symbol(_text))) {
+		xen_raw_console_write("Xen hypervisor allocated kernel memory conflicts with E820 map\n");
+		BUG();
+	}
 
-	sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
+	/*
+	 * Check for a conflict of the hypervisor supplied page tables with
+	 * the target E820 map.
+	 */
+	xen_pt_check_e820();
+
+	xen_reserve_xen_mfnlist();
+
+	/* Check for a conflict of the initrd with the target E820 map. */
+	if (xen_is_e820_reserved(boot_params.hdr.ramdisk_image,
+				 boot_params.hdr.ramdisk_size)) {
+		phys_addr_t new_area, start, size;
+
+		new_area = xen_find_free_area(boot_params.hdr.ramdisk_size);
+		if (!new_area) {
+			xen_raw_console_write("Can't find new memory area for initrd needed due to E820 map conflict\n");
+			BUG();
+		}
+
+		start = boot_params.hdr.ramdisk_image;
+		size = boot_params.hdr.ramdisk_size;
+		xen_phys_memcpy(new_area, start, size);
+		pr_info("initrd moved from [mem %#010llx-%#010llx] to [mem %#010llx-%#010llx]\n",
+			start, start + size, new_area, new_area + size);
+		memblock_free(start, size);
+		boot_params.hdr.ramdisk_image = new_area;
+		boot_params.ext_ramdisk_image = new_area >> 32;
+	}
+
+	/*
+	 * Set identity map on non-RAM pages and prepare remapping the
+	 * underlying RAM.
+	 */
+	xen_set_identity_and_remap(max_pfn);
 
 	return "Xen";
 }
@@ -721,26 +929,30 @@ char * __init xen_memory_setup(void)
  */
 char * __init xen_auto_xlated_memory_setup(void)
 {
-	static struct e820entry map[E820MAX] __initdata;
-
 	struct xen_memory_map memmap;
 	int i;
 	int rc;
 
 	memmap.nr_entries = E820MAX;
-	set_xen_guest_handle(memmap.buffer, map);
+	set_xen_guest_handle(memmap.buffer, xen_e820_map);
 
 	rc = HYPERVISOR_memory_op(XENMEM_memory_map, &memmap);
 	if (rc < 0)
 		panic("No memory map (%d)\n", rc);
 
-	sanitize_e820_map(map, ARRAY_SIZE(map), &memmap.nr_entries);
+	xen_e820_map_entries = memmap.nr_entries;
+
+	sanitize_e820_map(xen_e820_map, ARRAY_SIZE(xen_e820_map),
+			  &xen_e820_map_entries);
 
-	for (i = 0; i < memmap.nr_entries; i++)
-		e820_add_region(map[i].addr, map[i].size, map[i].type);
+	for (i = 0; i < xen_e820_map_entries; i++)
+		e820_add_region(xen_e820_map[i].addr, xen_e820_map[i].size,
+				xen_e820_map[i].type);
 
-	memblock_reserve(__pa(xen_start_info->mfn_list),
-			 xen_start_info->pt_base - xen_start_info->mfn_list);
+	/* Remove p2m info, it is not needed. */
+	xen_start_info->mfn_list = 0;
+	xen_start_info->first_p2m_pfn = 0;
+	xen_start_info->nr_p2m_frames = 0;
 
 	return "Xen";
 }
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 8648438..2a9ff73 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -26,6 +26,7 @@
 
 #include <xen/interface/xen.h>
 #include <xen/interface/vcpu.h>
+#include <xen/interface/xenpmu.h>
 
 #include <asm/xen/interface.h>
 #include <asm/xen/hypercall.h>
@@ -38,6 +39,7 @@
 #include "xen-ops.h"
 #include "mmu.h"
 #include "smp.h"
+#include "pmu.h"
 
 cpumask_var_t xen_cpu_initialized_map;
 
@@ -50,6 +52,7 @@ static DEFINE_PER_CPU(struct xen_common_irq, xen_callfunc_irq) = { .irq = -1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_callfuncsingle_irq) = { .irq = -1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };
 static DEFINE_PER_CPU(struct xen_common_irq, xen_debug_irq) = { .irq = -1 };
+static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };
 
 static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
 static irqreturn_t xen_call_function_single_interrupt(int irq, void *dev_id);
@@ -148,11 +151,18 @@ static void xen_smp_intr_free(unsigned int cpu)
 		kfree(per_cpu(xen_irq_work, cpu).name);
 		per_cpu(xen_irq_work, cpu).name = NULL;
 	}
+
+	if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {
+		unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);
+		per_cpu(xen_pmu_irq, cpu).irq = -1;
+		kfree(per_cpu(xen_pmu_irq, cpu).name);
+		per_cpu(xen_pmu_irq, cpu).name = NULL;
+	}
 };
 static int xen_smp_intr_init(unsigned int cpu)
 {
 	int rc;
-	char *resched_name, *callfunc_name, *debug_name;
+	char *resched_name, *callfunc_name, *debug_name, *pmu_name;
 
 	resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
 	rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
@@ -218,6 +228,18 @@ static int xen_smp_intr_init(unsigned int cpu)
 	per_cpu(xen_irq_work, cpu).irq = rc;
 	per_cpu(xen_irq_work, cpu).name = callfunc_name;
 
+	if (is_xen_pmu(cpu)) {
+		pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);
+		rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,
+					     xen_pmu_irq_handler,
+					     IRQF_PERCPU|IRQF_NOBALANCING,
+					     pmu_name, NULL);
+		if (rc < 0)
+			goto fail;
+		per_cpu(xen_pmu_irq, cpu).irq = rc;
+		per_cpu(xen_pmu_irq, cpu).name = pmu_name;
+	}
+
 	return 0;
 
  fail:
@@ -335,6 +357,8 @@ static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
 	}
 	set_cpu_sibling_map(0);
 
+	xen_pmu_init(0);
+
 	if (xen_smp_intr_init(0))
 		BUG();
 
@@ -462,6 +486,8 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle)
 	if (rc)
 		return rc;
 
+	xen_pmu_init(cpu);
+
 	rc = xen_smp_intr_init(cpu);
 	if (rc)
 		return rc;
@@ -503,6 +529,7 @@ static void xen_cpu_die(unsigned int cpu)
 		xen_smp_intr_free(cpu);
 		xen_uninit_lock_cpu(cpu);
 		xen_teardown_timer(cpu);
+		xen_pmu_finish(cpu);
 	}
 }
 
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 53b4c08..feddabd 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -11,6 +11,7 @@
 
 #include "xen-ops.h"
 #include "mmu.h"
+#include "pmu.h"
 
 static void xen_pv_pre_suspend(void)
 {
@@ -67,16 +68,26 @@ static void xen_pv_post_suspend(int suspend_cancelled)
 
 void xen_arch_pre_suspend(void)
 {
-    if (xen_pv_domain())
-        xen_pv_pre_suspend();
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		xen_pmu_finish(cpu);
+
+	if (xen_pv_domain())
+		xen_pv_pre_suspend();
 }
 
 void xen_arch_post_suspend(int cancelled)
 {
-    if (xen_pv_domain())
-        xen_pv_post_suspend(cancelled);
-    else
-        xen_hvm_post_suspend(cancelled);
+	int cpu;
+
+	if (xen_pv_domain())
+		xen_pv_post_suspend(cancelled);
+	else
+		xen_hvm_post_suspend(cancelled);
+
+	for_each_online_cpu(cpu)
+		xen_pmu_init(cpu);
 }
 
 static void xen_vcpu_notify_restore(void *data)
diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S
index 8afdfcc..b65f59a 100644
--- a/arch/x86/xen/xen-head.S
+++ b/arch/x86/xen/xen-head.S
@@ -104,6 +104,8 @@ ENTRY(hypercall_page)
 	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __PAGE_OFFSET)
 #else
 	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      _ASM_PTR __START_KERNEL_map)
+	/* Map the p2m table to a 512GB-aligned user address. */
+	ELFNOTE(Xen, XEN_ELFNOTE_INIT_P2M,       .quad PGDIR_SIZE)
 #endif
 	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          _ASM_PTR startup_xen)
 	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, _ASM_PTR hypercall_page)
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 2292721..1399423 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -35,13 +35,20 @@ void xen_build_mfn_list_list(void);
 void xen_setup_machphys_mapping(void);
 void xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn);
 void xen_reserve_top(void);
+void __init xen_reserve_special_pages(void);
+void __init xen_pt_check_e820(void);
 
 void xen_mm_pin_all(void);
 void xen_mm_unpin_all(void);
+#ifdef CONFIG_X86_64
+void __init xen_relocate_p2m(void);
+#endif
 
+bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size);
 unsigned long __ref xen_chk_extra_mem(unsigned long pfn);
 void __init xen_inv_extra_mem(void);
 void __init xen_remap_memory(void);
+phys_addr_t __init xen_find_free_area(phys_addr_t size);
 char * __init xen_memory_setup(void);
 char * xen_auto_xlated_memory_setup(void);
 void __init xen_arch_setup(void);