Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1482 insertions, 0 deletions

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
new file mode 100644
index 000000000..8f1ff8dad
--- /dev/null
+++ b/arch/x86/xen/enlighten_pv.c
@@ -0,0 +1,1482 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Core of Xen paravirt_ops implementation.
+ *
+ * This file contains the xen_paravirt_ops structure itself, and the
+ * implementations for:
+ * - privileged instructions
+ * - interrupt flags
+ * - segment operations
+ * - booting and setup
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#include <linux/cpu.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+#include <linux/preempt.h>
+#include <linux/hardirq.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/start_kernel.h>
+#include <linux/sched.h>
+#include <linux/kprobes.h>
+#include <linux/bootmem.h>
+#include <linux/export.h>
+#include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/highmem.h>
+#include <linux/console.h>
+#include <linux/pci.h>
+#include <linux/gfp.h>
+#include <linux/memblock.h>
+#include <linux/edd.h>
+#include <linux/frame.h>
+
+#include <xen/xen.h>
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/version.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/vcpu.h>
+#include <xen/interface/memory.h>
+#include <xen/interface/nmi.h>
+#include <xen/interface/xen-mca.h>
+#include <xen/features.h>
+#include <xen/page.h>
+#include <xen/hvc-console.h>
+#include <xen/acpi.h>
+
+#include <asm/paravirt.h>
+#include <asm/apic.h>
+#include <asm/page.h>
+#include <asm/xen/pci.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/cpuid.h>
+#include <asm/fixmap.h>
+#include <asm/processor.h>
+#include <asm/proto.h>
+#include <asm/msr-index.h>
+#include <asm/traps.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/reboot.h>
+#include <asm/stackprotector.h>
+#include <asm/hypervisor.h>
+#include <asm/mach_traps.h>
+#include <asm/mwait.h>
+#include <asm/pci_x86.h>
+#include <asm/cpu.h>
+
+#ifdef CONFIG_ACPI
+#include <linux/acpi.h>
+#include <asm/acpi.h>
+#include <acpi/pdc_intel.h>
+#include <acpi/processor.h>
+#include <xen/interface/platform.h>
+#endif
+
+#include "xen-ops.h"
+#include "mmu.h"
+#include "smp.h"
+#include "multicalls.h"
+#include "pmu.h"
+
+#include "../kernel/cpu/cpu.h" /* get_cpu_cap() */
+
+void *xen_initial_gdt;
+
+static int xen_cpu_up_prepare_pv(unsigned int cpu);
+static int xen_cpu_dead_pv(unsigned int cpu);
+
+struct tls_descs {
+	struct desc_struct desc[3];
+};
+
+/*
+ * Updating the 3 TLS descriptors in the GDT on every task switch is
+ * surprisingly expensive so we avoid updating them if they haven't
+ * changed.  Since Xen writes different descriptors than the one
+ * passed in the update_descriptor hypercall we keep shadow copies to
+ * compare against.
+ */
+static DEFINE_PER_CPU(struct tls_descs, shadow_tls_desc);
+
+static void __init xen_banner(void)
+{
+	unsigned version = HYPERVISOR_xen_version(XENVER_version, NULL);
+	struct xen_extraversion extra;
+	HYPERVISOR_xen_version(XENVER_extraversion, &extra);
+
+	pr_info("Booting paravirtualized kernel on %s\n", pv_info.name);
+	printk(KERN_INFO "Xen version: %d.%d%s%s\n",
+	       version >> 16, version & 0xffff, extra.extraversion,
+	       xen_feature(XENFEAT_mmu_pt_update_preserve_ad) ? " (preserve-AD)" : "");
+}
+
+static void __init xen_pv_init_platform(void)
+{
+	populate_extra_pte(fix_to_virt(FIX_PARAVIRT_BOOTMAP));
+
+	set_fixmap(FIX_PARAVIRT_BOOTMAP, xen_start_info->shared_info);
+	HYPERVISOR_shared_info = (void *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
+
+	/* xen clock uses per-cpu vcpu_info, need to init it for boot cpu */
+	xen_vcpu_info_reset(0);
+
+	/* pvclock is in shared info area */
+	xen_init_time_ops();
+}
+
+static void __init xen_pv_guest_late_init(void)
+{
+#ifndef CONFIG_SMP
+	/* Setup shared vcpu info for non-smp configurations */
+	xen_setup_vcpu_info_placement();
+#endif
+}
+
+/* Check if running on Xen version (major, minor) or later */
+bool
+xen_running_on_version_or_later(unsigned int major, unsigned int minor)
+{
+	unsigned int version;
+
+	if (!xen_domain())
+		return false;
+
+	version = HYPERVISOR_xen_version(XENVER_version, NULL);
+	if ((((version >> 16) == major) && ((version & 0xffff) >= minor)) ||
+		((version >> 16) > major))
+		return true;
+	return false;
+}
+
+static __read_mostly unsigned int cpuid_leaf5_ecx_val;
+static __read_mostly unsigned int cpuid_leaf5_edx_val;
+
+static void xen_cpuid(unsigned int *ax, unsigned int *bx,
+		      unsigned int *cx, unsigned int *dx)
+{
+	unsigned maskebx = ~0;
+
+	/*
+	 * Mask out inconvenient features, to try and disable as many
+	 * unsupported kernel subsystems as possible.
+	 */
+	switch (*ax) {
+	case CPUID_MWAIT_LEAF:
+		/* Synthesize the values.. */
+		*ax = 0;
+		*bx = 0;
+		*cx = cpuid_leaf5_ecx_val;
+		*dx = cpuid_leaf5_edx_val;
+		return;
+
+	case 0xb:
+		/* Suppress extended topology stuff */
+		maskebx = 0;
+		break;
+	}
+
+	asm(XEN_EMULATE_PREFIX "cpuid"
+		: "=a" (*ax),
+		  "=b" (*bx),
+		  "=c" (*cx),
+		  "=d" (*dx)
+		: "0" (*ax), "2" (*cx));
+
+	*bx &= maskebx;
+}
+STACK_FRAME_NON_STANDARD(xen_cpuid); /* XEN_EMULATE_PREFIX */
+
+static bool __init xen_check_mwait(void)
+{
+#ifdef CONFIG_ACPI
+	struct xen_platform_op op = {
+		.cmd			= XENPF_set_processor_pminfo,
+		.u.set_pminfo.id	= -1,
+		.u.set_pminfo.type	= XEN_PM_PDC,
+	};
+	uint32_t buf[3];
+	unsigned int ax, bx, cx, dx;
+	unsigned int mwait_mask;
+
+	/* We need to determine whether it is OK to expose the MWAIT
+	 * capability to the kernel to harvest deeper than C3 states from ACPI
+	 * _CST using the processor_harvest_xen.c module. For this to work, we
+	 * need to gather the MWAIT_LEAF values (which the cstate.c code
+	 * checks against). The hypervisor won't expose the MWAIT flag because
+	 * it would break backwards compatibility; so we will find out directly
+	 * from the hardware and hypercall.
+	 */
+	if (!xen_initial_domain())
+		return false;
+
+	/*
+	 * When running under platform earlier than Xen4.2, do not expose
+	 * mwait, to avoid the risk of loading native acpi pad driver
+	 */
+	if (!xen_running_on_version_or_later(4, 2))
+		return false;
+
+	ax = 1;
+	cx = 0;
+
+	native_cpuid(&ax, &bx, &cx, &dx);
+
+	mwait_mask = (1 << (X86_FEATURE_EST % 32)) |
+		     (1 << (X86_FEATURE_MWAIT % 32));
+
+	if ((cx & mwait_mask) != mwait_mask)
+		return false;
+
+	/* We need to emulate the MWAIT_LEAF and for that we need both
+	 * ecx and edx. The hypercall provides only partial information.
+	 */
+
+	ax = CPUID_MWAIT_LEAF;
+	bx = 0;
+	cx = 0;
+	dx = 0;
+
+	native_cpuid(&ax, &bx, &cx, &dx);
+
+	/* Ask the Hypervisor whether to clear ACPI_PDC_C_C2C3_FFH. If so,
+	 * don't expose MWAIT_LEAF and let ACPI pick the IOPORT version of C3.
+	 */
+	buf[0] = ACPI_PDC_REVISION_ID;
+	buf[1] = 1;
+	buf[2] = (ACPI_PDC_C_CAPABILITY_SMP | ACPI_PDC_EST_CAPABILITY_SWSMP);
+
+	set_xen_guest_handle(op.u.set_pminfo.pdc, buf);
+
+	if ((HYPERVISOR_platform_op(&op) == 0) &&
+	    (buf[2] & (ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH))) {
+		cpuid_leaf5_ecx_val = cx;
+		cpuid_leaf5_edx_val = dx;
+	}
+	return true;
+#else
+	return false;
+#endif
+}
+
+static bool __init xen_check_xsave(void)
+{
+	unsigned int cx, xsave_mask;
+
+	cx = cpuid_ecx(1);
+
+	xsave_mask = (1 << (X86_FEATURE_XSAVE % 32)) |
+		     (1 << (X86_FEATURE_OSXSAVE % 32));
+
+	/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
+	return (cx & xsave_mask) == xsave_mask;
+}
+
+static void __init xen_init_capabilities(void)
+{
+	setup_force_cpu_cap(X86_FEATURE_XENPV);
+	setup_clear_cpu_cap(X86_FEATURE_DCA);
+	setup_clear_cpu_cap(X86_FEATURE_APERFMPERF);
+	setup_clear_cpu_cap(X86_FEATURE_MTRR);
+	setup_clear_cpu_cap(X86_FEATURE_ACC);
+	setup_clear_cpu_cap(X86_FEATURE_X2APIC);
+	setup_clear_cpu_cap(X86_FEATURE_SME);
+
+	/*
+	 * Xen PV would need some work to support PCID: CR3 handling as well
+	 * as xen_flush_tlb_others() would need updating.
+	 */
+	setup_clear_cpu_cap(X86_FEATURE_PCID);
+
+	if (!xen_initial_domain())
+		setup_clear_cpu_cap(X86_FEATURE_ACPI);
+
+	if (xen_check_mwait())
+		setup_force_cpu_cap(X86_FEATURE_MWAIT);
+	else
+		setup_clear_cpu_cap(X86_FEATURE_MWAIT);
+
+	if (!xen_check_xsave()) {
+		setup_clear_cpu_cap(X86_FEATURE_XSAVE);
+		setup_clear_cpu_cap(X86_FEATURE_OSXSAVE);
+	}
+}
+
+static void xen_set_debugreg(int reg, unsigned long val)
+{
+	HYPERVISOR_set_debugreg(reg, val);
+}
+
+static unsigned long xen_get_debugreg(int reg)
+{
+	return HYPERVISOR_get_debugreg(reg);
+}
+
+static void xen_end_context_switch(struct task_struct *next)
+{
+	xen_mc_flush();
+	paravirt_end_context_switch(next);
+}
+
+static unsigned long xen_store_tr(void)
+{
+	return 0;
+}
+
+/*
+ * Set the page permissions for a particular virtual address.  If the
+ * address is a vmalloc mapping (or other non-linear mapping), then
+ * find the linear mapping of the page and also set its protections to
+ * match.
+ */
+static void set_aliased_prot(void *v, pgprot_t prot)
+{
+	int level;
+	pte_t *ptep;
+	pte_t pte;
+	unsigned long pfn;
+	struct page *page;
+	unsigned char dummy;
+
+	ptep = lookup_address((unsigned long)v, &level);
+	BUG_ON(ptep == NULL);
+
+	pfn = pte_pfn(*ptep);
+	page = pfn_to_page(pfn);
+
+	pte = pfn_pte(pfn, prot);
+
+	/*
+	 * Careful: update_va_mapping() will fail if the virtual address
+	 * we're poking isn't populated in the page tables.  We don't
+	 * need to worry about the direct map (that's always in the page
+	 * tables), but we need to be careful about vmap space.  In
+	 * particular, the top level page table can lazily propagate
+	 * entries between processes, so if we've switched mms since we
+	 * vmapped the target in the first place, we might not have the
+	 * top-level page table entry populated.
+	 *
+	 * We disable preemption because we want the same mm active when
+	 * we probe the target and when we issue the hypercall.  We'll
+	 * have the same nominal mm, but if we're a kernel thread, lazy
+	 * mm dropping could change our pgd.
+	 *
+	 * Out of an abundance of caution, this uses __get_user() to fault
+	 * in the target address just in case there's some obscure case
+	 * in which the target address isn't readable.
+	 */
+
+	preempt_disable();
+
+	probe_kernel_read(&dummy, v, 1);
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)v, pte, 0))
+		BUG();
+
+	if (!PageHighMem(page)) {
+		void *av = __va(PFN_PHYS(pfn));
+
+		if (av != v)
+			if (HYPERVISOR_update_va_mapping((unsigned long)av, pte, 0))
+				BUG();
+	} else
+		kmap_flush_unused();
+
+	preempt_enable();
+}
+
+static void xen_alloc_ldt(struct desc_struct *ldt, unsigned entries)
+{
+	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
+	int i;
+
+	/*
+	 * We need to mark the all aliases of the LDT pages RO.  We
+	 * don't need to call vm_flush_aliases(), though, since that's
+	 * only responsible for flushing aliases out the TLBs, not the
+	 * page tables, and Xen will flush the TLB for us if needed.
+	 *
+	 * To avoid confusing future readers: none of this is necessary
+	 * to load the LDT.  The hypervisor only checks this when the
+	 * LDT is faulted in due to subsequent descriptor access.
+	 */
+
+	for (i = 0; i < entries; i += entries_per_page)
+		set_aliased_prot(ldt + i, PAGE_KERNEL_RO);
+}
+
+static void xen_free_ldt(struct desc_struct *ldt, unsigned entries)
+{
+	const unsigned entries_per_page = PAGE_SIZE / LDT_ENTRY_SIZE;
+	int i;
+
+	for (i = 0; i < entries; i += entries_per_page)
+		set_aliased_prot(ldt + i, PAGE_KERNEL);
+}
+
+static void xen_set_ldt(const void *addr, unsigned entries)
+{
+	struct mmuext_op *op;
+	struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+	trace_xen_cpu_set_ldt(addr, entries);
+
+	op = mcs.args;
+	op->cmd = MMUEXT_SET_LDT;
+	op->arg1.linear_addr = (unsigned long)addr;
+	op->arg2.nr_ents = entries;
+
+	MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void xen_load_gdt(const struct desc_ptr *dtr)
+{
+	unsigned long va = dtr->address;
+	unsigned int size = dtr->size + 1;
+	unsigned long pfn, mfn;
+	int level;
+	pte_t *ptep;
+	void *virt;
+
+	/* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
+	BUG_ON(size > PAGE_SIZE);
+	BUG_ON(va & ~PAGE_MASK);
+
+	/*
+	 * The GDT is per-cpu and is in the percpu data area.
+	 * That can be virtually mapped, so we need to do a
+	 * page-walk to get the underlying MFN for the
+	 * hypercall.  The page can also be in the kernel's
+	 * linear range, so we need to RO that mapping too.
+	 */
+	ptep = lookup_address(va, &level);
+	BUG_ON(ptep == NULL);
+
+	pfn = pte_pfn(*ptep);
+	mfn = pfn_to_mfn(pfn);
+	virt = __va(PFN_PHYS(pfn));
+
+	make_lowmem_page_readonly((void *)va);
+	make_lowmem_page_readonly(virt);
+
+	if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
+		BUG();
+}
+
+/*
+ * load_gdt for early boot, when the gdt is only mapped once
+ */
+static void __init xen_load_gdt_boot(const struct desc_ptr *dtr)
+{
+	unsigned long va = dtr->address;
+	unsigned int size = dtr->size + 1;
+	unsigned long pfn, mfn;
+	pte_t pte;
+
+	/* @size should be at most GDT_SIZE which is smaller than PAGE_SIZE. */
+	BUG_ON(size > PAGE_SIZE);
+	BUG_ON(va & ~PAGE_MASK);
+
+	pfn = virt_to_pfn(va);
+	mfn = pfn_to_mfn(pfn);
+
+	pte = pfn_pte(pfn, PAGE_KERNEL_RO);
+
+	if (HYPERVISOR_update_va_mapping((unsigned long)va, pte, 0))
+		BUG();
+
+	if (HYPERVISOR_set_gdt(&mfn, size / sizeof(struct desc_struct)))
+		BUG();
+}
+
+static inline bool desc_equal(const struct desc_struct *d1,
+			      const struct desc_struct *d2)
+{
+	return !memcmp(d1, d2, sizeof(*d1));
+}
+
+static void load_TLS_descriptor(struct thread_struct *t,
+				unsigned int cpu, unsigned int i)
+{
+	struct desc_struct *shadow = &per_cpu(shadow_tls_desc, cpu).desc[i];
+	struct desc_struct *gdt;
+	xmaddr_t maddr;
+	struct multicall_space mc;
+
+	if (desc_equal(shadow, &t->tls_array[i]))
+		return;
+
+	*shadow = t->tls_array[i];
+
+	gdt = get_cpu_gdt_rw(cpu);
+	maddr = arbitrary_virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
+	mc = __xen_mc_entry(0);
+
+	MULTI_update_descriptor(mc.mc, maddr.maddr, t->tls_array[i]);
+}
+
+static void xen_load_tls(struct thread_struct *t, unsigned int cpu)
+{
+	/*
+	 * XXX sleazy hack: If we're being called in a lazy-cpu zone
+	 * and lazy gs handling is enabled, it means we're in a
+	 * context switch, and %gs has just been saved.  This means we
+	 * can zero it out to prevent faults on exit from the
+	 * hypervisor if the next process has no %gs.  Either way, it
+	 * has been saved, and the new value will get loaded properly.
+	 * This will go away as soon as Xen has been modified to not
+	 * save/restore %gs for normal hypercalls.
+	 *
+	 * On x86_64, this hack is not used for %gs, because gs points
+	 * to KERNEL_GS_BASE (and uses it for PDA references), so we
+	 * must not zero %gs on x86_64
+	 *
+	 * For x86_64, we need to zero %fs, otherwise we may get an
+	 * exception between the new %fs descriptor being loaded and
+	 * %fs being effectively cleared at __switch_to().
+	 */
+	if (paravirt_get_lazy_mode() == PARAVIRT_LAZY_CPU) {
+#ifdef CONFIG_X86_32
+		lazy_load_gs(0);
+#else
+		loadsegment(fs, 0);
+#endif
+	}
+
+	xen_mc_batch();
+
+	load_TLS_descriptor(t, cpu, 0);
+	load_TLS_descriptor(t, cpu, 1);
+	load_TLS_descriptor(t, cpu, 2);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+#ifdef CONFIG_X86_64
+static void xen_load_gs_index(unsigned int idx)
+{
+	if (HYPERVISOR_set_segment_base(SEGBASE_GS_USER_SEL, idx))
+		BUG();
+}
+#endif
+
+static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
+				const void *ptr)
+{
+	xmaddr_t mach_lp = arbitrary_virt_to_machine(&dt[entrynum]);
+	u64 entry = *(u64 *)ptr;
+
+	trace_xen_cpu_write_ldt_entry(dt, entrynum, entry);
+
+	preempt_disable();
+
+	xen_mc_flush();
+	if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
+		BUG();
+
+	preempt_enable();
+}
+
+#ifdef CONFIG_X86_64
+struct trap_array_entry {
+	void (*orig)(void);
+	void (*xen)(void);
+	bool ist_okay;
+};
+
+static struct trap_array_entry trap_array[] = {
+	{ debug,                       xen_xendebug,                    true },
+	{ double_fault,                xen_double_fault,                true },
+#ifdef CONFIG_X86_MCE
+	{ machine_check,               xen_machine_check,               true },
+#endif
+	{ nmi,                         xen_xennmi,                      true },
+	{ int3,                        xen_int3,                        false },
+	{ overflow,                    xen_overflow,                    false },
+#ifdef CONFIG_IA32_EMULATION
+	{ entry_INT80_compat,          xen_entry_INT80_compat,          false },
+#endif
+	{ page_fault,                  xen_page_fault,                  false },
+	{ divide_error,                xen_divide_error,                false },
+	{ bounds,                      xen_bounds,                      false },
+	{ invalid_op,                  xen_invalid_op,                  false },
+	{ device_not_available,        xen_device_not_available,        false },
+	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
+	{ invalid_TSS,                 xen_invalid_TSS,                 false },
+	{ segment_not_present,         xen_segment_not_present,         false },
+	{ stack_segment,               xen_stack_segment,               false },
+	{ general_protection,          xen_general_protection,          false },
+	{ spurious_interrupt_bug,      xen_spurious_interrupt_bug,      false },
+	{ coprocessor_error,           xen_coprocessor_error,           false },
+	{ alignment_check,             xen_alignment_check,             false },
+	{ simd_coprocessor_error,      xen_simd_coprocessor_error,      false },
+};
+
+static bool __ref get_trap_addr(void **addr, unsigned int ist)
+{
+	unsigned int nr;
+	bool ist_okay = false;
+
+	/*
+	 * Replace trap handler addresses by Xen specific ones.
+	 * Check for known traps using IST and whitelist them.
+	 * The debugger ones are the only ones we care about.
+	 * Xen will handle faults like double_fault, * so we should never see
+	 * them.  Warn if there's an unexpected IST-using fault handler.
+	 */
+	for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
+		struct trap_array_entry *entry = trap_array + nr;
+
+		if (*addr == entry->orig) {
+			*addr = entry->xen;
+			ist_okay = entry->ist_okay;
+			break;
+		}
+	}
+
+	if (nr == ARRAY_SIZE(trap_array) &&
+	    *addr >= (void *)early_idt_handler_array[0] &&
+	    *addr < (void *)early_idt_handler_array[NUM_EXCEPTION_VECTORS]) {
+		nr = (*addr - (void *)early_idt_handler_array[0]) /
+		     EARLY_IDT_HANDLER_SIZE;
+		*addr = (void *)xen_early_idt_handler_array[nr];
+	}
+
+	if (WARN_ON(ist != 0 && !ist_okay))
+		return false;
+
+	return true;
+}
+#endif
+
+static int cvt_gate_to_trap(int vector, const gate_desc *val,
+			    struct trap_info *info)
+{
+	unsigned long addr;
+
+	if (val->bits.type != GATE_TRAP && val->bits.type != GATE_INTERRUPT)
+		return 0;
+
+	info->vector = vector;
+
+	addr = gate_offset(val);
+#ifdef CONFIG_X86_64
+	if (!get_trap_addr((void **)&addr, val->bits.ist))
+		return 0;
+#endif	/* CONFIG_X86_64 */
+	info->address = addr;
+
+	info->cs = gate_segment(val);
+	info->flags = val->bits.dpl;
+	/* interrupt gates clear IF */
+	if (val->bits.type == GATE_INTERRUPT)
+		info->flags |= 1 << 2;
+
+	return 1;
+}
+
+/* Locations of each CPU's IDT */
+static DEFINE_PER_CPU(struct desc_ptr, idt_desc);
+
+/* Set an IDT entry.  If the entry is part of the current IDT, then
+   also update Xen. */
+static void xen_write_idt_entry(gate_desc *dt, int entrynum, const gate_desc *g)
+{
+	unsigned long p = (unsigned long)&dt[entrynum];
+	unsigned long start, end;
+
+	trace_xen_cpu_write_idt_entry(dt, entrynum, g);
+
+	preempt_disable();
+
+	start = __this_cpu_read(idt_desc.address);
+	end = start + __this_cpu_read(idt_desc.size) + 1;
+
+	xen_mc_flush();
+
+	native_write_idt_entry(dt, entrynum, g);
+
+	if (p >= start && (p + 8) <= end) {
+		struct trap_info info[2];
+
+		info[1].address = 0;
+
+		if (cvt_gate_to_trap(entrynum, g, &info[0]))
+			if (HYPERVISOR_set_trap_table(info))
+				BUG();
+	}
+
+	preempt_enable();
+}
+
+static unsigned xen_convert_trap_info(const struct desc_ptr *desc,
+				      struct trap_info *traps, bool full)
+{
+	unsigned in, out, count;
+
+	count = (desc->size+1) / sizeof(gate_desc);
+	BUG_ON(count > 256);
+
+	for (in = out = 0; in < count; in++) {
+		gate_desc *entry = (gate_desc *)(desc->address) + in;
+
+		if (cvt_gate_to_trap(in, entry, &traps[out]) || full)
+			out++;
+	}
+
+	return out;
+}
+
+void xen_copy_trap_info(struct trap_info *traps)
+{
+	const struct desc_ptr *desc = this_cpu_ptr(&idt_desc);
+
+	xen_convert_trap_info(desc, traps, true);
+}
+
+/* Load a new IDT into Xen.  In principle this can be per-CPU, so we
+   hold a spinlock to protect the static traps[] array (static because
+   it avoids allocation, and saves stack space). */
+static void xen_load_idt(const struct desc_ptr *desc)
+{
+	static DEFINE_SPINLOCK(lock);
+	static struct trap_info traps[257];
+	unsigned out;
+
+	trace_xen_cpu_load_idt(desc);
+
+	spin_lock(&lock);
+
+	memcpy(this_cpu_ptr(&idt_desc), desc, sizeof(idt_desc));
+
+	out = xen_convert_trap_info(desc, traps, false);
+	memset(&traps[out], 0, sizeof(traps[0]));
+
+	xen_mc_flush();
+	if (HYPERVISOR_set_trap_table(traps))
+		BUG();
+
+	spin_unlock(&lock);
+}
+
+/* Write a GDT descriptor entry.  Ignore LDT descriptors, since
+   they're handled differently. */
+static void xen_write_gdt_entry(struct desc_struct *dt, int entry,
+				const void *desc, int type)
+{
+	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
+
+	preempt_disable();
+
+	switch (type) {
+	case DESC_LDT:
+	case DESC_TSS:
+		/* ignore */
+		break;
+
+	default: {
+		xmaddr_t maddr = arbitrary_virt_to_machine(&dt[entry]);
+
+		xen_mc_flush();
+		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
+			BUG();
+	}
+
+	}
+
+	preempt_enable();
+}
+
+/*
+ * Version of write_gdt_entry for use at early boot-time needed to
+ * update an entry as simply as possible.
+ */
+static void __init xen_write_gdt_entry_boot(struct desc_struct *dt, int entry,
+					    const void *desc, int type)
+{
+	trace_xen_cpu_write_gdt_entry(dt, entry, desc, type);
+
+	switch (type) {
+	case DESC_LDT:
+	case DESC_TSS:
+		/* ignore */
+		break;
+
+	default: {
+		xmaddr_t maddr = virt_to_machine(&dt[entry]);
+
+		if (HYPERVISOR_update_descriptor(maddr.maddr, *(u64 *)desc))
+			dt[entry] = *(struct desc_struct *)desc;
+	}
+
+	}
+}
+
+static void xen_load_sp0(unsigned long sp0)
+{
+	struct multicall_space mcs;
+
+	mcs = xen_mc_entry(0);
+	MULTI_stack_switch(mcs.mc, __KERNEL_DS, sp0);
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+	this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0);
+}
+
+void xen_set_iopl_mask(unsigned mask)
+{
+	struct physdev_set_iopl set_iopl;
+
+	/* Force the change at ring 0. */
+	set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3;
+	HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+}
+
+static void xen_io_delay(void)
+{
+}
+
+static DEFINE_PER_CPU(unsigned long, xen_cr0_value);
+
+static unsigned long xen_read_cr0(void)
+{
+	unsigned long cr0 = this_cpu_read(xen_cr0_value);
+
+	if (unlikely(cr0 == 0)) {
+		cr0 = native_read_cr0();
+		this_cpu_write(xen_cr0_value, cr0);
+	}
+
+	return cr0;
+}
+
+static void xen_write_cr0(unsigned long cr0)
+{
+	struct multicall_space mcs;
+
+	this_cpu_write(xen_cr0_value, cr0);
+
+	/* Only pay attention to cr0.TS; everything else is
+	   ignored. */
+	mcs = xen_mc_entry(0);
+
+	MULTI_fpu_taskswitch(mcs.mc, (cr0 & X86_CR0_TS) != 0);
+
+	xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void xen_write_cr4(unsigned long cr4)
+{
+	cr4 &= ~(X86_CR4_PGE | X86_CR4_PSE | X86_CR4_PCE);
+
+	native_write_cr4(cr4);
+}
+#ifdef CONFIG_X86_64
+static inline unsigned long xen_read_cr8(void)
+{
+	return 0;
+}
+static inline void xen_write_cr8(unsigned long val)
+{
+	BUG_ON(val);
+}
+#endif
+
+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:
+		val &= ~X2APIC_ENABLE;
+		break;
+	}
+	return val;
+}
+
+static int xen_write_msr_safe(unsigned int msr, unsigned low, unsigned high)
+{
+	int ret;
+#ifdef CONFIG_X86_64
+	unsigned int which;
+	u64 base;
+#endif
+
+	ret = 0;
+
+	switch (msr) {
+#ifdef CONFIG_X86_64
+	case MSR_FS_BASE:		which = SEGBASE_FS; goto set;
+	case MSR_KERNEL_GS_BASE:	which = SEGBASE_GS_USER; goto set;
+	case MSR_GS_BASE:		which = SEGBASE_GS_KERNEL; goto set;
+
+	set:
+		base = ((u64)high << 32) | low;
+		if (HYPERVISOR_set_segment_base(which, base) != 0)
+			ret = -EIO;
+		break;
+#endif
+
+	case MSR_STAR:
+	case MSR_CSTAR:
+	case MSR_LSTAR:
+	case MSR_SYSCALL_MASK:
+	case MSR_IA32_SYSENTER_CS:
+	case MSR_IA32_SYSENTER_ESP:
+	case MSR_IA32_SYSENTER_EIP:
+		/* Fast syscall setup is all done in hypercalls, so
+		   these are all ignored.  Stub them out here to stop
+		   Xen console noise. */
+		break;
+
+	default:
+		if (!pmu_msr_write(msr, low, high, &ret))
+			ret = native_write_msr_safe(msr, low, high);
+	}
+
+	return ret;
+}
+
+static u64 xen_read_msr(unsigned int msr)
+{
+	/*
+	 * This will silently swallow a #GP from RDMSR.  It may be worth
+	 * changing that.
+	 */
+	int err;
+
+	return xen_read_msr_safe(msr, &err);
+}
+
+static void xen_write_msr(unsigned int msr, unsigned low, unsigned high)
+{
+	/*
+	 * This will silently swallow a #GP from WRMSR.  It may be worth
+	 * changing that.
+	 */
+	xen_write_msr_safe(msr, low, high);
+}
+
+/* This is called once we have the cpu_possible_mask */
+void __init xen_setup_vcpu_info_placement(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		/* Set up direct vCPU id mapping for PV guests. */
+		per_cpu(xen_vcpu_id, cpu) = cpu;
+
+		/*
+		 * xen_vcpu_setup(cpu) can fail  -- in which case it
+		 * falls back to the shared_info version for cpus
+		 * where xen_vcpu_nr(cpu) < MAX_VIRT_CPUS.
+		 *
+		 * xen_cpu_up_prepare_pv() handles the rest by failing
+		 * them in hotplug.
+		 */
+		(void) xen_vcpu_setup(cpu);
+	}
+
+	/*
+	 * xen_vcpu_setup managed to place the vcpu_info within the
+	 * percpu area for all cpus, so make use of it.
+	 */
+	if (xen_have_vcpu_info_placement) {
+		pv_irq_ops.save_fl = __PV_IS_CALLEE_SAVE(xen_save_fl_direct);
+		pv_irq_ops.restore_fl = __PV_IS_CALLEE_SAVE(xen_restore_fl_direct);
+		pv_irq_ops.irq_disable = __PV_IS_CALLEE_SAVE(xen_irq_disable_direct);
+		pv_irq_ops.irq_enable = __PV_IS_CALLEE_SAVE(xen_irq_enable_direct);
+		pv_mmu_ops.read_cr2 = xen_read_cr2_direct;
+	}
+}
+
+static const struct pv_info xen_info __initconst = {
+	.shared_kernel_pmd = 0,
+
+#ifdef CONFIG_X86_64
+	.extra_user_64bit_cs = FLAT_USER_CS64,
+#endif
+	.name = "Xen",
+};
+
+static const struct pv_cpu_ops xen_cpu_ops __initconst = {
+	.cpuid = xen_cpuid,
+
+	.set_debugreg = xen_set_debugreg,
+	.get_debugreg = xen_get_debugreg,
+
+	.read_cr0 = xen_read_cr0,
+	.write_cr0 = xen_write_cr0,
+
+	.write_cr4 = xen_write_cr4,
+
+#ifdef CONFIG_X86_64
+	.read_cr8 = xen_read_cr8,
+	.write_cr8 = xen_write_cr8,
+#endif
+
+	.wbinvd = native_wbinvd,
+
+	.read_msr = xen_read_msr,
+	.write_msr = xen_write_msr,
+
+	.read_msr_safe = xen_read_msr_safe,
+	.write_msr_safe = xen_write_msr_safe,
+
+	.read_pmc = xen_read_pmc,
+
+	.iret = xen_iret,
+#ifdef CONFIG_X86_64
+	.usergs_sysret64 = xen_sysret64,
+#endif
+
+	.load_tr_desc = paravirt_nop,
+	.set_ldt = xen_set_ldt,
+	.load_gdt = xen_load_gdt,
+	.load_idt = xen_load_idt,
+	.load_tls = xen_load_tls,
+#ifdef CONFIG_X86_64
+	.load_gs_index = xen_load_gs_index,
+#endif
+
+	.alloc_ldt = xen_alloc_ldt,
+	.free_ldt = xen_free_ldt,
+
+	.store_tr = xen_store_tr,
+
+	.write_ldt_entry = xen_write_ldt_entry,
+	.write_gdt_entry = xen_write_gdt_entry,
+	.write_idt_entry = xen_write_idt_entry,
+	.load_sp0 = xen_load_sp0,
+
+	.set_iopl_mask = xen_set_iopl_mask,
+	.io_delay = xen_io_delay,
+
+	/* Xen takes care of %gs when switching to usermode for us */
+	.swapgs = paravirt_nop,
+
+	.start_context_switch = paravirt_start_context_switch,
+	.end_context_switch = xen_end_context_switch,
+};
+
+static void xen_restart(char *msg)
+{
+	xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_machine_halt(void)
+{
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_machine_power_off(void)
+{
+	if (pm_power_off)
+		pm_power_off();
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_crash_shutdown(struct pt_regs *regs)
+{
+	xen_reboot(SHUTDOWN_crash);
+}
+
+static const struct machine_ops xen_machine_ops __initconst = {
+	.restart = xen_restart,
+	.halt = xen_machine_halt,
+	.power_off = xen_machine_power_off,
+	.shutdown = xen_machine_halt,
+	.crash_shutdown = xen_crash_shutdown,
+	.emergency_restart = xen_emergency_restart,
+};
+
+static unsigned char xen_get_nmi_reason(void)
+{
+	unsigned char reason = 0;
+
+	/* Construct a value which looks like it came from port 0x61. */
+	if (test_bit(_XEN_NMIREASON_io_error,
+		     &HYPERVISOR_shared_info->arch.nmi_reason))
+		reason |= NMI_REASON_IOCHK;
+	if (test_bit(_XEN_NMIREASON_pci_serr,
+		     &HYPERVISOR_shared_info->arch.nmi_reason))
+		reason |= NMI_REASON_SERR;
+
+	return reason;
+}
+
+static void __init xen_boot_params_init_edd(void)
+{
+#if IS_ENABLED(CONFIG_EDD)
+	struct xen_platform_op op;
+	struct edd_info *edd_info;
+	u32 *mbr_signature;
+	unsigned nr;
+	int ret;
+
+	edd_info = boot_params.eddbuf;
+	mbr_signature = boot_params.edd_mbr_sig_buffer;
+
+	op.cmd = XENPF_firmware_info;
+
+	op.u.firmware_info.type = XEN_FW_DISK_INFO;
+	for (nr = 0; nr < EDDMAXNR; nr++) {
+		struct edd_info *info = edd_info + nr;
+
+		op.u.firmware_info.index = nr;
+		info->params.length = sizeof(info->params);
+		set_xen_guest_handle(op.u.firmware_info.u.disk_info.edd_params,
+				     &info->params);
+		ret = HYPERVISOR_platform_op(&op);
+		if (ret)
+			break;
+
+#define C(x) info->x = op.u.firmware_info.u.disk_info.x
+		C(device);
+		C(version);
+		C(interface_support);
+		C(legacy_max_cylinder);
+		C(legacy_max_head);
+		C(legacy_sectors_per_track);
+#undef C
+	}
+	boot_params.eddbuf_entries = nr;
+
+	op.u.firmware_info.type = XEN_FW_DISK_MBR_SIGNATURE;
+	for (nr = 0; nr < EDD_MBR_SIG_MAX; nr++) {
+		op.u.firmware_info.index = nr;
+		ret = HYPERVISOR_platform_op(&op);
+		if (ret)
+			break;
+		mbr_signature[nr] = op.u.firmware_info.u.disk_mbr_signature.mbr_signature;
+	}
+	boot_params.edd_mbr_sig_buf_entries = nr;
+#endif
+}
+
+/*
+ * Set up the GDT and segment registers for -fstack-protector.  Until
+ * we do this, we have to be careful not to call any stack-protected
+ * function, which is most of the kernel.
+ */
+static void __init xen_setup_gdt(int cpu)
+{
+	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry_boot;
+	pv_cpu_ops.load_gdt = xen_load_gdt_boot;
+
+	setup_stack_canary_segment(cpu);
+	switch_to_new_gdt(cpu);
+
+	pv_cpu_ops.write_gdt_entry = xen_write_gdt_entry;
+	pv_cpu_ops.load_gdt = xen_load_gdt;
+}
+
+static void __init xen_dom0_set_legacy_features(void)
+{
+	x86_platform.legacy.rtc = 1;
+}
+
+static void __init xen_domu_set_legacy_features(void)
+{
+	x86_platform.legacy.rtc = 0;
+}
+
+/* First C function to be called on Xen boot */
+asmlinkage __visible void __init xen_start_kernel(void)
+{
+	struct physdev_set_iopl set_iopl;
+	unsigned long initrd_start = 0;
+	int rc;
+
+	if (!xen_start_info)
+		return;
+
+	xen_domain_type = XEN_PV_DOMAIN;
+	xen_start_flags = xen_start_info->flags;
+
+	xen_setup_features();
+
+	/* Install Xen paravirt ops */
+	pv_info = xen_info;
+	pv_init_ops.patch = paravirt_patch_default;
+	pv_cpu_ops = xen_cpu_ops;
+	xen_init_irq_ops();
+
+	/*
+	 * Setup xen_vcpu early because it is needed for
+	 * local_irq_disable(), irqs_disabled(), e.g. in printk().
+	 *
+	 * Don't do the full vcpu_info placement stuff until we have
+	 * the cpu_possible_mask and a non-dummy shared_info.
+	 */
+	xen_vcpu_info_reset(0);
+
+	x86_platform.get_nmi_reason = xen_get_nmi_reason;
+
+	x86_init.resources.memory_setup = xen_memory_setup;
+	x86_init.irqs.intr_mode_init	= x86_init_noop;
+	x86_init.oem.arch_setup = xen_arch_setup;
+	x86_init.oem.banner = xen_banner;
+	x86_init.hyper.init_platform = xen_pv_init_platform;
+	x86_init.hyper.guest_late_init = xen_pv_guest_late_init;
+
+	/*
+	 * Set up some pagetable state before starting to set any ptes.
+	 */
+
+	xen_setup_machphys_mapping();
+	xen_init_mmu_ops();
+
+	/* Prevent unwanted bits from being set in PTEs. */
+	__supported_pte_mask &= ~_PAGE_GLOBAL;
+	__default_kernel_pte_mask &= ~_PAGE_GLOBAL;
+
+	/*
+	 * Prevent page tables from being allocated in highmem, even
+	 * if CONFIG_HIGHPTE is enabled.
+	 */
+	__userpte_alloc_gfp &= ~__GFP_HIGHMEM;
+
+	/* Get mfn list */
+	xen_build_dynamic_phys_to_machine();
+
+	/*
+	 * Set up kernel GDT and segment registers, mainly so that
+	 * -fstack-protector code can be executed.
+	 */
+	xen_setup_gdt(0);
+
+	/* Work out if we support NX */
+	get_cpu_cap(&boot_cpu_data);
+	x86_configure_nx();
+
+	/* Determine virtual and physical address sizes */
+	get_cpu_address_sizes(&boot_cpu_data);
+
+	/* Let's presume PV guests always boot on vCPU with id 0. */
+	per_cpu(xen_vcpu_id, 0) = 0;
+
+	idt_setup_early_handler();
+
+	xen_init_capabilities();
+
+#ifdef CONFIG_X86_LOCAL_APIC
+	/*
+	 * set up the basic apic ops.
+	 */
+	xen_init_apic();
+#endif
+
+	if (xen_feature(XENFEAT_mmu_pt_update_preserve_ad)) {
+		pv_mmu_ops.ptep_modify_prot_start = xen_ptep_modify_prot_start;
+		pv_mmu_ops.ptep_modify_prot_commit = xen_ptep_modify_prot_commit;
+	}
+
+	machine_ops = xen_machine_ops;
+
+	/*
+	 * The only reliable way to retain the initial address of the
+	 * percpu gdt_page is to remember it here, so we can go and
+	 * mark it RW later, when the initial percpu area is freed.
+	 */
+	xen_initial_gdt = &per_cpu(gdt_page, 0);
+
+	xen_smp_init();
+
+#ifdef CONFIG_ACPI_NUMA
+	/*
+	 * The pages we from Xen are not related to machine pages, so
+	 * any NUMA information the kernel tries to get from ACPI will
+	 * be meaningless.  Prevent it from trying.
+	 */
+	acpi_numa = -1;
+#endif
+	WARN_ON(xen_cpuhp_setup(xen_cpu_up_prepare_pv, xen_cpu_dead_pv));
+
+	local_irq_disable();
+	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_reserve_special_pages();
+
+	/* keep using Xen gdt for now; no urgent need to change it */
+
+#ifdef CONFIG_X86_32
+	pv_info.kernel_rpl = 1;
+	if (xen_feature(XENFEAT_supervisor_mode_kernel))
+		pv_info.kernel_rpl = 0;
+#else
+	pv_info.kernel_rpl = 0;
+#endif
+	/* set the limit of our address space */
+	xen_reserve_top();
+
+	/*
+	 * We used to do this in xen_arch_setup, but that is too late
+	 * on AMD were early_cpu_init (run before ->arch_setup()) calls
+	 * early_amd_init which pokes 0xcf8 port.
+	 */
+	set_iopl.iopl = 1;
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+	if (rc != 0)
+		xen_raw_printk("physdev_op failed %d\n", rc);
+
+#ifdef CONFIG_X86_32
+	/* set up basic CPUID stuff */
+	cpu_detect(&new_cpu_data);
+	set_cpu_cap(&new_cpu_data, X86_FEATURE_FPU);
+	new_cpu_data.x86_capability[CPUID_1_EDX] = cpuid_edx(1);
+#endif
+
+	if (xen_start_info->mod_start) {
+	    if (xen_start_info->flags & SIF_MOD_START_PFN)
+		initrd_start = PFN_PHYS(xen_start_info->mod_start);
+	    else
+		initrd_start = __pa(xen_start_info->mod_start);
+	}
+
+	/* Poke various useful things into boot_params */
+	boot_params.hdr.type_of_loader = (9 << 4) | 0;
+	boot_params.hdr.ramdisk_image = initrd_start;
+	boot_params.hdr.ramdisk_size = xen_start_info->mod_len;
+	boot_params.hdr.cmd_line_ptr = __pa(xen_start_info->cmd_line);
+	boot_params.hdr.hardware_subarch = X86_SUBARCH_XEN;
+
+	if (!xen_initial_domain()) {
+		add_preferred_console("xenboot", 0, NULL);
+		if (pci_xen)
+			x86_init.pci.arch_init = pci_xen_init;
+		x86_platform.set_legacy_features =
+				xen_domu_set_legacy_features;
+	} else {
+		const struct dom0_vga_console_info *info =
+			(void *)((char *)xen_start_info +
+				 xen_start_info->console.dom0.info_off);
+		struct xen_platform_op op = {
+			.cmd = XENPF_firmware_info,
+			.interface_version = XENPF_INTERFACE_VERSION,
+			.u.firmware_info.type = XEN_FW_KBD_SHIFT_FLAGS,
+		};
+
+		x86_platform.set_legacy_features =
+				xen_dom0_set_legacy_features;
+		xen_init_vga(info, xen_start_info->console.dom0.info_size);
+		xen_start_info->console.domU.mfn = 0;
+		xen_start_info->console.domU.evtchn = 0;
+
+		if (HYPERVISOR_platform_op(&op) == 0)
+			boot_params.kbd_status = op.u.firmware_info.u.kbd_shift_flags;
+
+		/* Make sure ACS will be enabled */
+		pci_request_acs();
+
+		xen_acpi_sleep_register();
+
+		/* Avoid searching for BIOS MP tables */
+		x86_init.mpparse.find_smp_config = x86_init_noop;
+		x86_init.mpparse.get_smp_config = x86_init_uint_noop;
+
+		xen_boot_params_init_edd();
+
+#ifdef CONFIG_ACPI
+		/*
+		 * Disable selecting "Firmware First mode" for correctable
+		 * memory errors, as this is the duty of the hypervisor to
+		 * decide.
+		 */
+		acpi_disable_cmcff = 1;
+#endif
+	}
+
+	if (!boot_params.screen_info.orig_video_isVGA)
+		add_preferred_console("tty", 0, NULL);
+	add_preferred_console("hvc", 0, NULL);
+	if (boot_params.screen_info.orig_video_isVGA)
+		add_preferred_console("tty", 0, NULL);
+
+#ifdef CONFIG_PCI
+	/* PCI BIOS service won't work from a PV guest. */
+	pci_probe &= ~PCI_PROBE_BIOS;
+#endif
+	xen_raw_console_write("about to get started...\n");
+
+	/* We need this for printk timestamps */
+	xen_setup_runstate_info(0);
+
+	xen_efi_init(&boot_params);
+
+	/* Start the world */
+#ifdef CONFIG_X86_32
+	i386_start_kernel();
+#else
+	cr4_init_shadow(); /* 32b kernel does this in i386_start_kernel() */
+	x86_64_start_reservations((char *)__pa_symbol(&boot_params));
+#endif
+}
+
+static int xen_cpu_up_prepare_pv(unsigned int cpu)
+{
+	int rc;
+
+	if (per_cpu(xen_vcpu, cpu) == NULL)
+		return -ENODEV;
+
+	xen_setup_timer(cpu);
+
+	rc = xen_smp_intr_init(cpu);
+	if (rc) {
+		WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n",
+		     cpu, rc);
+		return rc;
+	}
+
+	rc = xen_smp_intr_init_pv(cpu);
+	if (rc) {
+		WARN(1, "xen_smp_intr_init_pv() for CPU %d failed: %d\n",
+		     cpu, rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int xen_cpu_dead_pv(unsigned int cpu)
+{
+	xen_smp_intr_free(cpu);
+	xen_smp_intr_free_pv(cpu);
+
+	xen_teardown_timer(cpu);
+
+	return 0;
+}
+
+static uint32_t __init xen_platform_pv(void)
+{
+	if (xen_pv_domain())
+		return xen_cpuid_base();
+
+	return 0;
+}
+
+const __initconst struct hypervisor_x86 x86_hyper_xen_pv = {
+	.name                   = "Xen PV",
+	.detect                 = xen_platform_pv,
+	.type			= X86_HYPER_XEN_PV,
+	.runtime.pin_vcpu       = xen_pin_vcpu,
+};