1 files changed, 1146 insertions, 0 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
new file mode 100644
index 000000000000..f01bfcd4bdee
--- /dev/null
+++ b/arch/x86/xen/enlighten.c
@@ -0,0 +1,1146 @@
+/*
+ * 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/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/bootmem.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/page-flags.h>
+#include <linux/highmem.h>
+#include <linux/smp.h>
+
+#include <xen/interface/xen.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/vcpu.h>
+#include <xen/interface/sched.h>
+#include <xen/features.h>
+#include <xen/page.h>
+
+#include <asm/paravirt.h>
+#include <asm/page.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/fixmap.h>
+#include <asm/processor.h>
+#include <asm/setup.h>
+#include <asm/desc.h>
+#include <asm/pgtable.h>
+#include <asm/tlbflush.h>
+#include <asm/reboot.h>
+
+#include "xen-ops.h"
+#include "mmu.h"
+#include "multicalls.h"
+
+EXPORT_SYMBOL_GPL(hypercall_page);
+
+DEFINE_PER_CPU(enum paravirt_lazy_mode, xen_lazy_mode);
+
+DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu);
+DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info);
+DEFINE_PER_CPU(unsigned long, xen_cr3);
+
+struct start_info *xen_start_info;
+EXPORT_SYMBOL_GPL(xen_start_info);
+
+static /* __initdata */ struct shared_info dummy_shared_info;
+
+/*
+ * Point at some empty memory to start with. We map the real shared_info
+ * page as soon as fixmap is up and running.
+ */
+struct shared_info *HYPERVISOR_shared_info = (void *)&dummy_shared_info;
+
+/*
+ * Flag to determine whether vcpu info placement is available on all
+ * VCPUs.  We assume it is to start with, and then set it to zero on
+ * the first failure.  This is because it can succeed on some VCPUs
+ * and not others, since it can involve hypervisor memory allocation,
+ * or because the guest failed to guarantee all the appropriate
+ * constraints on all VCPUs (ie buffer can't cross a page boundary).
+ *
+ * Note that any particular CPU may be using a placed vcpu structure,
+ * but we can only optimise if the all are.
+ *
+ * 0: not available, 1: available
+ */
+static int have_vcpu_info_placement = 1;
+
+static void __init xen_vcpu_setup(int cpu)
+{
+        struct vcpu_register_vcpu_info info;
+        int err;
+        struct vcpu_info *vcpup;
+
+        per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+
+        if (!have_vcpu_info_placement)
+                return;         /* already tested, not available */
+
+        vcpup = &per_cpu(xen_vcpu_info, cpu);
+
+        info.mfn = virt_to_mfn(vcpup);
+        info.offset = offset_in_page(vcpup);
+
+        printk(KERN_DEBUG "trying to map vcpu_info %d at %p, mfn %x, offset %d\n",
+               cpu, vcpup, info.mfn, info.offset);
+
+        /* Check to see if the hypervisor will put the vcpu_info
+           structure where we want it, which allows direct access via
+           a percpu-variable. */
+        err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
+
+        if (err) {
+                printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
+                have_vcpu_info_placement = 0;
+        } else {
+                /* This cpu is using the registered vcpu info, even if
+                   later ones fail to. */
+                per_cpu(xen_vcpu, cpu) = vcpup;
+
+                printk(KERN_DEBUG "cpu %d using vcpu_info at %p\n",
+                       cpu, vcpup);
+        }
+}
+
+static void __init xen_banner(void)
+{
+        printk(KERN_INFO "Booting paravirtualized kernel on %s\n",
+               paravirt_ops.name);
+        printk(KERN_INFO "Hypervisor signature: %s\n", xen_start_info->magic);
+}
+
+static void xen_cpuid(unsigned int *eax, unsigned int *ebx,
+                      unsigned int *ecx, unsigned int *edx)
+{
+        unsigned maskedx = ~0;
+
+        /*
+         * Mask out inconvenient features, to try and disable as many
+         * unsupported kernel subsystems as possible.
+         */
+        if (*eax == 1)
+                maskedx = ~((1 << X86_FEATURE_APIC) |  /* disable APIC */
+                            (1 << X86_FEATURE_ACPI) |  /* disable ACPI */
+                            (1 << X86_FEATURE_ACC));   /* thermal monitoring */
+
+        asm(XEN_EMULATE_PREFIX "cpuid"
+                : "=a" (*eax),
+                  "=b" (*ebx),
+                  "=c" (*ecx),
+                  "=d" (*edx)
+                : "0" (*eax), "2" (*ecx));
+        *edx &= maskedx;
+}
+
+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 unsigned long xen_save_fl(void)
+{
+        struct vcpu_info *vcpu;
+        unsigned long flags;
+
+        vcpu = x86_read_percpu(xen_vcpu);
+
+        /* flag has opposite sense of mask */
+        flags = !vcpu->evtchn_upcall_mask;
+
+        /* convert to IF type flag
+           -0 -> 0x00000000
+           -1 -> 0xffffffff
+        */
+        return (-flags) & X86_EFLAGS_IF;
+}
+
+static void xen_restore_fl(unsigned long flags)
+{
+        struct vcpu_info *vcpu;
+
+        /* convert from IF type flag */
+        flags = !(flags & X86_EFLAGS_IF);
+
+        /* There's a one instruction preempt window here.  We need to
+           make sure we're don't switch CPUs between getting the vcpu
+           pointer and updating the mask. */
+        preempt_disable();
+        vcpu = x86_read_percpu(xen_vcpu);
+        vcpu->evtchn_upcall_mask = flags;
+        preempt_enable_no_resched();
+
+        /* Doesn't matter if we get preempted here, because any
+           pending event will get dealt with anyway. */
+
+        if (flags == 0) {
+                preempt_check_resched();
+                barrier(); /* unmask then check (avoid races) */
+                if (unlikely(vcpu->evtchn_upcall_pending))
+                        force_evtchn_callback();
+        }
+}
+
+static void xen_irq_disable(void)
+{
+        /* There's a one instruction preempt window here.  We need to
+           make sure we're don't switch CPUs between getting the vcpu
+           pointer and updating the mask. */
+        preempt_disable();
+        x86_read_percpu(xen_vcpu)->evtchn_upcall_mask = 1;
+        preempt_enable_no_resched();
+}
+
+static void xen_irq_enable(void)
+{
+        struct vcpu_info *vcpu;
+
+        /* There's a one instruction preempt window here.  We need to
+           make sure we're don't switch CPUs between getting the vcpu
+           pointer and updating the mask. */
+        preempt_disable();
+        vcpu = x86_read_percpu(xen_vcpu);
+        vcpu->evtchn_upcall_mask = 0;
+        preempt_enable_no_resched();
+
+        /* Doesn't matter if we get preempted here, because any
+           pending event will get dealt with anyway. */
+
+        barrier(); /* unmask then check (avoid races) */
+        if (unlikely(vcpu->evtchn_upcall_pending))
+                force_evtchn_callback();
+}
+
+static void xen_safe_halt(void)
+{
+        /* Blocking includes an implicit local_irq_enable(). */
+        if (HYPERVISOR_sched_op(SCHEDOP_block, 0) != 0)
+                BUG();
+}
+
+static void xen_halt(void)
+{
+        if (irqs_disabled())
+                HYPERVISOR_vcpu_op(VCPUOP_down, smp_processor_id(), NULL);
+        else
+                xen_safe_halt();
+}
+
+static void xen_set_lazy_mode(enum paravirt_lazy_mode mode)
+{
+        BUG_ON(preemptible());
+
+        switch (mode) {
+        case PARAVIRT_LAZY_NONE:
+                BUG_ON(x86_read_percpu(xen_lazy_mode) == PARAVIRT_LAZY_NONE);
+                break;
+
+        case PARAVIRT_LAZY_MMU:
+        case PARAVIRT_LAZY_CPU:
+                BUG_ON(x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE);
+                break;
+
+        case PARAVIRT_LAZY_FLUSH:
+                /* flush if necessary, but don't change state */
+                if (x86_read_percpu(xen_lazy_mode) != PARAVIRT_LAZY_NONE)
+                        xen_mc_flush();
+                return;
+        }
+
+        xen_mc_flush();
+        x86_write_percpu(xen_lazy_mode, mode);
+}
+
+static unsigned long xen_store_tr(void)
+{
+        return 0;
+}
+
+static void xen_set_ldt(const void *addr, unsigned entries)
+{
+        unsigned long linear_addr = (unsigned long)addr;
+        struct mmuext_op *op;
+        struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+        op = mcs.args;
+        op->cmd = MMUEXT_SET_LDT;
+        if (linear_addr) {
+                /* ldt my be vmalloced, use arbitrary_virt_to_machine */
+                xmaddr_t maddr;
+                maddr = arbitrary_virt_to_machine((unsigned long)addr);
+                linear_addr = (unsigned long)maddr.maddr;
+        }
+        op->arg1.linear_addr = linear_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 Xgt_desc_struct *dtr)
+{
+        unsigned long *frames;
+        unsigned long va = dtr->address;
+        unsigned int size = dtr->size + 1;
+        unsigned pages = (size + PAGE_SIZE - 1) / PAGE_SIZE;
+        int f;
+        struct multicall_space mcs;
+
+        /* A GDT can be up to 64k in size, which corresponds to 8192
+           8-byte entries, or 16 4k pages.. */
+
+        BUG_ON(size > 65536);
+        BUG_ON(va & ~PAGE_MASK);
+
+        mcs = xen_mc_entry(sizeof(*frames) * pages);
+        frames = mcs.args;
+
+        for (f = 0; va < dtr->address + size; va += PAGE_SIZE, f++) {
+                frames[f] = virt_to_mfn(va);
+                make_lowmem_page_readonly((void *)va);
+        }
+
+        MULTI_set_gdt(mcs.mc, frames, size / sizeof(struct desc_struct));
+
+        xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static void load_TLS_descriptor(struct thread_struct *t,
+                                unsigned int cpu, unsigned int i)
+{
+        struct desc_struct *gdt = get_cpu_gdt_table(cpu);
+        xmaddr_t maddr = virt_to_machine(&gdt[GDT_ENTRY_TLS_MIN+i]);
+        struct multicall_space 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)
+{
+        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);
+
+        /*
+         * XXX sleazy hack: If we're being called in a lazy-cpu zone,
+         * 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.
+         */
+        if (xen_get_lazy_mode() == PARAVIRT_LAZY_CPU)
+                loadsegment(gs, 0);
+}
+
+static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
+                                u32 low, u32 high)
+{
+        unsigned long lp = (unsigned long)&dt[entrynum];
+        xmaddr_t mach_lp = virt_to_machine(lp);
+        u64 entry = (u64)high << 32 | low;
+
+        preempt_disable();
+
+        xen_mc_flush();
+        if (HYPERVISOR_update_descriptor(mach_lp.maddr, entry))
+                BUG();
+
+        preempt_enable();
+}
+
+static int cvt_gate_to_trap(int vector, u32 low, u32 high,
+                            struct trap_info *info)
+{
+        u8 type, dpl;
+
+        type = (high >> 8) & 0x1f;
+        dpl = (high >> 13) & 3;
+
+        if (type != 0xf && type != 0xe)
+                return 0;
+
+        info->vector = vector;
+        info->address = (high & 0xffff0000) | (low & 0x0000ffff);
+        info->cs = low >> 16;
+        info->flags = dpl;
+        /* interrupt gates clear IF */
+        if (type == 0xe)
+                info->flags |= 4;
+
+        return 1;
+}
+
+/* Locations of each CPU's IDT */
+static DEFINE_PER_CPU(struct Xgt_desc_struct, 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(struct desc_struct *dt, int entrynum,
+                                u32 low, u32 high)
+{
+        unsigned long p = (unsigned long)&dt[entrynum];
+        unsigned long start, end;
+
+        preempt_disable();
+
+        start = __get_cpu_var(idt_desc).address;
+        end = start + __get_cpu_var(idt_desc).size + 1;
+
+        xen_mc_flush();
+
+        write_dt_entry(dt, entrynum, low, high);
+
+        if (p >= start && (p + 8) <= end) {
+                struct trap_info info[2];
+
+                info[1].address = 0;
+
+                if (cvt_gate_to_trap(entrynum, low, high, &info[0]))
+                        if (HYPERVISOR_set_trap_table(info))
+                                BUG();
+        }
+
+        preempt_enable();
+}
+
+static void xen_convert_trap_info(const struct Xgt_desc_struct *desc,
+                                  struct trap_info *traps)
+{
+        unsigned in, out, count;
+
+        count = (desc->size+1) / 8;
+        BUG_ON(count > 256);
+
+        for (in = out = 0; in < count; in++) {
+                const u32 *entry = (u32 *)(desc->address + in * 8);
+
+                if (cvt_gate_to_trap(in, entry[0], entry[1], &traps[out]))
+                        out++;
+        }
+        traps[out].address = 0;
+}
+
+void xen_copy_trap_info(struct trap_info *traps)
+{
+        const struct Xgt_desc_struct *desc = &__get_cpu_var(idt_desc);
+
+        xen_convert_trap_info(desc, traps);
+}
+
+/* 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 Xgt_desc_struct *desc)
+{
+        static DEFINE_SPINLOCK(lock);
+        static struct trap_info traps[257];
+
+        spin_lock(&lock);
+
+        __get_cpu_var(idt_desc) = *desc;
+
+        xen_convert_trap_info(desc, traps);
+
+        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,
+                                u32 low, u32 high)
+{
+        preempt_disable();
+
+        switch ((high >> 8) & 0xff) {
+        case DESCTYPE_LDT:
+        case DESCTYPE_TSS:
+                /* ignore */
+                break;
+
+        default: {
+                xmaddr_t maddr = virt_to_machine(&dt[entry]);
+                u64 desc = (u64)high << 32 | low;
+
+                xen_mc_flush();
+                if (HYPERVISOR_update_descriptor(maddr.maddr, desc))
+                        BUG();
+        }
+
+        }
+
+        preempt_enable();
+}
+
+static void xen_load_esp0(struct tss_struct *tss,
+                          struct thread_struct *thread)
+{
+        struct multicall_space mcs = xen_mc_entry(0);
+        MULTI_stack_switch(mcs.mc, __KERNEL_DS, thread->esp0);
+        xen_mc_issue(PARAVIRT_LAZY_CPU);
+}
+
+static 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)
+{
+}
+
+#ifdef CONFIG_X86_LOCAL_APIC
+static unsigned long xen_apic_read(unsigned long reg)
+{
+        return 0;
+}
+
+static void xen_apic_write(unsigned long reg, unsigned long val)
+{
+        /* Warn to see if there's any stray references */
+        WARN_ON(1);
+}
+#endif
+
+static void xen_flush_tlb(void)
+{
+        struct mmuext_op *op;
+        struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+        op = mcs.args;
+        op->cmd = MMUEXT_TLB_FLUSH_LOCAL;
+        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+        xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static void xen_flush_tlb_single(unsigned long addr)
+{
+        struct mmuext_op *op;
+        struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+
+        op = mcs.args;
+        op->cmd = MMUEXT_INVLPG_LOCAL;
+        op->arg1.linear_addr = addr & PAGE_MASK;
+        MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+        xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
+                                 unsigned long va)
+{
+        struct {
+                struct mmuext_op op;
+                cpumask_t mask;
+        } *args;
+        cpumask_t cpumask = *cpus;
+        struct multicall_space mcs;
+
+        /*
+         * A couple of (to be removed) sanity checks:
+         *
+         * - current CPU must not be in mask
+         * - mask must exist :)
+         */
+        BUG_ON(cpus_empty(cpumask));
+        BUG_ON(cpu_isset(smp_processor_id(), cpumask));
+        BUG_ON(!mm);
+
+        /* If a CPU which we ran on has gone down, OK. */
+        cpus_and(cpumask, cpumask, cpu_online_map);
+        if (cpus_empty(cpumask))
+                return;
+
+        mcs = xen_mc_entry(sizeof(*args));
+        args = mcs.args;
+        args->mask = cpumask;
+        args->op.arg2.vcpumask = &args->mask;
+
+        if (va == TLB_FLUSH_ALL) {
+                args->op.cmd = MMUEXT_TLB_FLUSH_MULTI;
+        } else {
+                args->op.cmd = MMUEXT_INVLPG_MULTI;
+                args->op.arg1.linear_addr = va;
+        }
+
+        MULTI_mmuext_op(mcs.mc, &args->op, 1, NULL, DOMID_SELF);
+
+        xen_mc_issue(PARAVIRT_LAZY_MMU);
+}
+
+static void xen_write_cr2(unsigned long cr2)
+{
+        x86_read_percpu(xen_vcpu)->arch.cr2 = cr2;
+}
+
+static unsigned long xen_read_cr2(void)
+{
+        return x86_read_percpu(xen_vcpu)->arch.cr2;
+}
+
+static unsigned long xen_read_cr2_direct(void)
+{
+        return x86_read_percpu(xen_vcpu_info.arch.cr2);
+}
+
+static void xen_write_cr4(unsigned long cr4)
+{
+        /* Just ignore cr4 changes; Xen doesn't allow us to do
+           anything anyway. */
+}
+
+static unsigned long xen_read_cr3(void)
+{
+        return x86_read_percpu(xen_cr3);
+}
+
+static void xen_write_cr3(unsigned long cr3)
+{
+        BUG_ON(preemptible());
+
+        if (cr3 == x86_read_percpu(xen_cr3)) {
+                /* just a simple tlb flush */
+                xen_flush_tlb();
+                return;
+        }
+
+        x86_write_percpu(xen_cr3, cr3);
+
+
+        {
+                struct mmuext_op *op;
+                struct multicall_space mcs = xen_mc_entry(sizeof(*op));
+                unsigned long mfn = pfn_to_mfn(PFN_DOWN(cr3));
+
+                op = mcs.args;
+                op->cmd = MMUEXT_NEW_BASEPTR;
+                op->arg1.mfn = mfn;
+
+                MULTI_mmuext_op(mcs.mc, op, 1, NULL, DOMID_SELF);
+
+                xen_mc_issue(PARAVIRT_LAZY_CPU);
+        }
+}
+
+/* Early in boot, while setting up the initial pagetable, assume
+   everything is pinned. */
+static __init void xen_alloc_pt_init(struct mm_struct *mm, u32 pfn)
+{
+        BUG_ON(mem_map);        /* should only be used early */
+        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+}
+
+/* This needs to make sure the new pte page is pinned iff its being
+   attached to a pinned pagetable. */
+static void xen_alloc_pt(struct mm_struct *mm, u32 pfn)
+{
+        struct page *page = pfn_to_page(pfn);
+
+        if (PagePinned(virt_to_page(mm->pgd))) {
+                SetPagePinned(page);
+
+                if (!PageHighMem(page))
+                        make_lowmem_page_readonly(__va(PFN_PHYS(pfn)));
+                else
+                        /* make sure there are no stray mappings of
+                           this page */
+                        kmap_flush_unused();
+        }
+}
+
+/* This should never happen until we're OK to use struct page */
+static void xen_release_pt(u32 pfn)
+{
+        struct page *page = pfn_to_page(pfn);
+
+        if (PagePinned(page)) {
+                if (!PageHighMem(page))
+                        make_lowmem_page_readwrite(__va(PFN_PHYS(pfn)));
+        }
+}
+
+#ifdef CONFIG_HIGHPTE
+static void *xen_kmap_atomic_pte(struct page *page, enum km_type type)
+{
+        pgprot_t prot = PAGE_KERNEL;
+
+        if (PagePinned(page))
+                prot = PAGE_KERNEL_RO;
+
+        if (0 && PageHighMem(page))
+                printk("mapping highpte %lx type %d prot %s\n",
+                       page_to_pfn(page), type,
+                       (unsigned long)pgprot_val(prot) & _PAGE_RW ? "WRITE" : "READ");
+
+        return kmap_atomic_prot(page, type, prot);
+}
+#endif
+
+static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+        /* If there's an existing pte, then don't allow _PAGE_RW to be set */
+        if (pte_val_ma(*ptep) & _PAGE_PRESENT)
+                pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
+                               pte_val_ma(pte));
+
+        return pte;
+}
+
+/* Init-time set_pte while constructing initial pagetables, which
+   doesn't allow RO pagetable pages to be remapped RW */
+static __init void xen_set_pte_init(pte_t *ptep, pte_t pte)
+{
+        pte = mask_rw_pte(ptep, pte);
+
+        xen_set_pte(ptep, pte);
+}
+
+static __init void xen_pagetable_setup_start(pgd_t *base)
+{
+        pgd_t *xen_pgd = (pgd_t *)xen_start_info->pt_base;
+
+        /* special set_pte for pagetable initialization */
+        paravirt_ops.set_pte = xen_set_pte_init;
+
+        init_mm.pgd = base;
+        /*
+         * copy top-level of Xen-supplied pagetable into place.  For
+         * !PAE we can use this as-is, but for PAE it is a stand-in
+         * while we copy the pmd pages.
+         */
+        memcpy(base, xen_pgd, PTRS_PER_PGD * sizeof(pgd_t));
+
+        if (PTRS_PER_PMD > 1) {
+                int i;
+                /*
+                 * For PAE, need to allocate new pmds, rather than
+                 * share Xen's, since Xen doesn't like pmd's being
+                 * shared between address spaces.
+                 */
+                for (i = 0; i < PTRS_PER_PGD; i++) {
+                        if (pgd_val_ma(xen_pgd[i]) & _PAGE_PRESENT) {
+                                pmd_t *pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
+
+                                memcpy(pmd, (void *)pgd_page_vaddr(xen_pgd[i]),
+                                       PAGE_SIZE);
+
+                                make_lowmem_page_readonly(pmd);
+
+                                set_pgd(&base[i], __pgd(1 + __pa(pmd)));
+                        } else
+                                pgd_clear(&base[i]);
+                }
+        }
+
+        /* make sure zero_page is mapped RO so we can use it in pagetables */
+        make_lowmem_page_readonly(empty_zero_page);
+        make_lowmem_page_readonly(base);
+        /*
+         * Switch to new pagetable.  This is done before
+         * pagetable_init has done anything so that the new pages
+         * added to the table can be prepared properly for Xen.
+         */
+        xen_write_cr3(__pa(base));
+}
+
+static __init void xen_pagetable_setup_done(pgd_t *base)
+{
+        /* This will work as long as patching hasn't happened yet
+           (which it hasn't) */
+        paravirt_ops.alloc_pt = xen_alloc_pt;
+        paravirt_ops.set_pte = xen_set_pte;
+
+        if (!xen_feature(XENFEAT_auto_translated_physmap)) {
+                /*
+                 * Create a mapping for the shared info page.
+                 * Should be set_fixmap(), but shared_info is a machine
+                 * address with no corresponding pseudo-phys address.
+                 */
+                set_pte_mfn(fix_to_virt(FIX_PARAVIRT_BOOTMAP),
+                            PFN_DOWN(xen_start_info->shared_info),
+                            PAGE_KERNEL);
+
+                HYPERVISOR_shared_info =
+                        (struct shared_info *)fix_to_virt(FIX_PARAVIRT_BOOTMAP);
+
+        } else
+                HYPERVISOR_shared_info =
+                        (struct shared_info *)__va(xen_start_info->shared_info);
+
+        /* Actually pin the pagetable down, but we can't set PG_pinned
+           yet because the page structures don't exist yet. */
+        {
+                struct mmuext_op op;
+#ifdef CONFIG_X86_PAE
+                op.cmd = MMUEXT_PIN_L3_TABLE;
+#else
+                op.cmd = MMUEXT_PIN_L3_TABLE;
+#endif
+                op.arg1.mfn = pfn_to_mfn(PFN_DOWN(__pa(base)));
+                if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
+                        BUG();
+        }
+}
+
+/* This is called once we have the cpu_possible_map */
+void __init xen_setup_vcpu_info_placement(void)
+{
+        int cpu;
+
+        for_each_possible_cpu(cpu)
+                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 (have_vcpu_info_placement) {
+                printk(KERN_INFO "Xen: using vcpu_info placement\n");
+
+                paravirt_ops.save_fl = xen_save_fl_direct;
+                paravirt_ops.restore_fl = xen_restore_fl_direct;
+                paravirt_ops.irq_disable = xen_irq_disable_direct;
+                paravirt_ops.irq_enable = xen_irq_enable_direct;
+                paravirt_ops.read_cr2 = xen_read_cr2_direct;
+                paravirt_ops.iret = xen_iret_direct;
+        }
+}
+
+static unsigned xen_patch(u8 type, u16 clobbers, void *insnbuf,
+                          unsigned long addr, unsigned len)
+{
+        char *start, *end, *reloc;
+        unsigned ret;
+
+        start = end = reloc = NULL;
+
+#define SITE(x)                                                         \
+        case PARAVIRT_PATCH(x):                                         \
+        if (have_vcpu_info_placement) {                                 \
+                start = (char *)xen_##x##_direct;                       \
+                end = xen_##x##_direct_end;                             \
+                reloc = xen_##x##_direct_reloc;                         \
+        }                                                               \
+        goto patch_site
+
+        switch (type) {
+                SITE(irq_enable);
+                SITE(irq_disable);
+                SITE(save_fl);
+                SITE(restore_fl);
+#undef SITE
+
+        patch_site:
+                if (start == NULL || (end-start) > len)
+                        goto default_patch;
+
+                ret = paravirt_patch_insns(insnbuf, len, start, end);
+
+                /* Note: because reloc is assigned from something that
+                   appears to be an array, gcc assumes it's non-null,
+                   but doesn't know its relationship with start and
+                   end. */
+                if (reloc > start && reloc < end) {
+                        int reloc_off = reloc - start;
+                        long *relocp = (long *)(insnbuf + reloc_off);
+                        long delta = start - (char *)addr;
+
+                        *relocp += delta;
+                }
+                break;
+
+        default_patch:
+        default:
+                ret = paravirt_patch_default(type, clobbers, insnbuf,
+                                             addr, len);
+                break;
+        }
+
+        return ret;
+}
+
+static const struct paravirt_ops xen_paravirt_ops __initdata = {
+        .paravirt_enabled = 1,
+        .shared_kernel_pmd = 0,
+
+        .name = "Xen",
+        .banner = xen_banner,
+
+        .patch = xen_patch,
+
+        .memory_setup = xen_memory_setup,
+        .arch_setup = xen_arch_setup,
+        .init_IRQ = xen_init_IRQ,
+        .post_allocator_init = xen_mark_init_mm_pinned,
+
+        .time_init = xen_time_init,
+        .set_wallclock = xen_set_wallclock,
+        .get_wallclock = xen_get_wallclock,
+        .get_cpu_khz = xen_cpu_khz,
+        .sched_clock = xen_sched_clock,
+
+        .cpuid = xen_cpuid,
+
+        .set_debugreg = xen_set_debugreg,
+        .get_debugreg = xen_get_debugreg,
+
+        .clts = native_clts,
+
+        .read_cr0 = native_read_cr0,
+        .write_cr0 = native_write_cr0,
+
+        .read_cr2 = xen_read_cr2,
+        .write_cr2 = xen_write_cr2,
+
+        .read_cr3 = xen_read_cr3,
+        .write_cr3 = xen_write_cr3,
+
+        .read_cr4 = native_read_cr4,
+        .read_cr4_safe = native_read_cr4_safe,
+        .write_cr4 = xen_write_cr4,
+
+        .save_fl = xen_save_fl,
+        .restore_fl = xen_restore_fl,
+        .irq_disable = xen_irq_disable,
+        .irq_enable = xen_irq_enable,
+        .safe_halt = xen_safe_halt,
+        .halt = xen_halt,
+        .wbinvd = native_wbinvd,
+
+        .read_msr = native_read_msr_safe,
+        .write_msr = native_write_msr_safe,
+        .read_tsc = native_read_tsc,
+        .read_pmc = native_read_pmc,
+
+        .iret = (void *)&hypercall_page[__HYPERVISOR_iret],
+        .irq_enable_sysexit = NULL,  /* never called */
+
+        .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,
+
+        .store_gdt = native_store_gdt,
+        .store_idt = native_store_idt,
+        .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_esp0 = xen_load_esp0,
+
+        .set_iopl_mask = xen_set_iopl_mask,
+        .io_delay = xen_io_delay,
+
+#ifdef CONFIG_X86_LOCAL_APIC
+        .apic_write = xen_apic_write,
+        .apic_write_atomic = xen_apic_write,
+        .apic_read = xen_apic_read,
+        .setup_boot_clock = paravirt_nop,
+        .setup_secondary_clock = paravirt_nop,
+        .startup_ipi_hook = paravirt_nop,
+#endif
+
+        .flush_tlb_user = xen_flush_tlb,
+        .flush_tlb_kernel = xen_flush_tlb,
+        .flush_tlb_single = xen_flush_tlb_single,
+        .flush_tlb_others = xen_flush_tlb_others,
+
+        .pte_update = paravirt_nop,
+        .pte_update_defer = paravirt_nop,
+
+        .pagetable_setup_start = xen_pagetable_setup_start,
+        .pagetable_setup_done = xen_pagetable_setup_done,
+
+        .alloc_pt = xen_alloc_pt_init,
+        .release_pt = xen_release_pt,
+        .alloc_pd = paravirt_nop,
+        .alloc_pd_clone = paravirt_nop,
+        .release_pd = paravirt_nop,
+
+#ifdef CONFIG_HIGHPTE
+        .kmap_atomic_pte = xen_kmap_atomic_pte,
+#endif
+
+        .set_pte = NULL,        /* see xen_pagetable_setup_* */
+        .set_pte_at = xen_set_pte_at,
+        .set_pmd = xen_set_pmd,
+
+        .pte_val = xen_pte_val,
+        .pgd_val = xen_pgd_val,
+
+        .make_pte = xen_make_pte,
+        .make_pgd = xen_make_pgd,
+
+#ifdef CONFIG_X86_PAE
+        .set_pte_atomic = xen_set_pte_atomic,
+        .set_pte_present = xen_set_pte_at,
+        .set_pud = xen_set_pud,
+        .pte_clear = xen_pte_clear,
+        .pmd_clear = xen_pmd_clear,
+
+        .make_pmd = xen_make_pmd,
+        .pmd_val = xen_pmd_val,
+#endif  /* PAE */
+
+        .activate_mm = xen_activate_mm,
+        .dup_mmap = xen_dup_mmap,
+        .exit_mmap = xen_exit_mmap,
+
+        .set_lazy_mode = xen_set_lazy_mode,
+};
+
+#ifdef CONFIG_SMP
+static const struct smp_ops xen_smp_ops __initdata = {
+        .smp_prepare_boot_cpu = xen_smp_prepare_boot_cpu,
+        .smp_prepare_cpus = xen_smp_prepare_cpus,
+        .cpu_up = xen_cpu_up,
+        .smp_cpus_done = xen_smp_cpus_done,
+
+        .smp_send_stop = xen_smp_send_stop,
+        .smp_send_reschedule = xen_smp_send_reschedule,
+        .smp_call_function_mask = xen_smp_call_function_mask,
+};
+#endif  /* CONFIG_SMP */
+
+static void xen_reboot(int reason)
+{
+#ifdef CONFIG_SMP
+        smp_send_stop();
+#endif
+
+        if (HYPERVISOR_sched_op(SCHEDOP_shutdown, reason))
+                BUG();
+}
+
+static void xen_restart(char *msg)
+{
+        xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_emergency_restart(void)
+{
+        xen_reboot(SHUTDOWN_reboot);
+}
+
+static void xen_machine_halt(void)
+{
+        xen_reboot(SHUTDOWN_poweroff);
+}
+
+static void xen_crash_shutdown(struct pt_regs *regs)
+{
+        xen_reboot(SHUTDOWN_crash);
+}
+
+static const struct machine_ops __initdata xen_machine_ops = {
+        .restart = xen_restart,
+        .halt = xen_machine_halt,
+        .power_off = xen_machine_halt,
+        .shutdown = xen_machine_halt,
+        .crash_shutdown = xen_crash_shutdown,
+        .emergency_restart = xen_emergency_restart,
+};
+
+
+/* First C function to be called on Xen boot */
+asmlinkage void __init xen_start_kernel(void)
+{
+        pgd_t *pgd;
+
+        if (!xen_start_info)
+                return;
+
+        BUG_ON(memcmp(xen_start_info->magic, "xen-3.0", 7) != 0);
+
+        /* Install Xen paravirt ops */
+        paravirt_ops = xen_paravirt_ops;
+        machine_ops = xen_machine_ops;
+
+#ifdef CONFIG_SMP
+        smp_ops = xen_smp_ops;
+#endif
+
+        xen_setup_features();
+
+        /* Get mfn list */
+        if (!xen_feature(XENFEAT_auto_translated_physmap))
+                phys_to_machine_mapping = (unsigned long *)xen_start_info->mfn_list;
+
+        pgd = (pgd_t *)xen_start_info->pt_base;
+
+        init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
+
+        init_mm.pgd = pgd; /* use the Xen pagetables to start */
+
+        /* keep using Xen gdt for now; no urgent need to change it */
+
+        x86_write_percpu(xen_cr3, __pa(pgd));
+
+#ifdef CONFIG_SMP
+        /* Don't do the full vcpu_info placement stuff until we have a
+           possible map. */
+        per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
+#else
+        /* May as well do it now, since there's no good time to call
+           it later on UP. */
+        xen_setup_vcpu_info_placement();
+#endif
+
+        paravirt_ops.kernel_rpl = 1;
+        if (xen_feature(XENFEAT_supervisor_mode_kernel))
+                paravirt_ops.kernel_rpl = 0;
+
+        /* set the limit of our address space */
+        reserve_top_address(-HYPERVISOR_VIRT_START + 2 * PAGE_SIZE);
+
+        /* set up basic CPUID stuff */
+        cpu_detect(&new_cpu_data);
+        new_cpu_data.hard_math = 1;
+        new_cpu_data.x86_capability[0] = cpuid_edx(1);
+
+        /* Poke various useful things into boot_params */
+        LOADER_TYPE = (9 << 4) | 0;
+        INITRD_START = xen_start_info->mod_start ? __pa(xen_start_info->mod_start) : 0;
+        INITRD_SIZE = xen_start_info->mod_len;
+
+        /* Start the world */
+        start_kernel();
+}