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    Subject[patch 14/28]xen: Xen SMP guest support
    This is a fairly straightforward Xen implementation of smp_ops.

    Xen has its own IPI mechanisms, and has no dependency on any
    APIC-based IPI. The smp_ops hooks and the flush_tlb_others pv_op
    allow a Xen guest to avoid all APIC code in arch/i386 (the only apic
    operation is a single apic_read for the apic version number).

    One subtle point which needs to be addressed is unpinning pagetables
    when another cpu may have a lazy tlb reference to the pagetable. Xen
    will not allow an in-use pagetable to be unpinned, so we must find any
    other cpus with a reference to the pagetable and get them to shoot
    down their references.

    Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
    Signed-off-by: Chris Wright <chrisw@sous-sol.org>
    Cc: Benjamin LaHaise <bcrl@kvack.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Andi Kleen <ak@suse.de>

    ---
    arch/i386/kernel/smp.c | 5
    arch/i386/kernel/smpboot.c | 8
    arch/i386/xen/Kconfig | 2
    arch/i386/xen/Makefile | 2
    arch/i386/xen/enlighten.c | 117 ++++-
    arch/i386/xen/events.c | 78 +++
    arch/i386/xen/mmu.c | 75 ++-
    arch/i386/xen/mmu.h | 13
    arch/i386/xen/setup.c | 5
    arch/i386/xen/smp.c | 405 ++++++++++++++++++++
    arch/i386/xen/time.c | 9
    arch/i386/xen/xen-ops.h | 25 +
    include/asm-i386/mach-default/irq_vectors_limits.h | 2
    include/asm-i386/mmu_context.h | 2
    include/asm-i386/smp.h | 5
    include/xen/events.h | 27 +
    16 files changed, 715 insertions(+), 65 deletions(-)

    ===================================================================
    --- a/arch/i386/kernel/smp.c
    +++ b/arch/i386/kernel/smp.c
    @@ -22,6 +22,7 @@

    #include <asm/mtrr.h>
    #include <asm/tlbflush.h>
    +#include <asm/mmu_context.h>
    #include <mach_apic.h>

    /*
    @@ -249,13 +250,13 @@ static DEFINE_SPINLOCK(tlbstate_lock);
    static DEFINE_SPINLOCK(tlbstate_lock);

    /*
    - * We cannot call mmdrop() because we are in interrupt context,
    + * We cannot call mmdrop() because we are in interrupt context,
    * instead update mm->cpu_vm_mask.
    *
    * We need to reload %cr3 since the page tables may be going
    * away from under us..
    */
    -static inline void leave_mm (unsigned long cpu)
    +void leave_mm (unsigned long cpu)
    {
    if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_OK)
    BUG();
    ===================================================================
    --- a/arch/i386/kernel/smpboot.c
    +++ b/arch/i386/kernel/smpboot.c
    @@ -148,7 +148,7 @@ void __init smp_alloc_memory(void)
    * a given CPU
    */

    -static void __cpuinit smp_store_cpu_info(int id)
    +void __cpuinit smp_store_cpu_info(int id)
    {
    struct cpuinfo_x86 *c = cpu_data + id;

    @@ -308,8 +308,7 @@ cpumask_t cpu_coregroup_map(int cpu)
    /* representing cpus for which sibling maps can be computed */
    static cpumask_t cpu_sibling_setup_map;

    -static inline void
    -set_cpu_sibling_map(int cpu)
    +void set_cpu_sibling_map(int cpu)
    {
    int i;
    struct cpuinfo_x86 *c = cpu_data;
    @@ -1157,8 +1156,7 @@ void __init native_smp_prepare_boot_cpu(
    }

    #ifdef CONFIG_HOTPLUG_CPU
    -static void
    -remove_siblinginfo(int cpu)
    +void remove_siblinginfo(int cpu)
    {
    int sibling;
    struct cpuinfo_x86 *c = cpu_data;
    ===================================================================
    --- a/arch/i386/xen/Kconfig
    +++ b/arch/i386/xen/Kconfig
    @@ -4,7 +4,7 @@

    config XEN
    bool "Enable support for Xen hypervisor"
    - depends on PARAVIRT && !PREEMPT && !SMP
    + depends on PARAVIRT && !PREEMPT
    help
    This is the Linux Xen port. Enabling this will allow the
    kernel to boot in a paravirtualized environment under the
    ===================================================================
    --- a/arch/i386/xen/Makefile
    +++ b/arch/i386/xen/Makefile
    @@ -1,2 +1,4 @@ obj-y := enlighten.o setup.o features.o
    obj-y := enlighten.o setup.o features.o multicalls.o mmu.o \
    events.o time.o
    +
    +obj-$(CONFIG_SMP) += smp.o
    ===================================================================
    --- a/arch/i386/xen/enlighten.c
    +++ b/arch/i386/xen/enlighten.c
    @@ -40,6 +40,8 @@
    #include <asm/setup.h>
    #include <asm/desc.h>
    #include <asm/pgtable.h>
    +#include <asm/smp.h>
    +#include <asm/tlbflush.h>

    #include "xen-ops.h"
    #include "mmu.h"
    @@ -56,7 +58,7 @@ struct start_info *xen_start_info;
    struct start_info *xen_start_info;
    EXPORT_SYMBOL_GPL(xen_start_info);

    -static void xen_vcpu_setup(int cpu)
    +void xen_vcpu_setup(int cpu)
    {
    per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
    }
    @@ -344,6 +346,32 @@ static void xen_write_idt_entry(struct d
    }
    }

    +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);
    +
    + put_cpu_var(idt_desc);
    +}
    +
    /* 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). */
    @@ -351,23 +379,13 @@ static void xen_load_idt(const struct Xg
    {
    static DEFINE_SPINLOCK(lock);
    static struct trap_info traps[257];
    -
    int cpu = smp_processor_id();
    - unsigned in, out, count;

    per_cpu(idt_desc, cpu) = *desc;

    - count = (desc->size+1) / 8;
    - BUG_ON(count > 256);
    -
    spin_lock(&lock);
    - 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;
    +
    + xen_convert_trap_info(desc, traps);

    xen_mc_flush();
    if (HYPERVISOR_set_trap_table(traps))
    @@ -424,6 +442,12 @@ static unsigned long xen_apic_read(unsig
    {
    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)
    @@ -445,6 +469,40 @@ static void xen_flush_tlb_single(unsigne
    BUG();
    }

    +static void xen_flush_tlb_others(const cpumask_t *cpus, struct mm_struct *mm,
    + unsigned long va)
    +{
    + struct mmuext_op op;
    + cpumask_t cpumask = *cpus;
    +
    + /*
    + * 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;
    +
    + if (va == TLB_FLUSH_ALL) {
    + op.cmd = MMUEXT_TLB_FLUSH_MULTI;
    + op.arg2.vcpumask = (void *)cpus;
    + } else {
    + op.cmd = MMUEXT_INVLPG_MULTI;
    + op.arg1.linear_addr = va;
    + op.arg2.vcpumask = (void *)cpus;
    + }
    +
    + if (HYPERVISOR_mmuext_op(&op, 1, NULL, DOMID_SELF))
    + BUG();
    +}
    +
    static unsigned long xen_read_cr2(void)
    {
    return x86_read_percpu(xen_vcpu)->arch.cr2;
    @@ -455,18 +513,6 @@ static void xen_write_cr4(unsigned long
    /* never allow TSC to be disabled */
    native_write_cr4(cr4 & ~X86_CR4_TSD);
    }
    -
    -/*
    - * Page-directory addresses above 4GB do not fit into architectural %cr3.
    - * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
    - * must use the following accessor macros to pack/unpack valid MFNs.
    - *
    - * Note that Xen is using the fact that the pagetable base is always
    - * page-aligned, and putting the 12 MSB of the address into the 12 LSB
    - * of cr3.
    - */
    -#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
    -#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))

    static unsigned long xen_read_cr3(void)
    {
    @@ -736,8 +782,8 @@ static const struct paravirt_ops xen_par
    .io_delay = xen_io_delay,

    #ifdef CONFIG_X86_LOCAL_APIC
    - .apic_write = paravirt_nop,
    - .apic_write_atomic = paravirt_nop,
    + .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,
    @@ -747,6 +793,7 @@ static const struct paravirt_ops xen_par
    .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,
    @@ -792,6 +839,19 @@ static const struct paravirt_ops xen_par
    .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 */
    +
    /* First C function to be called on Xen boot */
    asmlinkage void __init xen_start_kernel(void)
    {
    @@ -804,6 +864,9 @@ asmlinkage void __init xen_start_kernel(

    /* Install Xen paravirt ops */
    paravirt_ops = xen_paravirt_ops;
    +#ifdef CONFIG_SMP
    + smp_ops = xen_smp_ops;
    +#endif

    xen_setup_features();

    ===================================================================
    --- a/arch/i386/xen/events.c
    +++ b/arch/i386/xen/events.c
    @@ -47,6 +47,9 @@ static DEFINE_SPINLOCK(irq_mapping_updat
    /* IRQ <-> VIRQ mapping. */
    static DEFINE_PER_CPU(int, virq_to_irq[NR_VIRQS]) = {[0 ... NR_VIRQS-1] = -1};

    +/* IRQ <-> IPI mapping */
    +static DEFINE_PER_CPU(int, ipi_to_irq[XEN_NR_IPIS]) = {[0 ... XEN_NR_IPIS-1] = -1};
    +
    /* Packed IRQ information: binding type, sub-type index, and event channel. */
    struct packed_irq
    {
    @@ -58,7 +61,13 @@ static struct packed_irq irq_info[NR_IRQ
    static struct packed_irq irq_info[NR_IRQS];

    /* Binding types. */
    -enum { IRQT_UNBOUND, IRQT_PIRQ, IRQT_VIRQ, IRQT_IPI, IRQT_EVTCHN };
    +enum {
    + IRQT_UNBOUND,
    + IRQT_PIRQ,
    + IRQT_VIRQ,
    + IRQT_IPI,
    + IRQT_EVTCHN
    +};

    /* Convenient shorthand for packed representation of an unbound IRQ. */
    #define IRQ_UNBOUND mk_irq_info(IRQT_UNBOUND, 0, 0)
    @@ -261,6 +270,43 @@ static int bind_evtchn_to_irq(unsigned i
    return irq;
    }

    +static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
    +{
    + struct evtchn_bind_ipi bind_ipi;
    + int evtchn, irq;
    +
    + spin_lock(&irq_mapping_update_lock);
    +
    + if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1) {
    + if ((irq = find_unbound_irq()) < 0)
    + goto out;
    +
    + dynamic_irq_init(irq);
    + set_irq_chip_and_handler_name(irq, &xen_dynamic_chip,
    + handle_level_irq, "ipi");
    +
    + bind_ipi.vcpu = cpu;
    + if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
    + &bind_ipi) != 0)
    + BUG();
    + evtchn = bind_ipi.port;
    +
    + evtchn_to_irq[evtchn] = irq;
    + irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
    +
    + per_cpu(ipi_to_irq, cpu)[ipi] = irq;
    +
    + bind_evtchn_to_cpu(evtchn, cpu);
    + }
    +
    + irq_bindcount[irq]++;
    +
    + out:
    + spin_unlock(&irq_mapping_update_lock);
    + return irq;
    +}
    +
    +
    static int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
    {
    struct evtchn_bind_virq bind_virq;
    @@ -369,12 +415,42 @@ int bind_virq_to_irqhandler(unsigned int
    }
    EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);

    +int bind_ipi_to_irqhandler(enum ipi_vector ipi,
    + unsigned int cpu,
    + irq_handler_t handler,
    + unsigned long irqflags,
    + const char *devname,
    + void *dev_id)
    +{
    + int irq, retval;
    +
    + irq = bind_ipi_to_irq(ipi, cpu);
    + if (irq < 0)
    + return irq;
    +
    + retval = request_irq(irq, handler, irqflags, devname, dev_id);
    + if (retval != 0) {
    + unbind_from_irq(irq);
    + return retval;
    + }
    +
    + return irq;
    +}
    +
    void unbind_from_irqhandler(unsigned int irq, void *dev_id)
    {
    free_irq(irq, dev_id);
    unbind_from_irq(irq);
    }
    EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
    +
    +void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
    +{
    + int irq = per_cpu(ipi_to_irq, cpu)[vector];
    + BUG_ON(irq < 0);
    + notify_remote_via_irq(irq);
    +}
    +

    /*
    * Search the CPUs pending events bitmasks. For each one found, map
    ===================================================================
    --- a/arch/i386/xen/mmu.c
    +++ b/arch/i386/xen/mmu.c
    @@ -388,8 +388,12 @@ void xen_pgd_pin(pgd_t *pgd)

    xen_mc_batch();

    - if (pgd_walk(pgd, pin_page, TASK_SIZE))
    + if (pgd_walk(pgd, pin_page, TASK_SIZE)) {
    + /* re-enable interrupts for kmap_flush_unused */
    + xen_mc_issue(0);
    kmap_flush_unused();
    + xen_mc_batch();
    + }

    mcs = __xen_mc_entry(sizeof(*op));
    op = mcs.args;
    @@ -472,27 +476,58 @@ void xen_dup_mmap(struct mm_struct *oldm
    spin_unlock(&mm->page_table_lock);
    }

    +
    +#ifdef CONFIG_SMP
    +/* Another cpu may still have their %cr3 pointing at the pagetable, so
    + we need to repoint it somewhere else before we can unpin it. */
    +static void drop_other_mm_ref(void *info)
    +{
    + struct mm_struct *mm = info;
    +
    + if (__get_cpu_var(cpu_tlbstate).active_mm == mm)
    + leave_mm(smp_processor_id());
    +}
    +
    +static void drop_mm_ref(struct mm_struct *mm)
    +{
    + if (current->active_mm == mm) {
    + if (current->mm == mm)
    + load_cr3(swapper_pg_dir);
    + else
    + leave_mm(smp_processor_id());
    + }
    +
    + if (!cpus_empty(mm->cpu_vm_mask))
    + xen_smp_call_function_mask(mm->cpu_vm_mask, drop_other_mm_ref,
    + mm, 1);
    +}
    +#else
    +static void drop_mm_ref(struct mm_struct *mm)
    +{
    + if (current->active_mm == mm)
    + load_cr3(swapper_pg_dir);
    +}
    +#endif
    +
    +/*
    + * While a process runs, Xen pins its pagetables, which means that the
    + * hypervisor forces it to be read-only, and it controls all updates
    + * to it. This means that all pagetable updates have to go via the
    + * hypervisor, which is moderately expensive.
    + *
    + * Since we're pulling the pagetable down, we switch to use init_mm,
    + * unpin old process pagetable and mark it all read-write, which
    + * allows further operations on it to be simple memory accesses.
    + *
    + * The only subtle point is that another CPU may be still using the
    + * pagetable because of lazy tlb flushing. This means we need need to
    + * switch all CPUs off this pagetable before we can unpin it.
    + */
    void xen_exit_mmap(struct mm_struct *mm)
    {
    - struct task_struct *tsk = current;
    -
    - task_lock(tsk);
    -
    - /*
    - * We aggressively remove defunct pgd from cr3. We execute unmap_vmas()
    - * *much* faster this way, as no tlb flushes means bigger wrpt batches.
    - */
    - if (tsk->active_mm == mm) {
    - tsk->active_mm = &init_mm;
    - atomic_inc(&init_mm.mm_count);
    -
    - switch_mm(mm, &init_mm, tsk);
    -
    - atomic_dec(&mm->mm_count);
    - BUG_ON(atomic_read(&mm->mm_count) == 0);
    - }
    -
    - task_unlock(tsk);
    + get_cpu(); /* make sure we don't move around */
    + drop_mm_ref(mm);
    + put_cpu();

    xen_pgd_unpin(mm->pgd);
    }
    ===================================================================
    --- a/arch/i386/xen/mmu.h
    +++ b/arch/i386/xen/mmu.h
    @@ -2,6 +2,19 @@

    #include <linux/linkage.h>
    #include <asm/page.h>
    +
    +/*
    + * Page-directory addresses above 4GB do not fit into architectural %cr3.
    + * When accessing %cr3, or equivalent field in vcpu_guest_context, guests
    + * must use the following accessor macros to pack/unpack valid MFNs.
    + *
    + * Note that Xen is using the fact that the pagetable base is always
    + * page-aligned, and putting the 12 MSB of the address into the 12 LSB
    + * of cr3.
    + */
    +#define xen_pfn_to_cr3(pfn) (((unsigned)(pfn) << 12) | ((unsigned)(pfn) >> 20))
    +#define xen_cr3_to_pfn(cr3) (((unsigned)(cr3) >> 12) | ((unsigned)(cr3) << 20))
    +

    void set_pte_mfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags);

    ===================================================================
    --- a/arch/i386/xen/setup.c
    +++ b/arch/i386/xen/setup.c
    @@ -93,4 +93,9 @@ void __init xen_arch_setup(void)
    COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);

    pm_idle = xen_idle;
    +
    +#ifdef CONFIG_SMP
    + /* fill cpus_possible with all available cpus */
    + xen_fill_possible_map();
    +#endif
    }
    ===================================================================
    --- /dev/null
    +++ b/arch/i386/xen/smp.c
    @@ -0,0 +1,405 @@
    +/*
    + * Xen SMP support
    + *
    + * This file implements the Xen versions of smp_ops. SMP under Xen is
    + * very straightforward. Bringing a CPU up is simply a matter of
    + * loading its initial context and setting it running.
    + *
    + * IPIs are handled through the Xen event mechanism.
    + *
    + * Because virtual CPUs can be scheduled onto any real CPU, there's no
    + * useful topology information for the kernel to make use of. As a
    + * result, all CPUs are treated as if they're single-core and
    + * single-threaded.
    + *
    + * This does not handle HOTPLUG_CPU yet.
    + */
    +#include <linux/sched.h>
    +#include <linux/err.h>
    +
    +#include <asm/paravirt.h>
    +#include <asm/smp.h>
    +#include <asm/desc.h>
    +#include <asm/pgtable.h>
    +#include <asm/cpu.h>
    +
    +#include <xen/interface/xen.h>
    +#include <xen/interface/vcpu.h>
    +
    +#include <asm/xen/interface.h>
    +#include <asm/xen/hypercall.h>
    +
    +#include <xen/page.h>
    +#include <xen/events.h>
    +
    +#include "xen-ops.h"
    +#include "mmu.h"
    +
    +static cpumask_t cpu_initialized_map;
    +static DEFINE_PER_CPU(int, resched_irq);
    +static DEFINE_PER_CPU(int, callfunc_irq);
    +
    +/*
    + * Structure and data for smp_call_function(). This is designed to minimise
    + * static memory requirements. It also looks cleaner.
    + */
    +static DEFINE_SPINLOCK(call_lock);
    +
    +struct call_data_struct {
    + void (*func) (void *info);
    + void *info;
    + atomic_t started;
    + atomic_t finished;
    + int wait;
    +};
    +
    +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id);
    +
    +static struct call_data_struct *call_data;
    +
    +/*
    + * Reschedule call back. Nothing to do,
    + * all the work is done automatically when
    + * we return from the interrupt.
    + */
    +static irqreturn_t xen_reschedule_interrupt(int irq, void *dev_id)
    +{
    + return IRQ_HANDLED;
    +}
    +
    +static __cpuinit void cpu_bringup_and_idle(void)
    +{
    + int cpu = smp_processor_id();
    +
    + cpu_init();
    + xen_setup_timer();
    +
    + preempt_disable();
    + per_cpu(cpu_state, cpu) = CPU_ONLINE;
    +
    + /* We can take interrupts now: we're officially "up". */
    + local_irq_enable();
    +
    + wmb();
    + cpu_idle();
    +}
    +
    +static int xen_smp_intr_init(unsigned int cpu)
    +{
    + int rc;
    + const char *resched_name, *callfunc_name;
    +
    + per_cpu(resched_irq, cpu) = per_cpu(callfunc_irq, cpu) = -1;
    +
    + resched_name = kasprintf(GFP_KERNEL, "resched%d", cpu);
    + rc = bind_ipi_to_irqhandler(XEN_RESCHEDULE_VECTOR,
    + cpu,
    + xen_reschedule_interrupt,
    + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
    + resched_name,
    + NULL);
    + if (rc < 0)
    + goto fail;
    + per_cpu(resched_irq, cpu) = rc;
    +
    + callfunc_name = kasprintf(GFP_KERNEL, "callfunc%d", cpu);
    + rc = bind_ipi_to_irqhandler(XEN_CALL_FUNCTION_VECTOR,
    + cpu,
    + xen_call_function_interrupt,
    + IRQF_DISABLED|IRQF_PERCPU|IRQF_NOBALANCING,
    + callfunc_name,
    + NULL);
    + if (rc < 0)
    + goto fail;
    + per_cpu(callfunc_irq, cpu) = rc;
    +
    + return 0;
    +
    + fail:
    + if (per_cpu(resched_irq, cpu) >= 0)
    + unbind_from_irqhandler(per_cpu(resched_irq, cpu), NULL);
    + if (per_cpu(callfunc_irq, cpu) >= 0)
    + unbind_from_irqhandler(per_cpu(callfunc_irq, cpu), NULL);
    + return rc;
    +}
    +
    +void __init xen_fill_possible_map(void)
    +{
    + int i, rc;
    +
    + for (i = 0; i < NR_CPUS; i++) {
    + rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
    + if (rc >= 0)
    + cpu_set(i, cpu_possible_map);
    + }
    +}
    +
    +void __init xen_smp_prepare_boot_cpu(void)
    +{
    + int cpu;
    +
    + BUG_ON(smp_processor_id() != 0);
    + native_smp_prepare_boot_cpu();
    +
    + xen_vcpu_setup(0);
    +
    + /* We've switched to the "real" per-cpu gdt, so make sure the
    + old memory can be recycled */
    + make_lowmem_page_readwrite(&per_cpu__gdt_page);
    +
    + for (cpu = 0; cpu < NR_CPUS; cpu++) {
    + cpus_clear(cpu_sibling_map[cpu]);
    + cpus_clear(cpu_core_map[cpu]);
    + }
    +}
    +
    +void __init xen_smp_prepare_cpus(unsigned int max_cpus)
    +{
    + unsigned cpu;
    +
    + for (cpu = 0; cpu < NR_CPUS; cpu++) {
    + cpus_clear(cpu_sibling_map[cpu]);
    + cpus_clear(cpu_core_map[cpu]);
    + }
    +
    + smp_store_cpu_info(0);
    + set_cpu_sibling_map(0);
    +
    + if (xen_smp_intr_init(0))
    + BUG();
    +
    + cpu_initialized_map = cpumask_of_cpu(0);
    +
    + /* Restrict the possible_map according to max_cpus. */
    + while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
    + for (cpu = NR_CPUS-1; !cpu_isset(cpu, cpu_possible_map); cpu--)
    + continue;
    + cpu_clear(cpu, cpu_possible_map);
    + }
    +
    + for_each_possible_cpu (cpu) {
    + struct task_struct *idle;
    +
    + if (cpu == 0)
    + continue;
    +
    + idle = fork_idle(cpu);
    + if (IS_ERR(idle))
    + panic("failed fork for CPU %d", cpu);
    +
    + cpu_set(cpu, cpu_present_map);
    + }
    +
    + //init_xenbus_allowed_cpumask();
    +}
    +
    +static __cpuinit int
    +cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
    +{
    + struct vcpu_guest_context *ctxt;
    + struct gdt_page *gdt = &per_cpu(gdt_page, cpu);
    +
    + if (cpu_test_and_set(cpu, cpu_initialized_map))
    + return 0;
    +
    + ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
    + if (ctxt == NULL)
    + return -ENOMEM;
    +
    + ctxt->flags = VGCF_IN_KERNEL;
    + ctxt->user_regs.ds = __USER_DS;
    + ctxt->user_regs.es = __USER_DS;
    + ctxt->user_regs.fs = __KERNEL_PERCPU;
    + ctxt->user_regs.gs = 0;
    + ctxt->user_regs.ss = __KERNEL_DS;
    + ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle;
    + ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
    +
    + memset(&ctxt->fpu_ctxt, 0, sizeof(ctxt->fpu_ctxt));
    +
    + xen_copy_trap_info(ctxt->trap_ctxt);
    +
    + ctxt->ldt_ents = 0;
    +
    + BUG_ON((unsigned long)gdt->gdt & ~PAGE_MASK);
    + make_lowmem_page_readonly(gdt->gdt);
    +
    + ctxt->gdt_frames[0] = virt_to_mfn(gdt->gdt);
    + ctxt->gdt_ents = ARRAY_SIZE(gdt->gdt);
    +
    + ctxt->user_regs.cs = __KERNEL_CS;
    + ctxt->user_regs.esp = idle->thread.esp0 - sizeof(struct pt_regs);
    +
    + ctxt->kernel_ss = __KERNEL_DS;
    + ctxt->kernel_sp = idle->thread.esp0;
    +
    + ctxt->event_callback_cs = __KERNEL_CS;
    + ctxt->event_callback_eip = (unsigned long)xen_hypervisor_callback;
    + ctxt->failsafe_callback_cs = __KERNEL_CS;
    + ctxt->failsafe_callback_eip = (unsigned long)xen_failsafe_callback;
    +
    + per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
    + ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_mfn(swapper_pg_dir));
    +
    + if (HYPERVISOR_vcpu_op(VCPUOP_initialise, cpu, ctxt))
    + BUG();
    +
    + kfree(ctxt);
    + return 0;
    +}
    +
    +int __cpuinit xen_cpu_up(unsigned int cpu)
    +{
    + struct task_struct *idle = idle_task(cpu);
    + int rc;
    +
    +#if 0
    + rc = cpu_up_check(cpu);
    + if (rc)
    + return rc;
    +#endif
    +
    + init_gdt(cpu);
    + per_cpu(current_task, cpu) = idle;
    + xen_vcpu_setup(cpu);
    + irq_ctx_init(cpu);
    +
    + /* make sure interrupts start blocked */
    + per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
    +
    + rc = cpu_initialize_context(cpu, idle);
    + if (rc)
    + return rc;
    +
    + if (num_online_cpus() == 1)
    + alternatives_smp_switch(1);
    +
    + rc = xen_smp_intr_init(cpu);
    + if (rc)
    + return rc;
    +
    + /* This must be done before setting cpu_online_map */
    + smp_store_cpu_info(cpu);
    + set_cpu_sibling_map(cpu);
    + wmb();
    +
    + cpu_set(cpu, cpu_online_map);
    +
    + rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL);
    + BUG_ON(rc);
    +
    + return 0;
    +}
    +
    +void xen_smp_cpus_done(unsigned int max_cpus)
    +{
    +}
    +
    +static void stop_self(void *v)
    +{
    + int cpu = smp_processor_id();
    +
    + /* make sure we're not pinning something down */
    + load_cr3(swapper_pg_dir);
    + /* should set up a minimal gdt */
    +
    + HYPERVISOR_vcpu_op(VCPUOP_down, cpu, NULL);
    + BUG();
    +}
    +
    +void xen_smp_send_stop(void)
    +{
    + cpumask_t mask = cpu_online_map;
    + cpu_clear(smp_processor_id(), mask);
    + xen_smp_call_function_mask(mask, stop_self, NULL, 0);
    +}
    +
    +void xen_smp_send_reschedule(int cpu)
    +{
    + xen_send_IPI_one(cpu, XEN_RESCHEDULE_VECTOR);
    +}
    +
    +
    +static void xen_send_IPI_mask(cpumask_t mask, enum ipi_vector vector)
    +{
    + unsigned cpu;
    +
    + cpus_and(mask, mask, cpu_online_map);
    +
    + for_each_cpu_mask(cpu, mask)
    + xen_send_IPI_one(cpu, vector);
    +}
    +
    +static irqreturn_t xen_call_function_interrupt(int irq, void *dev_id)
    +{
    + void (*func) (void *info) = call_data->func;
    + void *info = call_data->info;
    + int wait = call_data->wait;
    +
    + /*
    + * Notify initiating CPU that I've grabbed the data and am
    + * about to execute the function
    + */
    + mb();
    + atomic_inc(&call_data->started);
    + /*
    + * At this point the info structure may be out of scope unless wait==1
    + */
    + irq_enter();
    + (*func)(info);
    + irq_exit();
    +
    + if (wait) {
    + mb();
    + atomic_inc(&call_data->finished);
    + }
    +
    + return IRQ_HANDLED;
    +}
    +
    +int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
    + void *info, int wait)
    +{
    + struct call_data_struct data;
    + int cpus;
    +
    + /* Holding any lock stops cpus from going down. */
    + spin_lock(&call_lock);
    +
    + cpu_clear(smp_processor_id(), mask);
    +
    + cpus = cpus_weight(mask);
    + if (!cpus) {
    + spin_unlock(&call_lock);
    + return 0;
    + }
    +
    + /* Can deadlock when called with interrupts disabled */
    + WARN_ON(irqs_disabled());
    +
    + data.func = func;
    + data.info = info;
    + atomic_set(&data.started, 0);
    + data.wait = wait;
    + if (wait)
    + atomic_set(&data.finished, 0);
    +
    + call_data = &data;
    + mb();
    +
    + /* Send a message to other CPUs and wait for them to respond */
    + xen_send_IPI_mask(mask, XEN_CALL_FUNCTION_VECTOR);
    +
    + /* Make sure other vcpus get a chance to run.
    + XXX too severe? Maybe we should check the other CPU's states? */
    + HYPERVISOR_sched_op(SCHEDOP_yield, 0);
    +
    + /* Wait for response */
    + while (atomic_read(&data.started) != cpus ||
    + (wait && atomic_read(&data.finished) != cpus))
    + cpu_relax();
    +
    + spin_unlock(&call_lock);
    +
    + return 0;
    +}
    ===================================================================
    --- a/arch/i386/xen/time.c
    +++ b/arch/i386/xen/time.c
    @@ -472,8 +472,9 @@ static irqreturn_t xen_timer_interrupt(i
    return ret;
    }

    -static void xen_setup_timer(int cpu)
    -{
    +void xen_setup_timer(void)
    +{
    + int cpu = smp_processor_id();
    const char *name;
    struct clock_event_device *evt;
    int irq;
    @@ -522,5 +523,5 @@ __init void xen_time_init(void)

    tsc_disable = 0;

    - xen_setup_timer(cpu);
    -}
    + xen_setup_timer();
    +}
    ===================================================================
    --- a/arch/i386/xen/xen-ops.h
    +++ b/arch/i386/xen/xen-ops.h
    @@ -2,6 +2,13 @@
    #define XEN_OPS_H

    #include <linux/init.h>
    +#include <linux/percpu.h>
    +
    +/* These are code, but not functions. Defined in entry.S */
    +extern const char xen_hypervisor_callback[];
    +extern const char xen_failsafe_callback[];
    +
    +void xen_copy_trap_info(struct trap_info *traps);

    DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
    DECLARE_PER_CPU(unsigned long, xen_cr3);
    @@ -18,6 +25,7 @@ unsigned long xen_get_wallclock(void);
    unsigned long xen_get_wallclock(void);
    int xen_set_wallclock(unsigned long time);
    unsigned long long xen_sched_clock(void);
    +void xen_setup_timer(void);

    void xen_mark_init_mm_pinned(void);

    @@ -28,5 +36,22 @@ static inline unsigned xen_get_lazy_mode
    return x86_read_percpu(xen_lazy_mode);
    }

    +void __init xen_fill_possible_map(void);
    +
    +void xen_vcpu_setup(int cpu);
    +void xen_smp_prepare_boot_cpu(void);
    +void xen_smp_prepare_cpus(unsigned int max_cpus);
    +int xen_cpu_up(unsigned int cpu);
    +void xen_smp_cpus_done(unsigned int max_cpus);
    +
    +void xen_smp_send_stop(void);
    +void xen_smp_send_reschedule(int cpu);
    +int xen_smp_call_function (void (*func) (void *info), void *info, int nonatomic,
    + int wait);
    +int xen_smp_call_function_single(int cpu, void (*func) (void *info), void *info,
    + int nonatomic, int wait);
    +
    +int xen_smp_call_function_mask(cpumask_t mask, void (*func)(void *),
    + void *info, int wait);

    #endif /* XEN_OPS_H */
    ===================================================================
    --- a/include/asm-i386/mach-default/irq_vectors_limits.h
    +++ b/include/asm-i386/mach-default/irq_vectors_limits.h
    @@ -1,7 +1,7 @@
    #ifndef _ASM_IRQ_VECTORS_LIMITS_H
    #define _ASM_IRQ_VECTORS_LIMITS_H

    -#ifdef CONFIG_X86_IO_APIC
    +#if defined(CONFIG_X86_IO_APIC) || defined(CONFIG_PARAVIRT)
    #define NR_IRQS 224
    # if (224 >= 32 * NR_CPUS)
    # define NR_IRQ_VECTORS NR_IRQS
    ===================================================================
    --- a/include/asm-i386/mmu_context.h
    +++ b/include/asm-i386/mmu_context.h
    @@ -31,6 +31,8 @@ static inline void enter_lazy_tlb(struct
    per_cpu(cpu_tlbstate, cpu).state = TLBSTATE_LAZY;
    #endif
    }
    +
    +void leave_mm (unsigned long cpu);

    static inline void switch_mm(struct mm_struct *prev,
    struct mm_struct *next,
    ===================================================================
    --- a/include/asm-i386/smp.h
    +++ b/include/asm-i386/smp.h
    @@ -43,9 +43,12 @@ extern u8 x86_cpu_to_apicid[];

    #define cpu_physical_id(cpu) x86_cpu_to_apicid[cpu]

    +extern void set_cpu_sibling_map(int cpu);
    +
    #ifdef CONFIG_HOTPLUG_CPU
    extern void cpu_exit_clear(void);
    extern void cpu_uninit(void);
    +extern void remove_siblinginfo(int cpu);
    #endif

    struct smp_ops
    @@ -143,6 +146,8 @@ extern void __cpu_die(unsigned int cpu);
    extern void __cpu_die(unsigned int cpu);
    extern unsigned int num_processors;

    +void __cpuinit smp_store_cpu_info(int id);
    +
    #endif /* !__ASSEMBLY__ */

    #else /* CONFIG_SMP */
    ===================================================================
    --- a/include/xen/events.h
    +++ b/include/xen/events.h
    @@ -1,15 +1,32 @@
    #ifndef _XEN_EVENTS_H
    #define _XEN_EVENTS_H

    -#include <linux/irq.h>
    +#include <linux/interrupt.h>
    +
    +#include <xen/interface/event_channel.h>
    +#include <asm/xen/hypercall.h>
    +
    +enum ipi_vector {
    + XEN_RESCHEDULE_VECTOR,
    + XEN_CALL_FUNCTION_VECTOR,
    +
    + XEN_NR_IPIS,
    +};

    int bind_evtchn_to_irqhandler(unsigned int evtchn,
    - irqreturn_t (*handler)(int, void *),
    + irq_handler_t handler,
    unsigned long irqflags, const char *devname,
    void *dev_id);
    int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
    - irqreturn_t (*handler)(int, void *),
    - unsigned long irqflags, const char *devname, void *dev_id);
    + irq_handler_t handler,
    + unsigned long irqflags, const char *devname,
    + void *dev_id);
    +int bind_ipi_to_irqhandler(enum ipi_vector ipi,
    + unsigned int cpu,
    + irq_handler_t handler,
    + unsigned long irqflags,
    + const char *devname,
    + void *dev_id);

    /*
    * Common unbind function for all event sources. Takes IRQ to unbind from.
    @@ -17,6 +34,8 @@ int bind_virq_to_irqhandler(unsigned int
    * made with bind_evtchn_to_irqhandler()).
    */
    void unbind_from_irqhandler(unsigned int irq, void *dev_id);
    +
    +void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector);

    static inline void notify_remote_via_evtchn(int port)
    {
    --

    -
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