[patch 15/29] xen: Xen SMP guest support

Jeremy Fitzhardinge
2007-05-04T23:44:46Z

[-- Attachment #1: xen-smp.patch --]
[-- Type: text/plain, Size: 30984 bytes --]

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 | 119 ++++-
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, 717 insertions(+), 65 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -23,6 +23,7 @@

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

/*
@@ -250,13 +251,13 @@ 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
@@ -149,7 +149,7 @@ 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;

@@ -309,8 +309,7 @@ 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;
@@ -1145,8 +1144,7 @@ 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
@@ -4,6 +4,6 @@

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
===================================================================
--- 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))
@@ -422,7 +440,15 @@ static void xen_io_delay(void)
#ifdef CONFIG_X86_LOCAL_APIC
static unsigned long xen_apic_read(unsigned long reg)
{
+ /* Warn to see if there's any stray references */
+ WARN_ON(1);
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

@@ -445,6 +471,40 @@ 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 +515,6 @@ 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 +784,8 @@ 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 +795,7 @@ 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 +841,19 @@ 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 */
static asmlinkage void __init xen_start_kernel(void)
{
@@ -804,6 +866,9 @@ static asmlinkage void __init xen_start_

/* 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)
{

--