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>
diff --git a/arch/i386/xen/events.c b/arch/i386/xen/events.c
index e7c5d00..4103b8b 100644
--- a/arch/i386/xen/events.c
+++ b/arch/i386/xen/events.c
@@ -47,6 +47,9 @@
/* 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_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 +270,45 @@
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);
+
+ irq = per_cpu(ipi_to_irq, cpu)[ipi];
+ if (irq == -1) {
+ irq = find_unbound_irq();
+ if (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;
@@ -369,6 +417,28 @@
}
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);
@@ -376,6 +446,14 @@
}
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
* the event number to an irq, and feed it into do_IRQ() for