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>

1 files changed, 23 insertions, 4 deletions

diff --git a/include/xen/events.h b/include/xen/events.h
index 77f71c906823..7abe4ddfac54 100644
--- 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.
@@ -18,6 +35,8 @@ int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
  */
 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)
 {
 	struct evtchn_send send = { .port = port };