xen: implement save/restore
This patch implements Xen save/restore and migration.
Saving is triggered via xenbus, which is polled in
drivers/xen/manage.c. When a suspend request comes in, the kernel
prepares itself for saving by:
1 - Freeze all processes. This is primarily to prevent any
partially-completed pagetable updates from confusing the suspend
process. If CONFIG_PREEMPT isn't defined, then this isn't necessary.
2 - Suspend xenbus and other devices
3 - Stop_machine, to make sure all the other vcpus are quiescent. The
Xen tools require the domain to run its save off vcpu0.
4 - Within the stop_machine state, it pins any unpinned pgds (under
construction or destruction), performs canonicalizes various other
pieces of state (mostly converting mfns to pfns), and finally
5 - Suspend the domain
Restore reverses the steps used to save the domain, ending when all
the frozen processes are thawed.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 70375a6..73d78dc 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -674,6 +674,89 @@
return ret;
}
+static void restore_cpu_virqs(unsigned int cpu)
+{
+ struct evtchn_bind_virq bind_virq;
+ int virq, irq, evtchn;
+
+ for (virq = 0; virq < NR_VIRQS; virq++) {
+ if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
+ continue;
+
+ BUG_ON(irq_info[irq].type != IRQT_VIRQ);
+ BUG_ON(irq_info[irq].index != virq);
+
+ /* Get a new binding from Xen. */
+ bind_virq.virq = virq;
+ bind_virq.vcpu = cpu;
+ if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+ &bind_virq) != 0)
+ BUG();
+ evtchn = bind_virq.port;
+
+ /* Record the new mapping. */
+ evtchn_to_irq[evtchn] = irq;
+ irq_info[irq] = mk_irq_info(IRQT_VIRQ, virq, evtchn);
+ bind_evtchn_to_cpu(evtchn, cpu);
+
+ /* Ready for use. */
+ unmask_evtchn(evtchn);
+ }
+}
+
+static void restore_cpu_ipis(unsigned int cpu)
+{
+ struct evtchn_bind_ipi bind_ipi;
+ int ipi, irq, evtchn;
+
+ for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
+ if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
+ continue;
+
+ BUG_ON(irq_info[irq].type != IRQT_IPI);
+ BUG_ON(irq_info[irq].index != ipi);
+
+ /* Get a new binding from Xen. */
+ bind_ipi.vcpu = cpu;
+ if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
+ &bind_ipi) != 0)
+ BUG();
+ evtchn = bind_ipi.port;
+
+ /* Record the new mapping. */
+ evtchn_to_irq[evtchn] = irq;
+ irq_info[irq] = mk_irq_info(IRQT_IPI, ipi, evtchn);
+ bind_evtchn_to_cpu(evtchn, cpu);
+
+ /* Ready for use. */
+ unmask_evtchn(evtchn);
+
+ }
+}
+
+void xen_irq_resume(void)
+{
+ unsigned int cpu, irq, evtchn;
+
+ init_evtchn_cpu_bindings();
+
+ /* New event-channel space is not 'live' yet. */
+ for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
+ mask_evtchn(evtchn);
+
+ /* No IRQ <-> event-channel mappings. */
+ for (irq = 0; irq < NR_IRQS; irq++)
+ irq_info[irq].evtchn = 0; /* zap event-channel binding */
+
+ for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
+ evtchn_to_irq[evtchn] = -1;
+
+ for_each_possible_cpu(cpu) {
+ restore_cpu_virqs(cpu);
+ restore_cpu_ipis(cpu);
+ }
+}
+
static struct irq_chip xen_dynamic_chip __read_mostly = {
.name = "xen-dyn",
.mask = disable_dynirq,