smp_send_reschedule was exported (via smp_ops) in v2.6.24.
Create a compat function which schedules the IPI to keventd context, 
in case interrupts are disabled, for kernels < 2.6.24.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/kvm/kernel/external-module-compat-comm.h b/kvm/kernel/external-module-compat-comm.h
index c955927..852a8c1 100644
--- a/kvm/kernel/external-module-compat-comm.h
+++ b/kvm/kernel/external-module-compat-comm.h
@@ -116,6 +116,10 @@ int kvm_smp_call_function_single(int cpu, void (*func)(void *info),
 
 #endif
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,28)
+#define nr_cpu_ids NR_CPUS
+#endif
+
 #include <linux/miscdevice.h>
 #ifndef KVM_MINOR
 #define KVM_MINOR 232
@@ -220,6 +224,10 @@ int kvm_smp_call_function_mask(cpumask_t mask, void (*func) (void *info),
 
 #define smp_call_function_mask kvm_smp_call_function_mask
 
+void kvm_smp_send_reschedule(int cpu);
+
+#define smp_send_reschedule kvm_smp_send_reschedule
+
 #endif
 
 /* empty_zero_page isn't exported in all kernels */
diff --git a/kvm/kernel/external-module-compat.c b/kvm/kernel/external-module-compat.c
index 0d858be..ca269cc 100644
--- a/kvm/kernel/external-module-compat.c
+++ b/kvm/kernel/external-module-compat.c
@@ -221,6 +221,58 @@ out:
 	return 0;
 }
 
+#include <linux/workqueue.h>
+
+static void vcpu_kick_intr(void *info)
+{
+}
+
+struct kvm_kick {
+	int cpu;
+	struct work_struct work;
+};
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
+static void kvm_do_smp_call_function(void *data)
+{
+	int me;
+	struct kvm_kick *kvm_kick = data;
+#else
+static void kvm_do_smp_call_function(struct work_struct *work)
+{
+	int me;
+	struct kvm_kick *kvm_kick = container_of(work, struct kvm_kick, work);
+#endif
+	me = get_cpu();
+
+	if (kvm_kick->cpu != me)
+		smp_call_function_single(kvm_kick->cpu, vcpu_kick_intr,
+					 NULL, 0);
+	kfree(kvm_kick);
+	put_cpu();
+}
+
+void kvm_queue_smp_call_function(int cpu)
+{
+	struct kvm_kick *kvm_kick = kmalloc(sizeof(struct kvm_kick), GFP_ATOMIC);
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)
+	INIT_WORK(&kvm_kick->work, kvm_do_smp_call_function, kvm_kick);
+#else
+	INIT_WORK(&kvm_kick->work, kvm_do_smp_call_function);
+#endif
+
+	schedule_work(&kvm_kick->work);
+}
+
+void kvm_smp_send_reschedule(int cpu)
+{
+	if (irqs_disabled()) {
+		kvm_queue_smp_call_function(cpu);
+		return;
+	}
+	smp_call_function_single(cpu, vcpu_kick_intr, NULL, 0);
+}
 #endif
 
 /* manually export hrtimer_init/start/cancel */
diff --git a/kvm/kernel/x86/hack-module.awk b/kvm/kernel/x86/hack-module.awk
index 260eeef..f4d14da 100644
--- a/kvm/kernel/x86/hack-module.awk
+++ b/kvm/kernel/x86/hack-module.awk
@@ -35,6 +35,8 @@ BEGIN { split("INIT_WORK desc_struct ldttss_desc64 desc_ptr " \
 
 { sub(/match->dev->msi_enabled/, "kvm_pcidev_msi_enabled(match->dev)") }
 
+{ sub(/smp_send_reschedule/, "kvm_smp_send_reschedule") }
+
 /^static void __vmx_load_host_state/ {
     vmx_load_host_state = 1
 }