1 files changed, 63 insertions, 7 deletions

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index db8f506817f0..d659480125f0 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -29,6 +29,7 @@
 #include <linux/bootmem.h>
 #include <linux/slab.h>
 
+#include <asm/desc.h>
 #include <asm/ptrace.h>
 #include <asm/irq.h>
 #include <asm/idle.h>
@@ -36,10 +37,14 @@
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
 
+#include <xen/xen.h>
+#include <xen/hvm.h>
 #include <xen/xen-ops.h>
 #include <xen/events.h>
 #include <xen/interface/xen.h>
 #include <xen/interface/event_channel.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/hvm/params.h>
 
 /*
  * This lock protects updates to the following mapping and reference-count
@@ -617,17 +622,13 @@ static DEFINE_PER_CPU(unsigned, xed_nesting_count);
  * a bitset of words which contain pending event bits.  The second
  * level is a bitset of pending events themselves.
  */
-void xen_evtchn_do_upcall(struct pt_regs *regs)
+static void __xen_evtchn_do_upcall(void)
 {
         int cpu = get_cpu();
-        struct pt_regs *old_regs = set_irq_regs(regs);
         struct shared_info *s = HYPERVISOR_shared_info;
         struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
         unsigned count;
 
-        exit_idle();
-        irq_enter();
-
         do {
                 unsigned long pending_words;
 
@@ -667,10 +668,26 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
         } while(count != 1);
 
 out:
+
+        put_cpu();
+}
+
+void xen_evtchn_do_upcall(struct pt_regs *regs)
+{
+        struct pt_regs *old_regs = set_irq_regs(regs);
+
+        exit_idle();
+        irq_enter();
+
+        __xen_evtchn_do_upcall();
+
         irq_exit();
         set_irq_regs(old_regs);
+}
 
-        put_cpu();
+void xen_hvm_evtchn_do_upcall(void)
+{
+        __xen_evtchn_do_upcall();
 }
 
 /* Rebind a new event channel to an existing irq. */
@@ -933,6 +950,40 @@ static struct irq_chip xen_dynamic_chip __read_mostly = {
         .retrigger      = retrigger_dynirq,
 };
 
+int xen_set_callback_via(uint64_t via)
+{
+        struct xen_hvm_param a;
+        a.domid = DOMID_SELF;
+        a.index = HVM_PARAM_CALLBACK_IRQ;
+        a.value = via;
+        return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
+}
+EXPORT_SYMBOL_GPL(xen_set_callback_via);
+
+/* Vector callbacks are better than PCI interrupts to receive event
+ * channel notifications because we can receive vector callbacks on any
+ * vcpu and we don't need PCI support or APIC interactions. */
+void xen_callback_vector(void)
+{
+        int rc;
+        uint64_t callback_via;
+        if (xen_have_vector_callback) {
+                callback_via = HVM_CALLBACK_VECTOR(XEN_HVM_EVTCHN_CALLBACK);
+                rc = xen_set_callback_via(callback_via);
+                if (rc) {
+                        printk(KERN_ERR "Request for Xen HVM callback vector"
+                                        " failed.\n");
+                        xen_have_vector_callback = 0;
+                        return;
+                }
+                printk(KERN_INFO "Xen HVM callback vector for event delivery is "
+                                "enabled\n");
+                /* in the restore case the vector has already been allocated */
+                if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
+                        alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, xen_hvm_callback_vector);
+        }
+}
+
 void __init xen_init_IRQ(void)
 {
         int i;
@@ -947,5 +998,10 @@ void __init xen_init_IRQ(void)
         for (i = 0; i < NR_EVENT_CHANNELS; i++)
                 mask_evtchn(i);
 
-        irq_ctx_init(smp_processor_id());
+        if (xen_hvm_domain()) {
+                xen_callback_vector();
+                native_init_IRQ();
+        } else {
+                irq_ctx_init(smp_processor_id());
+        }
 }