9 files changed, 118 insertions, 7 deletions

diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 8767d99c4f64..e2ca30092557 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -125,6 +125,9 @@
  */
 #define MCE_SELF_VECTOR                 0xeb
 
+/* Xen vector callback to receive events in a HVM domain */
+#define XEN_HVM_EVTCHN_CALLBACK         0xe9
+
 #define NR_VECTORS                       256
 
 #define FPU_IRQ                           13
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S
index cd49141cf153..6b196834a0dd 100644
--- a/arch/x86/kernel/entry_32.S
+++ b/arch/x86/kernel/entry_32.S
@@ -1166,6 +1166,9 @@ ENTRY(xen_failsafe_callback)
 .previous
 ENDPROC(xen_failsafe_callback)
 
+BUILD_INTERRUPT3(xen_hvm_callback_vector, XEN_HVM_EVTCHN_CALLBACK,
+                xen_evtchn_do_upcall)
+
 #endif  /* CONFIG_XEN */
 
 #ifdef CONFIG_FUNCTION_TRACER
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 0697ff139837..490ae2bb18a8 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1329,6 +1329,9 @@ ENTRY(xen_failsafe_callback)
         CFI_ENDPROC
 END(xen_failsafe_callback)
 
+apicinterrupt XEN_HVM_EVTCHN_CALLBACK \
+        xen_hvm_callback_vector xen_evtchn_do_upcall
+
 #endif /* CONFIG_XEN */
 
 /*
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 09b36e9d507a..b211a04c4b2c 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -11,6 +11,7 @@
  * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
  */
 
+#include <linux/cpu.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/smp.h>
@@ -38,6 +39,7 @@
 #include <xen/interface/memory.h>
 #include <xen/features.h>
 #include <xen/page.h>
+#include <xen/hvm.h>
 #include <xen/hvc-console.h>
 
 #include <asm/paravirt.h>
@@ -80,6 +82,8 @@ struct shared_info xen_dummy_shared_info;
 void *xen_initial_gdt;
 
 RESERVE_BRK(shared_info_page_brk, PAGE_SIZE);
+__read_mostly int xen_have_vector_callback;
+EXPORT_SYMBOL_GPL(xen_have_vector_callback);
 
 /*
  * Point at some empty memory to start with. We map the real shared_info
@@ -1277,6 +1281,24 @@ static void __init init_shared_info(void)
         per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];
 }
 
+static int __cpuinit xen_hvm_cpu_notify(struct notifier_block *self,
+                                    unsigned long action, void *hcpu)
+{
+        int cpu = (long)hcpu;
+        switch (action) {
+        case CPU_UP_PREPARE:
+                per_cpu(xen_vcpu, cpu) = &HYPERVISOR_shared_info->vcpu_info[cpu];
+                break;
+        default:
+                break;
+        }
+        return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata xen_hvm_cpu_notifier = {
+        .notifier_call  = xen_hvm_cpu_notify,
+};
+
 static void __init xen_hvm_guest_init(void)
 {
         int r;
@@ -1287,6 +1309,12 @@ static void __init xen_hvm_guest_init(void)
                 return;
 
         init_shared_info();
+
+        if (xen_feature(XENFEAT_hvm_callback_vector))
+                xen_have_vector_callback = 1;
+        register_cpu_notifier(&xen_hvm_cpu_notifier);
+        have_vcpu_info_placement = 0;
+        x86_init.irqs.intr_init = xen_init_IRQ;
 }
 
 static bool __init xen_hvm_platform(void)
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index f9153a300bce..0d0e0e6a7479 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -38,6 +38,8 @@ void xen_enable_sysenter(void);
 void xen_enable_syscall(void);
 void xen_vcpu_restore(void);
 
+void xen_callback_vector(void);
+
 void __init xen_build_dynamic_phys_to_machine(void);
 
 void xen_init_irq_ops(void);
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());
+        }
 }
diff --git a/include/xen/events.h b/include/xen/events.h
index e68d59a90ca8..a15d93262e30 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -56,4 +56,11 @@ void xen_poll_irq(int irq);
 /* Determine the IRQ which is bound to an event channel */
 unsigned irq_from_evtchn(unsigned int evtchn);
 
+/* Xen HVM evtchn vector callback */
+extern void xen_hvm_callback_vector(void);
+extern int xen_have_vector_callback;
+int xen_set_callback_via(uint64_t via);
+void xen_evtchn_do_upcall(struct pt_regs *regs);
+void xen_hvm_evtchn_do_upcall(void);
+
 #endif  /* _XEN_EVENTS_H */
diff --git a/include/xen/hvm.h b/include/xen/hvm.h
index 5dfe8fb86e67..b193fa2f9fdd 100644
--- a/include/xen/hvm.h
+++ b/include/xen/hvm.h
@@ -3,6 +3,7 @@
 #define XEN_HVM_H__
 
 #include <xen/interface/hvm/params.h>
+#include <asm/xen/hypercall.h>
 
 static inline int hvm_get_parameter(int idx, uint64_t *value)
 {
@@ -21,4 +22,9 @@ static inline int hvm_get_parameter(int idx, uint64_t *value)
         return r;
 }
 
+#define HVM_CALLBACK_VIA_TYPE_VECTOR 0x2
+#define HVM_CALLBACK_VIA_TYPE_SHIFT 56
+#define HVM_CALLBACK_VECTOR(x) (((uint64_t)HVM_CALLBACK_VIA_TYPE_VECTOR)<<\
+                HVM_CALLBACK_VIA_TYPE_SHIFT | (x))
+
 #endif /* XEN_HVM_H__ */
diff --git a/include/xen/interface/features.h b/include/xen/interface/features.h
index f51b6413b054..8ab08b91bf6f 100644
--- a/include/xen/interface/features.h
+++ b/include/xen/interface/features.h
@@ -41,6 +41,9 @@
 /* x86: Does this Xen host support the MMU_PT_UPDATE_PRESERVE_AD hypercall? */
 #define XENFEAT_mmu_pt_update_preserve_ad  5
 
+/* x86: Does this Xen host support the HVM callback vector type? */
+#define XENFEAT_hvm_callback_vector        8
+
 #define XENFEAT_NR_SUBMAPS 1
 
 #endif /* __XEN_PUBLIC_FEATURES_H__ */