X86: Handle Hyper-V vmbus interrupts as special hypervisor interrupts

Starting with win8, vmbus interrupts can be delivered on any VCPU in the guest
and furthermore can be concurrently active on multiple VCPUs. Support this
interrupt delivery model by setting up a separate IDT entry for Hyper-V vmbus.
interrupts. I would like to thank Jan Beulich <JBeulich@suse.com> and
Thomas Gleixner <tglx@linutronix.de>, for their help.

In this version of the patch, based on the feedback, I have merged the IDT
vector for Xen and Hyper-V and made the necessary adjustments. Furhermore,
based on Jan's feedback I have added the necessary compilation switches.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Link: http://lkml.kernel.org/r/1359940959-32168-3-git-send-email-kys@microsoft.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 74d77dfa5f63..22f77c5f6012 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1787,7 +1787,7 @@ 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);
+                callback_via = HVM_CALLBACK_VECTOR(HYPERVISOR_CALLBACK_VECTOR);
                 rc = xen_set_callback_via(callback_via);
                 if (rc) {
                         printk(KERN_ERR "Request for Xen HVM callback vector"
@@ -1798,8 +1798,9 @@ void xen_callback_vector(void)
                 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);
+                if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
+                        alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
+                                        xen_hvm_callback_vector);
         }
 }
 #else