KVM: x86/xen: Add event channel interrupt vector upcall

[linux-2.6-microblaze.git] / arch / x86 / kvm / xen.c

diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index bd34322..39a7ffc 100644 (file)
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -61,6 +61,44 @@ out:
        return ret;
 }
 
+int __kvm_xen_has_interrupt(struct kvm_vcpu *v)
+{
+       u8 rc = 0;
+
+       /*
+        * If the global upcall vector (HVMIRQ_callback_vector) is set and
+        * the vCPU's evtchn_upcall_pending flag is set, the IRQ is pending.
+        */
+       struct gfn_to_hva_cache *ghc = &v->arch.xen.vcpu_info_cache;
+       struct kvm_memslots *slots = kvm_memslots(v->kvm);
+       unsigned int offset = offsetof(struct vcpu_info, evtchn_upcall_pending);
+
+       /* No need for compat handling here */
+       BUILD_BUG_ON(offsetof(struct vcpu_info, evtchn_upcall_pending) !=
+                    offsetof(struct compat_vcpu_info, evtchn_upcall_pending));
+       BUILD_BUG_ON(sizeof(rc) !=
+                    sizeof(((struct vcpu_info *)0)->evtchn_upcall_pending));
+       BUILD_BUG_ON(sizeof(rc) !=
+                    sizeof(((struct compat_vcpu_info *)0)->evtchn_upcall_pending));
+
+       /*
+        * For efficiency, this mirrors the checks for using the valid
+        * cache in kvm_read_guest_offset_cached(), but just uses
+        * __get_user() instead. And falls back to the slow path.
+        */
+       if (likely(slots->generation == ghc->generation &&
+                  !kvm_is_error_hva(ghc->hva) && ghc->memslot)) {
+               /* Fast path */
+               __get_user(rc, (u8 __user *)ghc->hva + offset);
+       } else {
+               /* Slow path */
+               kvm_read_guest_offset_cached(v->kvm, ghc, &rc, offset,
+                                            sizeof(rc));
+       }
+
+       return rc;
+}
+
 int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
 {
        int r = -ENOENT;
@@ -83,6 +121,16 @@ int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
                r = kvm_xen_shared_info_init(kvm, data->u.shared_info.gfn);
                break;
 
+
+       case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
+               if (data->u.vector < 0x10)
+                       r = -EINVAL;
+               else {
+                       kvm->arch.xen.upcall_vector = data->u.vector;
+                       r = 0;
+               }
+               break;
+
        default:
                break;
        }
@@ -110,6 +158,11 @@ int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data)
                }
                break;
 
+       case KVM_XEN_ATTR_TYPE_UPCALL_VECTOR:
+               data->u.vector = kvm->arch.xen.upcall_vector;
+               r = 0;
+               break;
+
        default:
                break;
        }