From: David Woodhouse <dwmw@xxxxxxxxxxxx>
This adds a KVM_XEN_HVM_EVTCHN_SEND ioctl which allows direct injection
of events given an explicit { vcpu, port, priority } in precisely the
same form that those fields are given in the IRQ routing table.
Userspace is currently able to inject 2-level events purely by setting
the bits in the shared_info and vcpu_info, but FIFO event channels are
harder to deal with; we will need the kernel to take sole ownership of
delivery when we support those.
A patch advertising this feature with a new bit in the KVM_CAP_XEN_HVM
ioctl will be added in a subsequent patch.
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
---
arch/x86/kvm/x86.c | 9 +++++++++
arch/x86/kvm/xen.c | 32 ++++++++++++++++++++++++++++++++
arch/x86/kvm/xen.h | 1 +
include/uapi/linux/kvm.h | 3 +++
4 files changed, 45 insertions(+)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index fd16615cc0f2..a6ba50c9928b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6476,6 +6476,15 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = kvm_xen_hvm_set_attr(kvm, &xha);
break;
}
+ case KVM_XEN_HVM_EVTCHN_SEND: {
+ struct kvm_irq_routing_xen_evtchn uxe;
+
+ r = -EFAULT;
+ if (copy_from_user(&uxe, argp, sizeof(uxe)))
+ goto out;
+ r = kvm_xen_hvm_evtchn_send(kvm, &uxe);
+ break;
+ }
#endif
case KVM_SET_CLOCK:
r = kvm_vm_ioctl_set_clock(kvm, argp);
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index 9c87263a5be2..f0f0011c4617 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c
@@ -1086,6 +1086,38 @@ int kvm_xen_setup_evtchn(struct kvm *kvm,
return 0;
}
+/*
+ * Explicit event sending from userspace with KVM_XEN_HVM_EVTCHN_SEND ioctl.
+ */
+int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *uxe)
+{
+ struct kvm_xen_evtchn e;
+ int ret;
+
+ if (!uxe->port || uxe->port >= max_evtchn_port(kvm))
+ return -EINVAL;
+
+ /* We only support 2 level event channels for now */
+ if (uxe->priority != KVM_IRQ_ROUTING_XEN_EVTCHN_PRIO_2LEVEL)
+ return -EINVAL;
+
+ e.port = uxe->port;
+ e.vcpu_id = uxe->vcpu;
+ e.vcpu_idx = -1;
+ e.priority = uxe->priority;
+
+ ret = kvm_xen_set_evtchn(&e, kvm);
+
+ /*
+ * None of that 'return 1 if it actually got delivered' nonsense.
+ * We don't care if it was masked (-ENOTCONN) either.
+ */
+ if (ret > 0 || ret == -ENOTCONN)
+ ret = 0;
+
+ return ret;
+}
+
void kvm_xen_destroy_vcpu(struct kvm_vcpu *vcpu)
{
kvm_gfn_to_pfn_cache_destroy(vcpu->kvm,
diff --git a/arch/x86/kvm/xen.h b/arch/x86/kvm/xen.h
index e28feb32add6..852286de574e 100644
--- a/arch/x86/kvm/xen.h
+++ b/arch/x86/kvm/xen.h
@@ -20,6 +20,7 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data)
int kvm_xen_vcpu_get_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data);
int kvm_xen_hvm_set_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
int kvm_xen_hvm_get_attr(struct kvm *kvm, struct kvm_xen_hvm_attr *data);
+int kvm_xen_hvm_evtchn_send(struct kvm *kvm, struct kvm_irq_routing_xen_evtchn *evt);
int kvm_xen_write_hypercall_page(struct kvm_vcpu *vcpu, u64 data);
int kvm_xen_hvm_config(struct kvm *kvm, struct kvm_xen_hvm_config *xhc);
void kvm_xen_init_vm(struct kvm *kvm);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d2f1efc3aa35..415d8fe5c624 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1698,6 +1698,9 @@ struct kvm_xen_hvm_attr {
#define KVM_XEN_VCPU_GET_ATTR _IOWR(KVMIO, 0xca, struct kvm_xen_vcpu_attr)
#define KVM_XEN_VCPU_SET_ATTR _IOW(KVMIO, 0xcb, struct kvm_xen_vcpu_attr)
+/* Available with KVM_CAP_XEN_HVM / KVM_XEN_HVM_CONFIG_EVTCHN_SEND */
+#define KVM_XEN_HVM_EVTCHN_SEND _IOW(KVMIO, 0xd0, struct kvm_irq_routing_xen_evtchn)
+
#define KVM_GET_SREGS2 _IOR(KVMIO, 0xcc, struct kvm_sregs2)
#define KVM_SET_SREGS2 _IOW(KVMIO, 0xcd, struct kvm_sregs2)
--
2.33.1
