[PATCH RFC 16/39] KVM: x86: declare Xen HVM evtchn offload capability

[Joao Martins]

Add new capability for event channel support in hypervisor.

Signed-off-by: Joao Martins <joao.m.martins@xxxxxxxxxx>
---
 Documentation/virtual/kvm/api.txt | 9 +++++++++
 arch/x86/kvm/x86.c                | 1 +
 include/uapi/linux/kvm.h          | 3 +++
 3 files changed, 13 insertions(+)

diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c3a1402b76bf..36d9386415fa 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -5037,3 +5037,12 @@ Architectures: x86
 
 This capability indicates that KVM supports Xen HVM guests.
 This includes KVM_IRQ_ROUTING_XEN_EVTCHN as well.
+
+8.23 KVM_CAP_XEN_HVM_EVTCHN
+
+Architectures: x86
+
+This capability indicates KVM's support for the event channel offload.
+Implies support for KVM_IRQ_ROUTING_XEN_EVTCHN irq routing, and
+for attribute KVM_XEN_ATTR_TYPE_EVTCHN in KVM_XEN_HVM_GET_ATTR or
+KVM_XEN_HVM_SET_ATTR.
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e29cefd2dc6a..b1d9045d7989 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3010,6 +3010,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_SET_IDENTITY_MAP_ADDR:
 	case KVM_CAP_XEN_HVM:
 	case KVM_CAP_XEN_HVM_GUEST:
+	case KVM_CAP_XEN_HVM_EVTCHN:
 	case KVM_CAP_VCPU_EVENTS:
 	case KVM_CAP_HYPERV:
 	case KVM_CAP_HYPERV_VAPIC:
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 4eae47a0ef63..1b3ecce5f92e 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1004,6 +1004,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT 166
 #define KVM_CAP_HYPERV_CPUID 167
 #define KVM_CAP_XEN_HVM_GUEST 168
+#define KVM_CAP_XEN_HVM_EVTCHN 169
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1046,6 +1047,7 @@ struct kvm_irq_routing_xen_evtchn {
 #define KVM_IRQ_ROUTING_MSI 2
 #define KVM_IRQ_ROUTING_S390_ADAPTER 3
 #define KVM_IRQ_ROUTING_HV_SINT 4
+/* Available with KVM_CAP_XEN_HVM_EVTCHN */
 #define KVM_IRQ_ROUTING_XEN_EVTCHN 5
 
 struct kvm_irq_routing_entry {
@@ -1506,6 +1508,7 @@ struct kvm_xen_hvm_attr {
 #define KVM_XEN_ATTR_TYPE_VCPU_INFO         0x1
 #define KVM_XEN_ATTR_TYPE_VCPU_TIME_INFO    0x2
 #define KVM_XEN_ATTR_TYPE_VCPU_RUNSTATE     0x3
+/* Available with KVM_CAP_XEN_HVM_EVTCHN */
 #define KVM_XEN_ATTR_TYPE_EVTCHN            0x4
 
 /* Secure Encrypted Virtualization command */
-- 
2.11.0