[PATCH RFC 3/3] kvm: add KVM_CAP_IOEVENTFD_PF capability

["Michael S. Tsirkin" <mst@redhat.com>]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/kvm.h          | 1 +
 arch/x86/kvm/x86.c                | 1 +
 Documentation/virtual/kvm/api.txt | 7 +++++++
 3 files changed, 9 insertions(+)

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 716ad4a..4509aa3 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -817,6 +817,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_DISABLE_QUIRKS 116
 #define KVM_CAP_X86_SMM 117
 #define KVM_CAP_MULTI_ADDRESS_SPACE 118
+#define KVM_CAP_IOEVENTFD_PF 119
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c8015fa..f989453 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2629,6 +2629,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_IRQ_INJECT_STATUS:
 	case KVM_CAP_IOEVENTFD:
 	case KVM_CAP_IOEVENTFD_NO_LENGTH:
+	case KVM_CAP_IOEVENTFD_PF:
 	case KVM_CAP_PIT2:
 	case KVM_CAP_PIT_STATE2:
 	case KVM_CAP_SET_IDENTITY_MAP_ADDR:
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index a7926a9..85a76ad 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -1618,6 +1618,13 @@ The following flags are defined:
 If datamatch flag is set, the event will be signaled only if the written value
 to the registered address is equal to datamatch in struct kvm_ioeventfd.
 
+If KVM_CAP_IOEVENTFD_NO_LENGTH is present, and when DATAMATCH flag
+is clear, len can be set to 0 to match access of any length.
+
+If KVM_CAP_IOEVENTFD_PF is present, and when DATAMATCH flag
+is clear and len is set to 0, the specified address can overlap
+a read-only memory region (as opposed to an MMIO region).
+
 For virtio-ccw devices, addr contains the subchannel id and datamatch the
 virtqueue index.
 
-- 
MST