[RFC PATCH 11/12] kvm: Add daxfd support for supported flags

[Dave Jiang <dave.jiang@intel.com>]

Add supported flags for daxfd similar to what memfd does.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 include/linux/kvm_host.h | 7 +++++++
 include/uapi/linux/kvm.h | 4 ++++
 virt/kvm/kvm_main.c      | 6 ++++++
 3 files changed, 17 insertions(+)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ffd0381ba079..1427ff41cfc9 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -743,6 +743,13 @@ static inline u64 kvm_gmem_get_supported_flags(struct kvm *kvm)
 }
 #endif
 
+#ifdef CONFIG_KVM_GUEST_DAXFD
+static inline u64 kvm_dax_get_supported_flags(struct kvm *kvm)
+{
+	return GUEST_MEMFD_FLAG_MMAP;
+}
+#endif
+
 #ifndef kvm_arch_has_readonly_mem
 static inline bool kvm_arch_has_readonly_mem(struct kvm *kvm)
 {
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index dddb781b0507..2ae3e1cdcee5 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -51,6 +51,7 @@ struct kvm_userspace_memory_region2 {
 #define KVM_MEM_LOG_DIRTY_PAGES	(1UL << 0)
 #define KVM_MEM_READONLY	(1UL << 1)
 #define KVM_MEM_GUEST_MEMFD	(1UL << 2)
+#define KVM_MEM_GUEST_DAXFD	(1UL << 3)
 
 /* for KVM_IRQ_LINE */
 struct kvm_irq_level {
@@ -974,6 +975,8 @@ struct kvm_enable_cap {
 #define KVM_CAP_GUEST_MEMFD_FLAGS 244
 #define KVM_CAP_ARM_SEA_TO_USER 245
 #define KVM_CAP_S390_USER_OPEREXEC 246
+#define KVM_CAP_GUEST_DAXFD 247
+#define KVM_CAP_GUEST_DAXFD_FLAGS 248
 
 struct kvm_irq_routing_irqchip {
 	__u32 irqchip;
@@ -1612,6 +1615,7 @@ struct kvm_memory_attributes {
 #define KVM_CREATE_GUEST_MEMFD	_IOWR(KVMIO,  0xd4, struct kvm_create_guest_memfd)
 #define GUEST_MEMFD_FLAG_MMAP		(1ULL << 0)
 #define GUEST_MEMFD_FLAG_INIT_SHARED	(1ULL << 1)
+#define GUEST_DAXFD_FLAG_MMAP		(1ULL << 2)
 
 struct kvm_create_guest_memfd {
 	__u64 size;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5b5b69c97665..82d9fb65e149 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -4952,6 +4952,12 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
 		return 1;
 	case KVM_CAP_GUEST_MEMFD_FLAGS:
 		return kvm_gmem_get_supported_flags(kvm);
+#endif
+#ifdef CONFIG_KVM_GUEST_DAXFD
+	case KVM_CAP_GUEST_DAXFD:
+		return 1;
+	case KVM_CAP_GUEST_DAXFD_FLAGS:
+		return kvm_dax_get_supported_flags(kvm);
 #endif
 	default:
 		break;
-- 
2.53.0