[PATCH RFC 05/17] KVM: selftests: Add helper to create guest_memfd with a resource file

[Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>]

From: Ackerley Tng <ackerleytng@google.com>

Add a helper to create guest_memfd instances with a resource file
descriptor, and update the existing creation helper to pass a zero
resource file descriptor.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/include/uapi/linux/kvm.h                 |  5 ++++-
 tools/testing/selftests/kvm/include/kvm_util.h | 23 ++++++++++++++++++-----
 2 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/tools/include/uapi/linux/kvm.h b/tools/include/uapi/linux/kvm.h
index 419011097fa8e..66c1f40b50c29 100644
--- a/tools/include/uapi/linux/kvm.h
+++ b/tools/include/uapi/linux/kvm.h
@@ -1654,11 +1654,14 @@ 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_MEMFD_FLAG_USE_RESOURCE	(1ULL << 2)
 
 struct kvm_create_guest_memfd {
 	__u64 size;
 	__u64 flags;
-	__u64 reserved[6];
+	__s32 resource_fd;
+	__u32 pad;
+	__u64 reserved[5];
 };
 
 #define KVM_PRE_FAULT_MEMORY	_IOWR(KVMIO, 0xd5, struct kvm_pre_fault_memory)
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 777fa3dbf88d6..9eeaefe5a1839 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -767,26 +767,39 @@ static inline bool is_smt_on(void)
 
 void vm_create_irqchip(struct kvm_vm *vm);
 
-static inline int __vm_create_guest_memfd(struct kvm_vm *vm, u64 size,
-					  u64 flags)
+static inline int __vm_create_guest_memfd_resource(struct kvm_vm *vm, u64 size,
+						   u64 flags, int resource_fd)
 {
 	struct kvm_create_guest_memfd guest_memfd = {
 		.size = size,
 		.flags = flags,
+		.resource_fd = resource_fd,
 	};
 
 	return __vm_ioctl(vm, KVM_CREATE_GUEST_MEMFD, &guest_memfd);
 }
 
-static inline int vm_create_guest_memfd(struct kvm_vm *vm, u64 size,
-					u64 flags)
+static inline int __vm_create_guest_memfd(struct kvm_vm *vm, u64 size,
+					  u64 flags)
+{
+	return __vm_create_guest_memfd_resource(vm, size, flags, 0);
+}
+
+static inline int vm_create_guest_memfd_resource(struct kvm_vm *vm, u64 size,
+						 u64 flags, int resource_fd)
 {
-	int fd = __vm_create_guest_memfd(vm, size, flags);
+	int fd = __vm_create_guest_memfd_resource(vm, size, flags, resource_fd);
 
 	TEST_ASSERT(fd >= 0, KVM_IOCTL_ERROR(KVM_CREATE_GUEST_MEMFD, fd));
 	return fd;
 }
 
+static inline int vm_create_guest_memfd(struct kvm_vm *vm, u64 size,
+					u64 flags)
+{
+	return vm_create_guest_memfd_resource(vm, size, flags, 0);
+}
+
 void vm_set_user_memory_region(struct kvm_vm *vm, u32 slot, u32 flags,
 			       gpa_t gpa, u64 size, void *hva);
 int __vm_set_user_memory_region(struct kvm_vm *vm, u32 slot, u32 flags,

-- 
2.56.0.rc1.315.gc6ed9934b7-goog