[PATCH RFC v5 33/53] KVM: selftests: Add helpers for calling ioctls on guest_memfd

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

From: Sean Christopherson <seanjc@google.com>

Add helper functions to kvm_util.h to support calling ioctls, specifically
KVM_SET_MEMORY_ATTRIBUTES2, on a guest_memfd file descriptor.

Introduce gmem_ioctl() and __gmem_ioctl() macros, modeled after the
existing vm_ioctl() helpers, to provide a standard way to call ioctls
on a guest_memfd.

Add gmem_set_memory_attributes() and its derivatives (gmem_set_private(),
gmem_set_shared()) to set memory attributes on a guest_memfd region.
Also provide "__" variants that return the ioctl error code instead of
aborting the test. These helpers will be used by upcoming guest_memfd
tests.

To avoid code duplication, factor out the check for supported memory
attributes into a new macro, TEST_ASSERT_SUPPORTED_ATTRIBUTES, and use
it in both the existing vm_set_memory_attributes() and the new
gmem_set_memory_attributes() helpers.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 98 +++++++++++++++++++++++---
 1 file changed, 90 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index fb54694e6568b..62d917a2d2b19 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -392,6 +392,16 @@ static __always_inline void static_assert_is_vcpu(struct kvm_vcpu *vcpu) { }
 	__TEST_ASSERT_VM_VCPU_IOCTL(!ret, #cmd, ret, (vcpu)->vm);	\
 })
 
+#define __gmem_ioctl(gmem_fd, cmd, arg)				\
+	kvm_do_ioctl(gmem_fd, cmd, arg)
+
+#define gmem_ioctl(gmem_fd, cmd, arg)				\
+({								\
+	int ret = __gmem_ioctl(gmem_fd, cmd, arg);		\
+								\
+	TEST_ASSERT(!ret, __KVM_IOCTL_ERROR(#cmd, ret));	\
+})
+
 /*
  * Looks up and returns the value corresponding to the capability
  * (KVM_CAP_*) given by cap.
@@ -418,8 +428,16 @@ static inline void vm_enable_cap(struct kvm_vm *vm, u32 cap, u64 arg0)
 	vm_ioctl(vm, KVM_ENABLE_CAP, &enable_cap);
 }
 
+/*
+ * KVM_SET_MEMORY_ATTRIBUTES{,2} overwrites _all_ attributes.  These
+ * flows need significant enhancements to support multiple attributes.
+ */
+#define TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes)				\
+	TEST_ASSERT(!(attributes) || (attributes) == KVM_MEMORY_ATTRIBUTE_PRIVATE,	\
+		    "Update me to support multiple attributes!")
+
 static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
-					    u64 size, u64 attributes)
+					    size_t size, u64 attributes)
 {
 	struct kvm_memory_attributes attr = {
 		.attributes = attributes,
@@ -428,17 +446,11 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
 		.flags = 0,
 	};
 
-	/*
-	 * KVM_SET_MEMORY_ATTRIBUTES overwrites _all_ attributes.  These flows
-	 * need significant enhancements to support multiple attributes.
-	 */
-	TEST_ASSERT(!attributes || attributes == KVM_MEMORY_ATTRIBUTE_PRIVATE,
-		    "Update me to support multiple attributes!");
+	TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
 
 	vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
 }
 
-
 static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
 				      u64 size)
 {
@@ -451,6 +463,76 @@ static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
 	vm_set_memory_attributes(vm, gpa, size, 0);
 }
 
+static inline int __gmem_set_memory_attributes(int fd, loff_t offset,
+					       size_t size, u64 attributes,
+					       loff_t *error_offset,
+					       u64 flags)
+{
+	struct kvm_memory_attributes2 attr = {
+		.attributes = attributes,
+		.offset = offset,
+		.size = size,
+		.flags = flags,
+		.error_offset = error_offset ? *error_offset : 0,
+	};
+	int r;
+
+	TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
+
+	r = __gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
+
+	/* Copy error_offset regardless of r so caller can check. */
+	if (error_offset)
+		*error_offset = attr.error_offset;
+
+	return r;
+}
+
+static inline int __gmem_set_private(int fd, loff_t offset, size_t size,
+				     loff_t *error_offset, u64 flags)
+{
+	return __gmem_set_memory_attributes(fd, offset, size,
+					    KVM_MEMORY_ATTRIBUTE_PRIVATE,
+					    error_offset, flags);
+}
+
+static inline int __gmem_set_shared(int fd, loff_t offset, size_t size,
+				    loff_t *error_offset, u64 flags)
+{
+	return __gmem_set_memory_attributes(fd, offset, size, 0,
+					    error_offset, flags);
+}
+
+static inline void gmem_set_memory_attributes(int fd, loff_t offset,
+					      size_t size, u64 attributes,
+					      u64 flags)
+{
+	struct kvm_memory_attributes2 attr = {
+		.attributes = attributes,
+		.offset = offset,
+		.size = size,
+		.flags = flags,
+	};
+
+	TEST_ASSERT_SUPPORTED_ATTRIBUTES(attributes);
+
+	__TEST_REQUIRE(kvm_check_cap(KVM_CAP_GUEST_MEMFD_MEMORY_ATTRIBUTES) > 0,
+		       "No valid attributes for guest_memfd ioctl!");
+
+	gmem_ioctl(fd, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
+}
+
+static inline void gmem_set_private(int fd, loff_t offset, size_t size, u64 flags)
+{
+	gmem_set_memory_attributes(fd, offset, size,
+				   KVM_MEMORY_ATTRIBUTE_PRIVATE, flags);
+}
+
+static inline void gmem_set_shared(int fd, loff_t offset, size_t size, u64 flags)
+{
+	gmem_set_memory_attributes(fd, offset, size, 0, flags);
+}
+
 void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
 			    bool punch_hole);
 

-- 
2.54.0.545.g6539524ca2-goog