Thread (154 messages) 154 messages, 12 authors, 2d ago
WARM2d

[PATCH v8 42/46] KVM: selftests: Provide common function to set memory attributes

From: Ackerley Tng via B4 Relay <devnull+ackerleytng.google.com@kernel.org>
Date: 2026-06-19 00:31:51
Also in: b4-sent, kvm, linux-coco, linux-kselftest, linux-mm, linux-trace-kernel, lkml
Subsystem: kernel selftest framework, kernel virtual machine (kvm), the rest · Maintainers: Shuah Khan, Paolo Bonzini, Linus Torvalds

From: Sean Christopherson <seanjc@google.com>

Introduce vm_mem_set_memory_attributes(), which handles setting of memory
attributes for a range of guest physical addresses, regardless of whether
the attributes should be set via guest_memfd or via the memory attributes
at the VM level.

Refactor existing vm_mem_set_{shared,private} functions to use the new
function. Opportunistically update the size parameter to use size_t instead
of u64.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Co-developed-by: Ackerley Tng <redacted>
Signed-off-by: Ackerley Tng <redacted>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 46 +++++++++++++++++++-------
 1 file changed, 34 insertions(+), 12 deletions(-)
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 3a6b1fa7f26ef..db1442da21bb1 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -454,18 +454,6 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
 	vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES, &attr);
 }
 
-static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
-				      u64 size)
-{
-	vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
-}
-
-static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
-				     u64 size)
-{
-	vm_set_memory_attributes(vm, gpa, size, 0);
-}
-
 static inline int __gmem_set_memory_attributes(int fd, u64 offset,
 					       size_t size, u64 attributes,
 					       u64 *error_offset)
@@ -532,6 +520,40 @@ static inline void gmem_set_shared(int fd, u64 offset, size_t size)
 	gmem_set_memory_attributes(fd, offset, size, 0);
 }
 
+static inline void vm_mem_set_memory_attributes(struct kvm_vm *vm, gpa_t gpa,
+						size_t size, u64 attrs)
+{
+	if (kvm_has_gmem_attributes) {
+		gpa_t end = gpa + size;
+		off_t fd_offset;
+		gpa_t addr;
+		size_t len;
+		int fd;
+
+		for (addr = gpa; addr < end; addr += len) {
+			fd = kvm_gpa_to_guest_memfd(vm, addr, &fd_offset, &len);
+			len = min(end - addr, len);
+
+			gmem_set_memory_attributes(fd, fd_offset, len, attrs);
+		}
+	} else {
+		vm_set_memory_attributes(vm, gpa, size, attrs);
+	}
+}
+
+static inline void vm_mem_set_private(struct kvm_vm *vm, gpa_t gpa,
+				      size_t size)
+{
+	vm_mem_set_memory_attributes(vm, gpa, size,
+				     KVM_MEMORY_ATTRIBUTE_PRIVATE);
+}
+
+static inline void vm_mem_set_shared(struct kvm_vm *vm, gpa_t gpa,
+				     size_t size)
+{
+	vm_mem_set_memory_attributes(vm, gpa, size, 0);
+}
+
 void vm_guest_mem_fallocate(struct kvm_vm *vm, gpa_t gpa, u64 size,
 			    bool punch_hole);
 
-- 
2.55.0.rc0.738.g0c8ab3ebcc-goog

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