[RFC PATCH v2 31/37] KVM: selftests: Provide common function to set memory attributes

From: Ackerley Tng

Date: Mon Feb 02 2026 - 17:40:37 EST


From: Sean Christopherson <seanjc@xxxxxxxxxx>

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.

Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
Co-developed-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
.../testing/selftests/kvm/include/kvm_util.h | 44 ++++++++++++++-----
1 file changed, 32 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index b370b70442e8..33905f2ed5c9 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -433,18 +433,6 @@ static inline void vm_set_memory_attributes(struct kvm_vm *vm, uint64_t gpa,
vm_ioctl(vm, KVM_SET_MEMORY_ATTRIBUTES2, &attr);
}

-static inline void vm_mem_set_private(struct kvm_vm *vm, uint64_t gpa,
- uint64_t size)
-{
- vm_set_memory_attributes(vm, gpa, size, KVM_MEMORY_ATTRIBUTE_PRIVATE);
-}
-
-static inline void vm_mem_set_shared(struct kvm_vm *vm, uint64_t gpa,
- uint64_t size)
-{
- vm_set_memory_attributes(vm, gpa, size, 0);
-}
-
static inline int __gmem_set_memory_attributes(int fd, loff_t offset,
uint64_t size,
uint64_t attributes,
@@ -508,6 +496,38 @@ static inline void gmem_set_shared(int fd, loff_t offset, uint64_t size)
gmem_set_memory_attributes(fd, offset, size, 0);
}

+static inline void vm_mem_set_memory_attributes(struct kvm_vm *vm, uint64_t gpa,
+ uint64_t size, uint64_t attrs)
+{
+ if (kvm_has_gmem_attributes) {
+ uint64_t end = gpa + size;
+ uint64_t addr, len;
+ off_t fd_offset;
+ 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, uint64_t gpa,
+ uint64_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, uint64_t gpa,
+ uint64_t size)
+{
+ vm_mem_set_memory_attributes(vm, gpa, size, 0);
+}
+
void vm_guest_mem_fallocate(struct kvm_vm *vm, uint64_t gpa, uint64_t size,
bool punch_hole);

--
2.53.0.rc1.225.gd81095ad13-goog