[PATCH v11 15/16] KVM: selftests: stuff vm_mem_backing_src_type into vm_shape

Kalyazin, Nikita
2026-03-17T14:13:35Z

From: Patrick Roy <patrick.roy@linux.dev>

Use one of the padding fields in struct vm_shape to carry an enum
vm_mem_backing_src_type value, to give the option to overwrite the
default of VM_MEM_SRC_ANONYMOUS in __vm_create().

Overwriting this default will allow tests to create VMs where the test
code is backed by mmap'd guest_memfd instead of anonymous memory.

Signed-off-by: Patrick Roy <patrick.roy@linux.dev>
Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>
---
.../testing/selftests/kvm/include/kvm_util.h | 19 ++++++++++---------
tools/testing/selftests/kvm/lib/kvm_util.c | 2 +-
tools/testing/selftests/kvm/lib/x86/sev.c | 1 +
.../selftests/kvm/pre_fault_memory_test.c | 1 +
4 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 056a003a63c0..48b6ee8223aa 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -215,7 +215,7 @@ enum vm_guest_mode {
struct vm_shape {
uint32_t type;
uint8_t mode;
- uint8_t pad0;
+ uint8_t src_type;
uint16_t pad1;
};

@@ -223,14 +223,15 @@ kvm_static_assert(sizeof(struct vm_shape) == sizeof(uint64_t));

#define VM_TYPE_DEFAULT 0

-#define VM_SHAPE(__mode) \
-({ \
- struct vm_shape shape = { \
- .mode = (__mode), \
- .type = VM_TYPE_DEFAULT \
- }; \
- \
- shape; \
+#define VM_SHAPE(__mode) \
+({ \
+ struct vm_shape shape = { \
+ .mode = (__mode), \
+ .type = VM_TYPE_DEFAULT, \
+ .src_type = VM_MEM_SRC_ANONYMOUS \
+ }; \
+ \
+ shape; \
})

extern enum vm_guest_mode vm_mode_default;
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index fa4a2fc236fe..824c94c64864 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -500,7 +500,7 @@ struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus,
if (is_guest_memfd_required(shape))
flags |= KVM_MEM_GUEST_MEMFD;

- vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, flags);
+ vm_userspace_mem_region_add(vm, shape.src_type, 0, 0, nr_pages, flags);
for (i = 0; i < NR_MEM_REGIONS; i++)
vm->memslots[i] = 0;

diff --git a/tools/testing/selftests/kvm/lib/x86/sev.c b/tools/testing/selftests/kvm/lib/x86/sev.c
index c3a9838f4806..d920880e4fc0 100644
--- a/tools/testing/selftests/kvm/lib/x86/sev.c
+++ b/tools/testing/selftests/kvm/lib/x86/sev.c
@@ -164,6 +164,7 @@ struct kvm_vm *vm_sev_create_with_one_vcpu(uint32_t type, void *guest_code,
struct vm_shape shape = {
.mode = VM_MODE_DEFAULT,
.type = type,
+ .src_type = VM_MEM_SRC_ANONYMOUS,
};
struct kvm_vm *vm;
struct kvm_vcpu *cpus[1];
diff --git a/tools/testing/selftests/kvm/pre_fault_memory_test.c b/tools/testing/selftests/kvm/pre_fault_memory_test.c
index 93e603d91311..8a4d5af53fab 100644
--- a/tools/testing/selftests/kvm/pre_fault_memory_test.c
+++ b/tools/testing/selftests/kvm/pre_fault_memory_test.c
@@ -165,6 +165,7 @@ static void __test_pre_fault_memory(unsigned long vm_type, bool private)
const struct vm_shape shape = {
.mode = VM_MODE_DEFAULT,
.type = vm_type,
+ .src_type = VM_MEM_SRC_ANONYMOUS,
};
struct kvm_vcpu *vcpu;
struct kvm_run *run;
--
2.50.1