[RFC PATCH 17/39] KVM: selftests: Add basic selftests for hugetlb-backed guest_memfd

Ackerley Tng
2024-09-10T23:45:02Z

Add tests for 2MB and 1GB page sizes, and update the invalid flags
test for the new KVM_GUEST_MEMFD_HUGETLB flag.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>

---
.../testing/selftests/kvm/guest_memfd_test.c | 45 ++++++++++++++-----
1 file changed, 35 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/guest_memfd_test.c b/tools/testing/selftests/kvm/guest_memfd_test.c
index ba0c8e996035..3618ce06663e 100644
--- a/tools/testing/selftests/kvm/guest_memfd_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_test.c
@@ -13,6 +13,7 @@

#include <linux/bitmap.h>
#include <linux/falloc.h>
+#include <linux/kvm.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
@@ -122,6 +123,7 @@ static void test_invalid_punch_hole(int fd, size_t page_size, size_t total_size)

static void test_create_guest_memfd_invalid(struct kvm_vm *vm)
{
+ uint64_t valid_flags = KVM_GUEST_MEMFD_HUGETLB;
size_t page_size = getpagesize();
uint64_t flag;
size_t size;
@@ -135,6 +137,9 @@ static void test_create_guest_memfd_invalid(struct kvm_vm *vm)
}

for (flag = 0; flag; flag <<= 1) {
+ if (flag & valid_flags)
+ continue;
+
fd = __vm_create_guest_memfd(vm, page_size, flag);
TEST_ASSERT(fd == -1 && errno == EINVAL,
"guest_memfd() with flag '0x%lx' should fail with EINVAL",
@@ -170,24 +175,16 @@ static void test_create_guest_memfd_multiple(struct kvm_vm *vm)
close(fd1);
}

-int main(int argc, char *argv[])
+static void test_guest_memfd(struct kvm_vm *vm, uint32_t flags, size_t page_size)
{
- size_t page_size;
size_t total_size;
int fd;
- struct kvm_vm *vm;

TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD));

- page_size = getpagesize();
total_size = page_size * 4;

- vm = vm_create_barebones();
-
- test_create_guest_memfd_invalid(vm);
- test_create_guest_memfd_multiple(vm);
-
- fd = vm_create_guest_memfd(vm, total_size, 0);
+ fd = vm_create_guest_memfd(vm, total_size, flags);

test_file_read_write(fd);
test_mmap(fd, page_size);
@@ -197,3 +194,31 @@ int main(int argc, char *argv[])

close(fd);
}
+
+int main(int argc, char *argv[])
+{
+ struct kvm_vm *vm;
+
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_GUEST_MEMFD));
+
+ vm = vm_create_barebones();
+
+ test_create_guest_memfd_invalid(vm);
+ test_create_guest_memfd_multiple(vm);
+
+ printf("Test guest_memfd with 4K pages\n");
+ test_guest_memfd(vm, 0, getpagesize());
+ printf("\tPASSED\n");
+
+ printf("Test guest_memfd with 2M pages\n");
+ test_guest_memfd(vm, KVM_GUEST_MEMFD_HUGETLB | KVM_GUEST_MEMFD_HUGE_2MB,
+ 2UL << 20);
+ printf("\tPASSED\n");
+
+ printf("Test guest_memfd with 1G pages\n");
+ test_guest_memfd(vm, KVM_GUEST_MEMFD_HUGETLB | KVM_GUEST_MEMFD_HUGE_1GB,
+ 1UL << 30);
+ printf("\tPASSED\n");
+
+ return 0;
+}
--
2.46.0.598.g6f2099f65c-goog