KVM: selftests: Refactor UAPI tests into dedicated function

Move steal time UAPI tests from steal_time_init() into a separate
check_steal_time_uapi() function for better code organization and
maintainability.

Previously, x86 and ARM64 architectures performed UAPI validation
tests within steal_time_init(), mixing initialization logic with
uapi tests.

Changes by architecture:
x86_64:
  - Extract MSR reserved bits test from steal_time_init()
  - Move to check_steal_time_uapi() which tests that setting
    MSR_KVM_STEAL_TIME with KVM_STEAL_RESERVED_MASK fails
ARM64:
  - Extract three UAPI tests from steal_time_init():
     Device attribute support check
     Misaligned IPA rejection (EINVAL)
     Duplicate IPA setting rejection (EEXIST)
  - Move all tests to check_steal_time_uapi()
RISC-V:
  - Add empty check_steal_time_uapi() stub for future use
  - No changes to steal_time_init() (had no tests to extract)

The new check_steal_time_uapi() function:
  - Is called once before the per-VCPU test loop

No functional change intended.

Suggested-by: Andrew Jones <andrew.jones@oss.qualcomm.com>
Signed-off-by: Jiakai Xu <xujiakai2025@iscas.ac.cn>
Signed-off-by: Jiakai Xu <jiakaiPeanut@gmail.com>
Reviewed-by: Andrew Jones <andrew.jones@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20260303010859.1763177-3-xujiakai2025@iscas.ac.cn
Signed-off-by: Anup Patel <anup@brainfault.org>

1 files changed, 51 insertions, 16 deletions

diff --git a/tools/testing/selftests/kvm/steal_time.c b/tools/testing/selftests/kvm/steal_time.c
index 7be8adfe5dd3..8e4d7c13b598 100644
--- a/tools/testing/selftests/kvm/steal_time.c
+++ b/tools/testing/selftests/kvm/steal_time.c
@@ -69,16 +69,10 @@ static bool is_steal_time_supported(struct kvm_vcpu *vcpu)
 
 static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i)
 {
-	int ret;
-
 	/* ST_GPA_BASE is identity mapped */
 	st_gva[i] = (void *)(ST_GPA_BASE + i * STEAL_TIME_SIZE);
 	sync_global_to_guest(vcpu->vm, st_gva[i]);
 
-	ret = _vcpu_set_msr(vcpu, MSR_KVM_STEAL_TIME,
-			    (ulong)st_gva[i] | KVM_STEAL_RESERVED_MASK);
-	TEST_ASSERT(ret == 0, "Bad GPA didn't fail");
-
 	vcpu_set_msr(vcpu, MSR_KVM_STEAL_TIME, (ulong)st_gva[i] | KVM_MSR_ENABLED);
 }
 
@@ -99,6 +93,21 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
 			st->pad[8], st->pad[9], st->pad[10]);
 }
 
+static void check_steal_time_uapi(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	int ret;
+
+	vm = vm_create_with_one_vcpu(&vcpu, NULL);
+
+	ret = _vcpu_set_msr(vcpu, MSR_KVM_STEAL_TIME,
+			    (ulong)ST_GPA_BASE | KVM_STEAL_RESERVED_MASK);
+	TEST_ASSERT(ret == 0, "Bad GPA didn't fail");
+
+	kvm_vm_free(vm);
+}
+
 #elif defined(__aarch64__)
 
 /* PV_TIME_ST must have 64-byte alignment */
@@ -170,7 +179,6 @@ static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i)
 {
 	struct kvm_vm *vm = vcpu->vm;
 	uint64_t st_ipa;
-	int ret;
 
 	struct kvm_device_attr dev = {
 		.group = KVM_ARM_VCPU_PVTIME_CTRL,
@@ -178,21 +186,12 @@ static void steal_time_init(struct kvm_vcpu *vcpu, uint32_t i)
 		.addr = (uint64_t)&st_ipa,
 	};
 
-	vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &dev);
-
 	/* ST_GPA_BASE is identity mapped */
 	st_gva[i] = (void *)(ST_GPA_BASE + i * STEAL_TIME_SIZE);
 	sync_global_to_guest(vm, st_gva[i]);
 
-	st_ipa = (ulong)st_gva[i] | 1;
-	ret = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
-	TEST_ASSERT(ret == -1 && errno == EINVAL, "Bad IPA didn't report EINVAL");
-
 	st_ipa = (ulong)st_gva[i];
 	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
-
-	ret = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
-	TEST_ASSERT(ret == -1 && errno == EEXIST, "Set IPA twice without EEXIST");
 }
 
 static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
@@ -205,6 +204,36 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
 	ksft_print_msg("    st_time: %ld\n", st->st_time);
 }
 
+static void check_steal_time_uapi(void)
+{
+	struct kvm_vm *vm;
+	struct kvm_vcpu *vcpu;
+	uint64_t st_ipa;
+	int ret;
+
+	vm = vm_create_with_one_vcpu(&vcpu, NULL);
+
+	struct kvm_device_attr dev = {
+		.group = KVM_ARM_VCPU_PVTIME_CTRL,
+		.attr = KVM_ARM_VCPU_PVTIME_IPA,
+		.addr = (uint64_t)&st_ipa,
+	};
+
+	vcpu_ioctl(vcpu, KVM_HAS_DEVICE_ATTR, &dev);
+
+	st_ipa = (ulong)ST_GPA_BASE | 1;
+	ret = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
+	TEST_ASSERT(ret == -1 && errno == EINVAL, "Bad IPA didn't report EINVAL");
+
+	st_ipa = (ulong)ST_GPA_BASE;
+	vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
+
+	ret = __vcpu_ioctl(vcpu, KVM_SET_DEVICE_ATTR, &dev);
+	TEST_ASSERT(ret == -1 && errno == EEXIST, "Set IPA twice without EEXIST");
+
+	kvm_vm_free(vm);
+}
+
 #elif defined(__riscv)
 
 /* SBI STA shmem must have 64-byte alignment */
@@ -301,6 +330,10 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
 	pr_info("\n");
 }
 
+static void check_steal_time_uapi(void)
+{
+}
+
 #elif defined(__loongarch__)
 
 /* steal_time must have 64-byte alignment */
@@ -465,6 +498,8 @@ int main(int ac, char **av)
 	TEST_REQUIRE(is_steal_time_supported(vcpus[0]));
 	ksft_set_plan(NR_VCPUS);
 
+	check_steal_time_uapi();
+
 	/* Run test on each VCPU */
 	for (i = 0; i < NR_VCPUS; ++i) {
 		steal_time_init(vcpus[i], i);