[PATCH v2] KVM: selftests: Add get featured msrs test case

[Peter Xu <peterx@redhat.com>]

Try to fetch any supported featured msr.  Currently it won't fail, so at least
we can check against valid ones (which should be >0).

This reproduces the issue [1] too by trying to fetch one invalid msr there.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=209845

Signed-off-by: Peter Xu <peterx@redhat.com>
--
v2:
- rename kvm_vm_get_feature_msrs to be prefixed with "_" [Vitaly, Drew]
- drop the fix patch since queued with a better version
---
 .../testing/selftests/kvm/include/kvm_util.h  |  3 +
 tools/testing/selftests/kvm/lib/kvm_util.c    | 14 +++++
 .../testing/selftests/kvm/x86_64/state_test.c | 58 +++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 919e161dd289..1199f2003bee 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -66,6 +66,9 @@ int vm_enable_cap(struct kvm_vm *vm, struct kvm_enable_cap *cap);
 
 struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm);
 struct kvm_vm *_vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm);
+void kvm_vm_get_msr_feature_index_list(struct kvm_vm *vm,
+				       struct kvm_msr_list *list);
+int _kvm_vm_get_feature_msrs(struct kvm_vm *vm, struct kvm_msrs *msrs);
 void kvm_vm_free(struct kvm_vm *vmp);
 void kvm_vm_restart(struct kvm_vm *vmp, int perm);
 void kvm_vm_release(struct kvm_vm *vmp);
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 74776ee228f2..ad81d51fcf53 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -132,6 +132,20 @@ static const struct vm_guest_mode_params vm_guest_mode_params[] = {
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
 	       "Missing new mode params?");
 
+void kvm_vm_get_msr_feature_index_list(struct kvm_vm *vm,
+				       struct kvm_msr_list *list)
+{
+	int r = ioctl(vm->kvm_fd, KVM_GET_MSR_FEATURE_INDEX_LIST, list);
+
+	TEST_ASSERT(r == 0, "KVM_GET_MSR_FEATURE_INDEX_LIST failed: %d\n",
+		    -errno);
+}
+
+int _kvm_vm_get_feature_msrs(struct kvm_vm *vm, struct kvm_msrs *msrs)
+{
+	return ioctl(vm->kvm_fd, KVM_GET_MSRS, msrs);
+}
+
 /*
  * VM Create
  *
diff --git a/tools/testing/selftests/kvm/x86_64/state_test.c b/tools/testing/selftests/kvm/x86_64/state_test.c
index f6c8b9042f8a..2d61dc5c2dcc 100644
--- a/tools/testing/selftests/kvm/x86_64/state_test.c
+++ b/tools/testing/selftests/kvm/x86_64/state_test.c
@@ -152,6 +152,61 @@ static void __attribute__((__flatten__)) guest_code(void *arg)
 	GUEST_DONE();
 }
 
+#define  KVM_MSR_FEATURE_N  64
+
+static int test_kvm_get_feature_msr_one(struct kvm_vm *vm, __u32 index,
+					struct kvm_msrs *msrs)
+{
+	msrs->nmsrs = 1;
+	msrs->entries[0].index = index;
+	return _kvm_vm_get_feature_msrs(vm, msrs);
+}
+
+static void test_kvm_get_msr_features(struct kvm_vm *vm)
+{
+	struct kvm_msr_list *msr_list;
+	struct kvm_msrs *msrs;
+	int i, ret, sum;
+
+	if (!kvm_check_cap(KVM_CAP_GET_MSR_FEATURES)) {
+		pr_info("skipping kvm get msr features test\n");
+		return;
+	}
+
+	msr_list = calloc(1, sizeof(struct kvm_msr_list) +
+			  sizeof(__u32) * KVM_MSR_FEATURE_N);
+	msr_list->nmsrs = KVM_MSR_FEATURE_N;
+
+	TEST_ASSERT(msr_list, "msr_list allocation failed\n");
+
+	kvm_vm_get_msr_feature_index_list(vm, msr_list);
+
+	msrs = calloc(1, sizeof(struct kvm_msrs) +
+		      sizeof(struct kvm_msr_entry));
+
+	TEST_ASSERT(msrs, "msr entries allocation failed\n");
+
+	sum = 0;
+	for (i = 0; i < msr_list->nmsrs; i++) {
+		ret = test_kvm_get_feature_msr_one(vm, msr_list->indices[i],
+						    msrs);
+		TEST_ASSERT(ret >= 0, "KVM_GET_MSR failed: %d\n", ret);
+		sum += ret;
+	}
+	TEST_ASSERT(sum > 0, "KVM_GET_MSR has no feature msr\n");
+
+	/*
+	 * Test invalid msr.  Note the retcode can be either 0 or 1 depending
+	 * on kvm.ignore_msrs
+	 */
+	ret = test_kvm_get_feature_msr_one(vm, (__u32)-1, msrs);
+	TEST_ASSERT(ret >= 0 && ret <= 1,
+		    "KVM_GET_MSR on invalid msr error: %d\n", ret);
+
+	free(msrs);
+	free(msr_list);
+}
+
 int main(int argc, char *argv[])
 {
 	vm_vaddr_t nested_gva = 0;
@@ -168,6 +223,9 @@ int main(int argc, char *argv[])
 	vcpu_set_cpuid(vm, VCPU_ID, kvm_get_supported_cpuid());
 	run = vcpu_state(vm, VCPU_ID);
 
+	/* Test KVM_GET_MSR for VM */
+	test_kvm_get_msr_features(vm);
+
 	vcpu_regs_get(vm, VCPU_ID, &regs1);
 
 	if (kvm_check_cap(KVM_CAP_NESTED_STATE)) {
-- 
2.26.2