Re: [PATCH 1/2] KVM: selftests: Add get featured msrs test case

[Vitaly Kuznetsov]

Peter Xu <peterx@xxxxxxxxxx> writes:

> 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 [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@xxxxxxxxxx>
> ---
>  .../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..e34cf263b20a 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..3c16fa044335 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);
> +}

I *think* that the non-written rule for kvm selftests is that functions
without '_' prefix check ioctl return value with TEST_ASSERT() and
functions with it don't (e.g. _vcpu_run()/vcpu_run()) but maybe it's
just me.

> +
>  /*
>   * 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..7ce9920e526a 100644
> --- a/tools/testing/selftests/kvm/x86_64/state_test.c
> +++ b/tools/testing/selftests/kvm/x86_64/state_test.c

I would not overload state_test with this new check and create a new
one. The benefit is that when one of these tests fail we still get the
result of the other one so it's not 'everything works' vs 'everything is
broken' type of log.

> @@ -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)) {

-- 
Vitaly