Re: [PATCH v2 06/12] selftests: KVM: Add helpers for vCPU device attributes

Andrew Jones
2021-07-21T15:15:07Z

On Fri, Jul 16, 2021 at 09:26:23PM +0000, Oliver Upton wrote:
> vCPU file descriptors are abstracted away from test code in KVM
> selftests, meaning that tests cannot directly access a vCPU's device
> attributes. Add helpers that tests can use to get at vCPU device
> attributes.
>
> Signed-off-by: Oliver Upton <oupton@google.com>
> ---
> .../testing/selftests/kvm/include/kvm_util.h | 9 +++++
> tools/testing/selftests/kvm/lib/kvm_util.c | 38 +++++++++++++++++++
> 2 files changed, 47 insertions(+)
>
> diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
> index a8ac5d52e17b..1b3ef5757819 100644
> --- a/tools/testing/selftests/kvm/include/kvm_util.h
> +++ b/tools/testing/selftests/kvm/include/kvm_util.h
> @@ -240,6 +240,15 @@ int _kvm_device_access(int dev_fd, uint32_t group, uint64_t attr,
> int kvm_device_access(int dev_fd, uint32_t group, uint64_t attr,
> void *val, bool write);
>
> +int _vcpu_has_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr);
> +int vcpu_has_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr);
> +int _vcpu_access_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr, void *val, bool write);
> +int vcpu_access_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr, void *val, bool write);
> +
> const char *exit_reason_str(unsigned int exit_reason);
>
> void virt_pgd_alloc(struct kvm_vm *vm);
> diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
> index 10a8ed691c66..b595e7dc3fc5 100644
> --- a/tools/testing/selftests/kvm/lib/kvm_util.c
> +++ b/tools/testing/selftests/kvm/lib/kvm_util.c
> @@ -2040,6 +2040,44 @@ int kvm_device_access(int dev_fd, uint32_t group, uint64_t attr,
> return ret;
> }
>
> +int _vcpu_has_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr)
> +{
> + struct vcpu *vcpu = vcpu_find(vm, vcpuid);
> +
> + TEST_ASSERT(vcpu, "nonexistent vcpu id: %d", vcpuid);
> +
> + return _kvm_device_check_attr(vcpu->fd, group, attr);
> +}
> +
> +int vcpu_has_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr)
> +{
> + int ret = _vcpu_has_device_attr(vm, vcpuid, group, attr);
> +
> + TEST_ASSERT(!ret, "KVM_HAS_DEVICE_ATTR IOCTL failed, rc: %i errno: %i", ret, errno);
> + return ret;
> +}
> +
> +int _vcpu_access_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr, void *val, bool write)
> +{
> + struct vcpu *vcpu = vcpu_find(vm, vcpuid);
> +
> + TEST_ASSERT(vcpu, "nonexistent vcpu id: %d", vcpuid);
> +
> + return _kvm_device_access(vcpu->fd, group, attr, val, write);
> +}
> +
> +int vcpu_access_device_attr(struct kvm_vm *vm, uint32_t vcpuid, uint32_t group,
> + uint64_t attr, void *val, bool write)
> +{
> + int ret = _vcpu_access_device_attr(vm, vcpuid, group, attr, val, write);
> +
> + TEST_ASSERT(!ret, "KVM_SET|GET_DEVICE_ATTR IOCTL failed, rc: %i errno: %i", ret, errno);
> + return ret;
> +}

Reviewed-by: Andrew Jones <drjones@redhat.com>

The 'assert !ret's are correct here. I see they are not correct in

kvm_device_check_attr
kvm_create_device
kvm_device_access

though, as they are 'assert ret >= 0', but the documentation says 0 on
success. It'd be nice to get that fixed before we build more API on top
of it.

Thanks,
drew

> +
> /*
> * VM Dump
> *
> --
> 2.32.0.402.g57bb445576-goog
>
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