Re: [Qemu-devel] [PATCH v3] crypto: add virtio-crypto driver

[Cornelia Huck]

On Mon, 28 Nov 2016 20:08:23 +0800
Gonglei <address@hidden> wrote:

> +static int virtcrypto_update_status(struct virtio_crypto *vcrypto)
> +{
> +     u32 status;
> +     int err;
> +
> +     virtio_cread(vcrypto->vdev,
> +         struct virtio_crypto_config, status, &status);
> +
> +     /* Ignore unknown (future) status bits */
> +     status &= VIRTIO_CRYPTO_S_HW_READY;

I'm wondering what the driver really should do if it encounters unknown
status bits.

I'd expect that new status bits are guarded by a feature bit and that
the device should not set status bits if the respective feature bit has
not been negotiated. Therefore, unknown status bits would be a host
error and the driver should consider the device to be broken.

Thoughts?

> +
> +     if (vcrypto->status == status)
> +             return 0;
> +
> +     vcrypto->status = status;
> +
> +     if (vcrypto->status & VIRTIO_CRYPTO_S_HW_READY) {
> +             err = virtcrypto_dev_start(vcrypto);
> +             if (err) {
> +                     dev_err(&vcrypto->vdev->dev,
> +                             "Failed to start virtio crypto device.\n");
> +                     virtcrypto_dev_stop(vcrypto);
> +                     return -EPERM;
> +             }
> +             dev_info(&vcrypto->vdev->dev, "Accelerator is ready\n");
> +     } else {
> +             virtcrypto_dev_stop(vcrypto);
> +             dev_info(&vcrypto->vdev->dev, "Accelerator is not ready\n");
> +     }
> +
> +     return 0;
> +}
> +