Re: [RFC v2 1/2] virtio: add pmem driver

From: Michael S. Tsirkin
Date: Wed Apr 25 2018 - 10:53:14 EST


On Wed, Apr 25, 2018 at 04:54:13PM +0530, Pankaj Gupta wrote:
> diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
> index 6d5c3b2..5ebd049 100644
> --- a/include/uapi/linux/virtio_ids.h
> +++ b/include/uapi/linux/virtio_ids.h
> @@ -43,5 +43,6 @@
> #define VIRTIO_ID_INPUT 18 /* virtio input */
> #define VIRTIO_ID_VSOCK 19 /* virtio vsock transport */
> #define VIRTIO_ID_CRYPTO 20 /* virtio crypto */
> +#define VIRTIO_ID_PMEM 21 /* virtio pmem */
>
> #endif /* _LINUX_VIRTIO_IDS_H */

Please register the device id with virtio TC.


> diff --git a/include/uapi/linux/virtio_pmem.h b/include/uapi/linux/virtio_pmem.h
> new file mode 100644
> index 0000000..2ec27cb
> --- /dev/null
> +++ b/include/uapi/linux/virtio_pmem.h
> @@ -0,0 +1,58 @@
> +/* Virtio pmem Driver
> + *
> + * Discovers persitent memory range information
> + * from host and provides a virtio based flushing
> + * interface.
> + */
> +
> +#ifndef _LINUX_VIRTIO_PMEM_H
> +#define _LINUX_VIRTIO_PMEM_H
> +
> +#include <linux/types.h>
> +#include <linux/virtio_types.h>
> +#include <linux/virtio_ids.h>
> +#include <linux/virtio_config.h>
> +#include <linux/virtio_ring.h>
> +
> +
> +struct virtio_pmem_config {
> +

don't add empty lines pls.

> + uint64_t start;
> + uint64_t size;

Used LE fields for everything.

> +};
> +
> +struct virtio_pmem {
> +
> + struct virtio_device *vdev;
> + struct virtqueue *req_vq;
> +
> + uint64_t start;
> + uint64_t size;
> +} __packed;

This does not belong in uapi, and should not be packed either.

> +
> +static struct virtio_device_id id_table[] = {
> + { VIRTIO_ID_PMEM, VIRTIO_DEV_ANY_ID },
> + { 0 },
> +};
> +
> +void virtio_pmem_flush(struct device *dev)
> +{
> + struct scatterlist sg;
> + struct virtio_device *vdev = dev_to_virtio(dev->parent->parent);
> + struct virtio_pmem *vpmem = vdev->priv;
> + char *buf = "FLUSH";
> + int err;
> +
> + sg_init_one(&sg, buf, sizeof(buf));
> +
> + err = virtqueue_add_outbuf(vpmem->req_vq, &sg, 1, buf, GFP_KERNEL);
> +
> + if (err) {
> + dev_err(&vdev->dev, "failed to send command to virtio pmem device\n");
> + return;
> + }
> +
> + virtqueue_kick(vpmem->req_vq);
> +};

this doesn't belong in uapi.

> +
> +#endif
> --
> 2.9.3