? 2023/2/27 17:18, Longpeng(Mike) ??:> From: Longpeng <longpeng2 at huawei.com>
>
> Support doorbell mapping for vdpasim devices, then we can test the notify
> passthrough feature even if there's no real hardware on hand.
>
> Allocates a dummy page which is used to emulate the notify page of the
device,
> all VQs share the same notify register that initiated to 0xffff. A
periodic
> work will check whether there're requests need to process ( the value
of the
> notify register is 0xffff or not ).
>
> We can test on QEMU with:
> -device vhost-vdpa-device-pci,vhostdev=/dev/vhost-vdpa-0,page-per-vq=on
>
> Signed-off-by: Longpeng <longpeng2 at huawei.com>
Acked-by: Jason Wang <jasowang at redhat.com>
Thanks
> ---
> drivers/vdpa/vdpa_sim/vdpa_sim.c | 67 ++++++++++++++++++++++++++++++++
> drivers/vdpa/vdpa_sim/vdpa_sim.h | 3 ++
> 2 files changed, 70 insertions(+)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c
b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index cb88891b44a8..5a8c820b179f 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -39,6 +39,8 @@ MODULE_PARM_DESC(max_iotlb_entries,
> #define VDPASIM_QUEUE_ALIGN PAGE_SIZE
> #define VDPASIM_QUEUE_MAX 256
> #define VDPASIM_VENDOR_ID 0
> +#define VDPASIM_VRING_POLL_PERIOD 100 /* ms */
> +#define VDPASIM_NOTIFY_DEFVAL 0xffff
>
> static struct vdpasim *vdpa_to_sim(struct vdpa_device *vdpa)
> {
> @@ -245,6 +247,28 @@ static const struct dma_map_ops vdpasim_dma_ops = {
> static const struct vdpa_config_ops vdpasim_config_ops;
> static const struct vdpa_config_ops vdpasim_batch_config_ops;
>
> +static void vdpasim_notify_work(struct work_struct *work)
> +{
> + struct vdpasim *vdpasim;
> + u16 *val;
> +
> + vdpasim = container_of(work, struct vdpasim, notify_work.work);
> +
> + if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK))
> + goto out;
> +
> + if (!vdpasim->running)
> + goto out;
> +
> + val = (u16 *)vdpasim->notify;
> + if (xchg(val, VDPASIM_NOTIFY_DEFVAL) != VDPASIM_NOTIFY_DEFVAL)
> + schedule_work(&vdpasim->work);
> +
> +out:
> + schedule_delayed_work(&vdpasim->notify_work,
> + msecs_to_jiffies(VDPASIM_VRING_POLL_PERIOD));
> +}
> +
> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
> const struct vdpa_dev_set_config *config)
> {
> @@ -286,6 +310,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr
*dev_attr,
> set_dma_ops(dev, &vdpasim_dma_ops);
> vdpasim->vdpa.mdev = dev_attr->mgmt_dev;
>
> + INIT_DELAYED_WORK(&vdpasim->notify_work, vdpasim_notify_work);
> +
> + vdpasim->notify = (u16 *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
> + if (!vdpasim->notify)
> + goto err_iommu;
> + WRITE_ONCE(*vdpasim->notify, VDPASIM_NOTIFY_DEFVAL);
> +
> vdpasim->config = kzalloc(dev_attr->config_size, GFP_KERNEL);
> if (!vdpasim->config)
> goto err_iommu;
> @@ -320,6 +351,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr
*dev_attr,
>
> vdpasim->vdpa.dma_dev = dev;
>
> + /*
> + * Start periodic (every 100ms) notify work, it won't introduce
> + * any overhead if the device is not started.
> + */
> + schedule_delayed_work(&vdpasim->notify_work,
> + msecs_to_jiffies(VDPASIM_VRING_POLL_PERIOD));
> +
> return vdpasim;
>
> err_iommu:
> @@ -671,11 +709,34 @@ static int vdpasim_dma_unmap(struct vdpa_device
*vdpa, unsigned int asid,
> return 0;
> }
>
> +static pgprot_t vdpasim_get_vq_notification_pgprot(struct vdpa_device
*vdpa,
> + u16 qid, pgprot_t prot)
> +{
> + /*
> + * We use normal RAM pages to emulate the vq notification area, so
> + * just keep the pgprot as it mmaped.
> + */
> + return prot;
> +}
> +
> +static struct vdpa_notification_area
> +vdpasim_get_vq_notification(struct vdpa_device *vdpa, u16 qid)
> +{
> + struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> + struct vdpa_notification_area notify;
> +
> + notify.addr = virt_to_phys((void *)vdpasim->notify);
> + notify.size = PAGE_SIZE;
> +
> + return notify;
> +}
> +
> static void vdpasim_free(struct vdpa_device *vdpa)
> {
> struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
> int i;
>
> + cancel_delayed_work_sync(&vdpasim->notify_work);
> cancel_work_sync(&vdpasim->work);
>
> for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
> @@ -694,6 +755,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
> kfree(vdpasim->iommu);
> kfree(vdpasim->vqs);
> kfree(vdpasim->config);
> + if (vdpasim->notify)
> + free_page((unsigned long)vdpasim->notify);
> }
>
> static const struct vdpa_config_ops vdpasim_config_ops = {
> @@ -705,6 +768,8 @@ static const struct vdpa_config_ops vdpasim_config_ops
= {
> .get_vq_ready = vdpasim_get_vq_ready,
> .set_vq_state = vdpasim_set_vq_state,
> .get_vq_state = vdpasim_get_vq_state,
> + .get_vq_notification = vdpasim_get_vq_notification,
> + .get_vq_notification_pgprot = vdpasim_get_vq_notification_pgprot,
> .get_vq_align = vdpasim_get_vq_align,
> .get_vq_group = vdpasim_get_vq_group,
> .get_device_features = vdpasim_get_device_features,
> @@ -738,6 +803,8 @@ static const struct vdpa_config_ops
vdpasim_batch_config_ops = {
> .get_vq_ready = vdpasim_get_vq_ready,
> .set_vq_state = vdpasim_set_vq_state,
> .get_vq_state = vdpasim_get_vq_state,
> + .get_vq_notification = vdpasim_get_vq_notification,
> + .get_vq_notification_pgprot = vdpasim_get_vq_notification_pgprot,
> .get_vq_align = vdpasim_get_vq_align,
> .get_vq_group = vdpasim_get_vq_group,
> .get_device_features = vdpasim_get_device_features,
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h
b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index 0e78737dcc16..786e902de0b2 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -69,6 +69,9 @@ struct vdpasim {
> bool running;
> /* spinlock to synchronize iommu table */
> spinlock_t iommu_lock;
> + /* dummy notify page */
> + u16 *notify;
> + struct delayed_work notify_work;
> };
>
> struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *attr,