* Re: [dpdk-dev] [RFC] vhost: support raising device error
2020-10-26 7:25 [dpdk-dev] [RFC] vhost: support raising device error Xueming Li
@ 2021-01-05 9:32 ` Maxime Coquelin
0 siblings, 0 replies; 2+ messages in thread
From: Maxime Coquelin @ 2021-01-05 9:32 UTC (permalink / raw)
To: Xueming Li, Chenbo Xia; +Cc: dev, Matan Azrad, Asaf Penso
Hi Xueming,
On 10/26/20 8:25 AM, Xueming Li wrote:
> According to virtio spec, The device SHOULD set DEVICE_NEEDS_RESET when
> it enters an error state that a reset is needed. If DRIVER_OK is set,
> after it sets DEVICE_NEEDS_RESET, the device MUST send a device
> configuration change notification to the driver.
>
> This patch introduces new api to raise vDPA hardware error and escalates
> configuration change to vhost via client message
> VHOST_USER_SLAVE_CONFIG_CHANGE_MSG.
>
> The vhost should check DRIVER_OK and decide whether to notify driver.
>
> Signed-off-by: Xueming Li <xuemingl@nvidia.com>
> ---
> lib/librte_vhost/rte_vdpa_dev.h | 12 ++++++++++++
> lib/librte_vhost/version.map | 1 +
> lib/librte_vhost/vhost_user.c | 14 ++++++++++++++
> 3 files changed, 27 insertions(+)
>
> diff --git a/lib/librte_vhost/rte_vdpa_dev.h b/lib/librte_vhost/rte_vdpa_dev.h
> index a60183f780..87b7397c6f 100644
> --- a/lib/librte_vhost/rte_vdpa_dev.h
> +++ b/lib/librte_vhost/rte_vdpa_dev.h
> @@ -117,6 +117,18 @@ rte_vdpa_unregister_device(struct rte_vdpa_device *dev);
> int
> rte_vhost_host_notifier_ctrl(int vid, uint16_t qid, bool enable);
>
> +/**
> + * Set device hardware error and notify host.
> + *
> + * @param vid
> + * vhost device id
> + * @return
> + * 0 on success, -1 on failure
> + */
> +__rte_experimental
> +int
> +rte_vhost_host_raise_error(int vid);
> +
> /**
> * Synchronize the used ring from mediated ring to guest, log dirty
> * page for each writeable buffer, caller should handle the used
> diff --git a/lib/librte_vhost/version.map b/lib/librte_vhost/version.map
> index 9183d6f2fc..5a4c5dc818 100644
> --- a/lib/librte_vhost/version.map
> +++ b/lib/librte_vhost/version.map
> @@ -76,4 +76,5 @@ EXPERIMENTAL {
> rte_vhost_async_channel_unregister;
> rte_vhost_submit_enqueue_burst;
> rte_vhost_poll_enqueue_completed;
> + rte_vhost_host_raise_error;
> };
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index d20c8c57ad..d8353176f2 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -2992,6 +2992,20 @@ rte_vhost_slave_config_change(int vid, bool need_reply)
> return vhost_user_slave_config_change(dev, need_reply);
> }
>
> +int
> +rte_vhost_host_raise_error(int vid)
> +{
> + struct virtio_net *dev;
> +
> + dev = get_device(vid);
> + if (!dev)
> + return -ENODEV;
> +
> + dev->status |= VIRTIO_DEVICE_STATUS_DEV_NEED_RESET;
> +
> + return vhost_user_slave_config_change(dev, 0);
In order to be able to send VHOST_USER_SLAVE_CONFIG_CHANGE_MSG request,
we need to negotiate the VHOST_USER_PROTOCOL_F_CONFIG feature, and
ensure it is supported by the master. From the Vhost-user spec in Qemu:
"
``VHOST_USER_SLAVE_CONFIG_CHANGE_MSG``
:id: 2
:equivalent ioctl: N/A
:slave payload: N/A
:master payload: N/A
When ``VHOST_USER_PROTOCOL_F_CONFIG`` is negotiated, vhost-user
slave sends such messages to notify that the virtio device's
configuration space has changed, for those host devices which can
support such feature, host driver can send ``VHOST_USER_GET_CONFIG``
message to slave to get the latest content. If
``VHOST_USER_PROTOCOL_F_REPLY_ACK`` is negotiated, and slave set the
``VHOST_USER_NEED_REPLY`` flag, master must respond with zero when
operation is successfully completed, or non-zero otherwise.
"
Also, it is not clear in the spec that it should be sent on status
updates.
Finally, if we go and advertise we support VHOST_USER_PROTOCOL_F_CONFIG,
we will have to support VHOST_USER_GET_CONFIG and VHOST_USER_SET_CONFIG
request handling in the backend.
I think it might be interesting to support it in the case of vDPA, but
full support needs to be added otherwise it will break.
Thanks,
Maxime
> +}
> +
> static int vhost_user_slave_set_vring_host_notifier(struct virtio_net *dev,
> int index, int fd,
> uint64_t offset,
>
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