Messages in this thread | | | From | Jason Wang <> | Date | Wed, 22 Nov 2023 14:28:53 +0800 | Subject | Re: [PATCH v2 3/5] vduse: Add new ioctl VDUSE_GET_RECONNECT_INFO |
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On Tue, Nov 21, 2023 at 3:31 PM Cindy Lu <lulu@redhat.com> wrote: > > In VDUSE_GET_RECONNECT_INFO, the Userspace App can get the map size > and The number of mapping memory pages from the kernel. The userspace > App can use this information to map the pages. > > Add struct vhost_reconnect_data/vhost_reconnect_vring for sync the > information in reconnection > > Signed-off-by: Cindy Lu <lulu@redhat.com> > --- > drivers/vdpa/vdpa_user/vduse_dev.c | 15 +++++++++ > include/uapi/linux/vduse.h | 50 ++++++++++++++++++++++++++++++ > 2 files changed, 65 insertions(+) > > diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c > index ccb30e98bab5..d0fe9a7e86ab 100644 > --- a/drivers/vdpa/vdpa_user/vduse_dev.c > +++ b/drivers/vdpa/vdpa_user/vduse_dev.c > @@ -1343,6 +1343,21 @@ static long vduse_dev_ioctl(struct file *file, unsigned int cmd, > ret = 0; > break; > } > + case VDUSE_GET_RECONNECT_INFO: { > + struct vduse_reconnect_mmap_info info; > + > + ret = -EFAULT; > + if (copy_from_user(&info, argp, sizeof(info))) > + break; > + > + info.size = PAGE_SIZE; > + info.max_index = dev->vq_num + 1;
It looks to be both PAGE_SIZE and vq_num is the well knowledge that doesn't require a query?
> + > + if (copy_to_user(argp, &info, sizeof(info))) > + break; > + ret = 0; > + break; > + } > default: > ret = -ENOIOCTLCMD; > break; > diff --git a/include/uapi/linux/vduse.h b/include/uapi/linux/vduse.h > index 11bd48c72c6c..c0b7133aebfd 100644 > --- a/include/uapi/linux/vduse.h > +++ b/include/uapi/linux/vduse.h > @@ -3,6 +3,7 @@ > #define _UAPI_VDUSE_H_ > > #include <linux/types.h> > +#include <linux/virtio_net.h> > > #define VDUSE_BASE 0x81 > > @@ -350,4 +351,53 @@ struct vduse_dev_response { > }; > }; > > +/** > + * struct vhost_reconnect_data - saved the reconnect info for device > + * @version; version for userspace APP > + * @reconnected: indetify if this is reconnected. userspace APP needs set this bit to 1 > + * while reconnecting.kernel will use this bit to indetify if this is > + * reconnect
Typos.
> + * @features; Device features negotiated in the last connect. > + * @status; Device status in last reconnect > + * @nr_vrings; number of active vqs in last connect
What's the meaning of "active vqs"? Is it the #active_queue_pairs? If yes, couldn't we get it from the virtio_net_config?
> + * @struct virtio_net_config config; the config in last connect > + */ > + > +struct vhost_reconnect_data { > + __u32 version; > + __u32 reconnected; > + __u64 features; > + __u8 status; > + __u32 nr_vrings; > + struct virtio_net_config config;
This seems like a layer violation. The fields here needs to be type agnostic or we should introduce a new device specific area with a union.
Or can we simply invent VDUSE_DEV_GET_CONFIG() to do this?
> +}; > + > +/** > + * struct vhost_reconnect_vring -saved the reconnect info for vqs > + * when use split mode will only use last_avail_idx > + * when use packed mode will use both last_avail_idx and avail_wrap_counter
How about last_used_idx and last_used_wrap_counter.
Btw, vDPA or vhost-vDPA has a good uAPI for this, can we reuse that?
Thanks
> + * userspace App > + * @last_avail_idx: device last available index > + * @avail_wrap_counter: Driver ring wrap counter > + */ > +struct vhost_reconnect_vring { > + __u16 last_avail_idx; > + __u16 avail_wrap_counter; > +}; > + > +/** > + * struct vduse_reconnect_mmap_info > + * @size: mapping memory size, here we use page_size > + * @max_index: the number of pages allocated in kernel,just > + * use for sanity check > + */ > + > +struct vduse_reconnect_mmap_info { > + __u32 size; > + __u32 max_index; > +}; > + > +#define VDUSE_GET_RECONNECT_INFO \ > + _IOWR(VDUSE_BASE, 0x1b, struct vduse_reconnect_mmap_info) > + > #endif /* _UAPI_VDUSE_H_ */ > -- > 2.34.3 >
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