On Thu, Sep 21, 2023 at 10:07 PM Cindy Lu <lulu@xxxxxxxxxx> wrote:
On Mon, Sep 18, 2023 at 4:49 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
The process for this reconnecttion is
On Tue, Sep 12, 2023 at 11:01 AM Cindy Lu <lulu@xxxxxxxxxx> 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.
Signed-off-by: Cindy Lu <lulu@xxxxxxxxxx>
---
drivers/vdpa/vdpa_user/vduse_dev.c | 15 +++++++++++++++
include/uapi/linux/vduse.h | 15 +++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c
index 680b23dbdde2..c99f99892b5c 100644
--- a/drivers/vdpa/vdpa_user/vduse_dev.c
+++ b/drivers/vdpa/vdpa_user/vduse_dev.c
@@ -1368,6 +1368,21 @@ 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;
+
+ 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 d585425803fd..ce55e34f63d7 100644
--- a/include/uapi/linux/vduse.h
+++ b/include/uapi/linux/vduse.h
@@ -356,4 +356,19 @@ struct vhost_reconnect_vring {
_Bool avail_wrap_counter;
};
+/**
+ * struct vduse_reconnect_mmap_info
+ * @size: mapping memory size, always page_size here
+ * @max_index: the number of pages allocated in kernel,just
+ * use for check
+ */
+
+struct vduse_reconnect_mmap_info {
+ __u32 size;
+ __u32 max_index;
+};
One thing I didn't understand is that, aren't the things we used to
store connection info belong to uAPI? If not, how can we make sure the
connections work across different vendors/implementations. If yes,
where?
Thanks
A.The first-time connection
1> The userland app checks if the device exists
2> use the ioctl to create the vduse device
3> Mapping the kernel page to userland and save the
App-version/features/other information to this page
4> if the Userland app needs to exit, then the Userland app will only
unmap the page and then exit
B, the re-connection
1> the userland app finds the device is existing
2> Mapping the kernel page to userland
3> check if the information in shared memory is satisfied to
reconnect,if ok then continue to reconnect
4> continue working
For now these information are all from userland,So here the page will
be maintained by the userland App
in the previous code we only saved the api-version by uAPI . if we
need to support reconnection maybe we need to add 2 new uAPI for this,
one of the uAPI is to save the reconnect information and another is
to get the information
maybe something like
struct vhost_reconnect_data {
uint32_t version;
uint64_t features;
uint8_t status;
struct virtio_net_config config;
uint32_t nr_vrings;
};
Probably, then we can make sure the re-connection works across
different vduse-daemon implementations.
#define VDUSE_GET_RECONNECT_INFO _IOR (VDUSE_BASE, 0x1c, struct
vhost_reconnect_data)
#define VDUSE_SET_RECONNECT_INFO _IOWR(VDUSE_BASE, 0x1d, struct
vhost_reconnect_data)
Not sure I get this, but the idea is to map those pages to user space,
any reason we need this uAPI?
Thanks
Thanks
Cindy
+
+#define VDUSE_GET_RECONNECT_INFO \
+ _IOWR(VDUSE_BASE, 0x1b, struct vduse_reconnect_mmap_info)
+
#endif /* _UAPI_VDUSE_H_ */
--
2.34.3