2024-05-17 14:59:15

by Xuewei Niu

[permalink] [raw]
Subject: [RFC PATCH 5/5] vsock: Add an ioctl request to get all CIDs

The new request is called `IOCTL_VM_SOCKETS_GET_LOCAL_CIDS`. And the old
one, `IOCTL_VM_SOCKETS_GET_LOCAL_CID` is retained.

For the transport that supports multi-devices:

* `IOCTL_VM_SOCKETS_GET_LOCAL_CID` returns "-1";
* `IOCTL_VM_SOCKETS_GET_LOCAL_CIDS` returns a vector of CIDS. The usage is
shown as following.

```
struct vsock_local_cids local_cids;
if ((ret = ioctl(fd, IOCTL_VM_SOCKETS_GET_LOCAL_CIDS, &local_cids))) {
perror("failed to get cids");
exit(1);
}
for (i = 0; i<local_cids.nr; i++) {
if (i == (local_cids.nr - 1))
printf("%u", local_cids.data[i]);
else
printf("%u,", local_cids.data[i]);
}
```

Signed-off-by: Xuewei Niu <[email protected]>
---
include/net/af_vsock.h | 7 +++++++
include/uapi/linux/vm_sockets.h | 8 ++++++++
net/vmw_vsock/af_vsock.c | 19 +++++++++++++++++++
3 files changed, 34 insertions(+)

diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
index 25f7dc3d602d..2febc816e388 100644
--- a/include/net/af_vsock.h
+++ b/include/net/af_vsock.h
@@ -264,4 +264,11 @@ static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
{
return t->msgzerocopy_allow && t->msgzerocopy_allow();
}
+
+/**** IOCTL ****/
+/* Type of return value of IOCTL_VM_SOCKETS_GET_LOCAL_CIDS. */
+struct vsock_local_cids {
+ int nr;
+ unsigned int data[MAX_VSOCK_NUM];
+};
#endif /* __AF_VSOCK_H__ */
diff --git a/include/uapi/linux/vm_sockets.h b/include/uapi/linux/vm_sockets.h
index 36ca5023293a..01f73fb7af5a 100644
--- a/include/uapi/linux/vm_sockets.h
+++ b/include/uapi/linux/vm_sockets.h
@@ -195,8 +195,16 @@ struct sockaddr_vm {

#define MAX_VSOCK_NUM 16

+/* Return actual context id if the transport not support vsock
+ * multi-devices. Otherwise, return `-1U`.
+ */
+
#define IOCTL_VM_SOCKETS_GET_LOCAL_CID _IO(7, 0xb9)

+/* Only available in transports that support multiple devices. */
+
+#define IOCTL_VM_SOCKETS_GET_LOCAL_CIDS _IOR(7, 0xba, struct vsock_local_cids)
+
/* MSG_ZEROCOPY notifications are encoded in the standard error format,
* sock_extended_err. See Documentation/networking/msg_zerocopy.rst in
* kernel source tree for more details.
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index 3b34be802bf2..2ea2ff52f15b 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -2454,6 +2454,7 @@ static long vsock_dev_do_ioctl(struct file *filp,
u32 __user *p = ptr;
u32 cid = VMADDR_CID_ANY;
int retval = 0;
+ struct vsock_local_cids local_cids;

switch (cmd) {
case IOCTL_VM_SOCKETS_GET_LOCAL_CID:
@@ -2469,6 +2470,24 @@ static long vsock_dev_do_ioctl(struct file *filp,
retval = -EFAULT;
break;

+ case IOCTL_VM_SOCKETS_GET_LOCAL_CIDS:
+ if (!transport_g2h || !transport_g2h->get_local_cids)
+ goto fault;
+
+ rcu_read_lock();
+ local_cids.nr = transport_g2h->get_local_cids(local_cids.data);
+ rcu_read_unlock();
+
+ if (local_cids.nr < 0 ||
+ copy_to_user(p, &local_cids, sizeof(local_cids)))
+ goto fault;
+
+ break;
+
+fault:
+ retval = -EFAULT;
+ break;
+
default:
retval = -ENOIOCTLCMD;
}
--
2.34.1



2024-05-23 10:46:16

by Stefano Garzarella

[permalink] [raw]
Subject: Re: [RFC PATCH 5/5] vsock: Add an ioctl request to get all CIDs

On Fri, May 17, 2024 at 10:46:07PM GMT, Xuewei Niu wrote:
>The new request is called `IOCTL_VM_SOCKETS_GET_LOCAL_CIDS`. And the old
>one, `IOCTL_VM_SOCKETS_GET_LOCAL_CID` is retained.
>
>For the transport that supports multi-devices:
>
>* `IOCTL_VM_SOCKETS_GET_LOCAL_CID` returns "-1";

What about returning the default CID (lower prio)?

>* `IOCTL_VM_SOCKETS_GET_LOCAL_CIDS` returns a vector of CIDS. The usage
>is
>shown as following.
>
>```
>struct vsock_local_cids local_cids;
>if ((ret = ioctl(fd, IOCTL_VM_SOCKETS_GET_LOCAL_CIDS, &local_cids))) {
> perror("failed to get cids");
> exit(1);
>}
>for (i = 0; i<local_cids.nr; i++) {
> if (i == (local_cids.nr - 1))
> printf("%u", local_cids.data[i]);
> else
> printf("%u,", local_cids.data[i]);
>}
>```
>
>Signed-off-by: Xuewei Niu <[email protected]>
>---
> include/net/af_vsock.h | 7 +++++++
> include/uapi/linux/vm_sockets.h | 8 ++++++++
> net/vmw_vsock/af_vsock.c | 19 +++++++++++++++++++
> 3 files changed, 34 insertions(+)
>
>diff --git a/include/net/af_vsock.h b/include/net/af_vsock.h
>index 25f7dc3d602d..2febc816e388 100644
>--- a/include/net/af_vsock.h
>+++ b/include/net/af_vsock.h
>@@ -264,4 +264,11 @@ static inline bool vsock_msgzerocopy_allow(const struct vsock_transport *t)
> {
> return t->msgzerocopy_allow && t->msgzerocopy_allow();
> }
>+
>+/**** IOCTL ****/
>+/* Type of return value of IOCTL_VM_SOCKETS_GET_LOCAL_CIDS. */
>+struct vsock_local_cids {
>+ int nr;
>+ unsigned int data[MAX_VSOCK_NUM];
>+};
> #endif /* __AF_VSOCK_H__ */
>diff --git a/include/uapi/linux/vm_sockets.h b/include/uapi/linux/vm_sockets.h
>index 36ca5023293a..01f73fb7af5a 100644
>--- a/include/uapi/linux/vm_sockets.h
>+++ b/include/uapi/linux/vm_sockets.h
>@@ -195,8 +195,16 @@ struct sockaddr_vm {
>
> #define MAX_VSOCK_NUM 16

Okay, now I see why you need this in the UAPI, but pleace try to follow
other defines.

What about VM_SOCKETS_MAX_DEVS ?

>
>+/* Return actual context id if the transport not support vsock
>+ * multi-devices. Otherwise, return `-1U`.
>+ */
>+
> #define IOCTL_VM_SOCKETS_GET_LOCAL_CID _IO(7, 0xb9)
>
>+/* Only available in transports that support multiple devices. */
>+
>+#define IOCTL_VM_SOCKETS_GET_LOCAL_CIDS _IOR(7, 0xba, struct vsock_local_cids)
>+
> /* MSG_ZEROCOPY notifications are encoded in the standard error format,
> * sock_extended_err. See Documentation/networking/msg_zerocopy.rst in
> * kernel source tree for more details.
>diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
>index 3b34be802bf2..2ea2ff52f15b 100644
>--- a/net/vmw_vsock/af_vsock.c
>+++ b/net/vmw_vsock/af_vsock.c
>@@ -2454,6 +2454,7 @@ static long vsock_dev_do_ioctl(struct file *filp,
> u32 __user *p = ptr;
> u32 cid = VMADDR_CID_ANY;
> int retval = 0;
>+ struct vsock_local_cids local_cids;
>
> switch (cmd) {
> case IOCTL_VM_SOCKETS_GET_LOCAL_CID:
>@@ -2469,6 +2470,24 @@ static long vsock_dev_do_ioctl(struct file *filp,
> retval = -EFAULT;
> break;
>
>+ case IOCTL_VM_SOCKETS_GET_LOCAL_CIDS:
>+ if (!transport_g2h || !transport_g2h->get_local_cids)
>+ goto fault;
>+
>+ rcu_read_lock();
>+ local_cids.nr = transport_g2h->get_local_cids(local_cids.data);
>+ rcu_read_unlock();
>+
>+ if (local_cids.nr < 0 ||
>+ copy_to_user(p, &local_cids, sizeof(local_cids)))
>+ goto fault;
>+
>+ break;
>+
>+fault:
>+ retval = -EFAULT;
>+ break;
>+
> default:
> retval = -ENOIOCTLCMD;
> }
>--
>2.34.1
>