[PATCH] vmbus: get current rte_vmbus_bus struct

[PATCH] vmbus: get current rte_vmbus_bus struct

[Abdelfattah Chehab]

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Hi All,
FOREACH_DEVICE_ON_VMBUS needs rte_vmbus_bus to work on
If static link to libdpdk.a : no issues
If dynamic link to *.so: linker issue, global variable not found.

I suggest this patch to get a current rte_vmbus_bus struct:
Thanks.


diff --git a/dpdk-20.11/drivers/bus/vmbus/rte_bus_vmbus.h b/dpdk-20.11/drivers/bus/vmbus/rte_bus_vmbus.h
--- a/dpdk-20.11/drivers/bus/vmbus/rte_bus_vmbus.h
+++ b/dpdk-20.11/drivers/bus/vmbus/rte_bus_vmbus.h
@@ -414,6 +414,16 @@
               }                                                                                              \
               RTE_PMD_EXPORT_NAME(nm, __COUNTER__)
+/**
+ * Gets the global rte_vmbus_bus struct
+ *
+ * @param bus
+ *          Pointer to rte_vmbus_bus structure.
+ * @return
+ *          Return 0 if success.
+ */
+int rte_vmbus_get_bus(struct rte_vmbus_bus *bus);
+
#ifdef __cplusplus
}
#endif
diff --git a/dpdk-20.11/drivers/bus/vmbus/version.map b/dpdk-20.11/drivers/bus/vmbus/version.map
--- a/dpdk-20.11/drivers/bus/vmbus/version.map
+++ b/dpdk-20.11/drivers/bus/vmbus/version.map
@@ -23,6 +23,7 @@
               rte_vmbus_subchan_open;
               rte_vmbus_unmap_device;
               rte_vmbus_unregister;
+             rte_vmbus_get_bus;
                local: *;
};
diff --git a/dpdk-20.11/drivers/bus/vmbus/vmbus_common.c b/dpdk-20.11/drivers/bus/vmbus/vmbus_common.c
--- a/dpdk-20.11/drivers/bus/vmbus/vmbus_common.c
+++ b/dpdk-20.11/drivers/bus/vmbus/vmbus_common.c
@@ -25,6 +25,17 @@
 extern struct rte_vmbus_bus rte_vmbus_bus;
+/* Gets the global rte_vmbus_bus struct*/
+int rte_vmbus_get_bus(struct rte_vmbus_bus *bus){
+
+  if (!bus)
+    return 1;
+
+  memcpy(bus, &rte_vmbus_bus, sizeof(struct rte_vmbus_bus));
+
+  return 0;
+}
+
/* map a particular resource from a file */
void *
vmbus_map_resource(void *requested_addr, int fd, off_t offset, size_t size,

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Re: [PATCH] vmbus: get current rte_vmbus_bus struct

[David Marchand]

On Wed, Apr 13, 2022 at 9:32 AM Abdelfattah Chehab
<abdelfattah.chehab-ext@ekinops.com> wrote:
>
> Hi All,
>
> FOREACH_DEVICE_ON_VMBUS needs rte_vmbus_bus to work on
>
> If static link to libdpdk.a : no issues
>
> If dynamic link to *.so: linker issue, global variable not found.

Not sure I really get your usecase, but this probably is a linking
issue on your side.


-- 
David Marchand

RE: [PATCH] vmbus: get current rte_vmbus_bus struct

[Abdelfattah Chehab]

The global variable is not accessible from libdpdk.so
I don't really see how the linker can find it in this case.

-----Original Message-----
From: David Marchand <david.marchand@redhat.com> 
Sent: 13 April 2022 10:11
To: Abdelfattah Chehab <abdelfattah.chehab-ext@ekinops.com>
Cc: dev@dpdk.org; stable@dpdk.org
Subject: Re: [PATCH] vmbus: get current rte_vmbus_bus struct

On Wed, Apr 13, 2022 at 9:32 AM Abdelfattah Chehab <abdelfattah.chehab-ext@ekinops.com> wrote:
>
> Hi All,
>
> FOREACH_DEVICE_ON_VMBUS needs rte_vmbus_bus to work on
>
> If static link to libdpdk.a : no issues
>
> If dynamic link to *.so: linker issue, global variable not found.

Not sure I really get your usecase, but this probably is a linking issue on your side.


--
David Marchand

Re: [PATCH] vmbus: get current rte_vmbus_bus struct

[David Marchand]

On Thu, Apr 14, 2022 at 11:58 AM Abdelfattah Chehab
<abdelfattah.chehab-ext@ekinops.com> wrote:
>
> The global variable is not accessible from libdpdk.so
> I don't really see how the linker can find it in this case.

Well, the initial mail was missing a description of the problem.
The patch is badly formatted and sent against 20.11, I did not read it.

The code for iterating over a bus specific object is internal.
We will probably remove this iterator macro from the public API in 22.11.


-- 
David Marchand