[PATCH] hyper-v: allow access to vmbus from userspace driver

[Stephen Hemminger <stephen@networkplumber.org>]

Brocade is submitting a hyper-v driver for DPDK <dev@dpdk.org>
but this driver needs a hook in the hyper-v bus layer
to allow the additional hv_uio driver to access the shared vmbus
pages. The hv_uio driver lives in DPDK (like igb_uio) and provides
userspace access to raw network packets.

Signed-off-by: Stas Egorov <segorov@mirantis.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

---
 drivers/hv/connection.c |   20 +++++++++++++++++---
 include/linux/hyperv.h  |    3 +++
 2 files changed, 20 insertions(+), 3 deletions(-)

--- a/drivers/hv/connection.c	2015-02-03 10:58:51.751752450 -0800
+++ b/drivers/hv/connection.c	2015-02-03 10:58:51.751752450 -0800
@@ -64,6 +64,21 @@ static __u32 vmbus_get_next_version(__u3
 	}
 }
 
+static const uuid_le HV_NET_GUID = {
+	.b = {
+		0x63, 0x51, 0x61, 0xf8, 0x3e, 0xdf, 0xc5, 0x46,
+		0x91, 0x3f, 0xf2, 0xd2, 0xf9, 0x65, 0xed, 0x0e
+	}
+};
+
+void vmbus_get_pages(unsigned long *int_page, unsigned long monitor_pages[2])
+{
+	*int_page = (unsigned long)vmbus_connection.int_page;
+	monitor_pages[0] = (unsigned long)vmbus_connection.monitor_pages[0];
+	monitor_pages[1] = (unsigned long)vmbus_connection.monitor_pages[1];
+}
+EXPORT_SYMBOL_GPL(vmbus_get_pages);
+
 static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
 					__u32 version)
 {
@@ -347,7 +362,8 @@ static void process_chn_event(u32 relid)
 			else
 				bytes_to_read = 0;
 		} while (read_state && (bytes_to_read != 0));
-	} else {
+	} else if (!memcmp(&channel->device_obj->dev_type, &HV_NET_GUID,
+			   sizeof(uuid_le))) {
 		pr_err("no channel callback for relid - %u\n", relid);
 	}
 
--- a/include/linux/hyperv.h	2015-02-03 10:58:51.751752450 -0800
+++ b/include/linux/hyperv.h	2015-02-03 10:58:51.751752450 -0800
@@ -868,6 +868,9 @@ extern int vmbus_recvpacket_raw(struct v
 
 extern void vmbus_ontimer(unsigned long data);
 
+extern void vmbus_get_pages(unsigned long *int_page,
+			    unsigned long monitor_pages[2]);
+
 /* Base driver object */
 struct hv_driver {
 	const char *name;