uio_hv_generic: create send and receive buffers

Map in receive and send buffers for networking in UIO device.
These buffers are special and need to be setup by kernel
API's; userspace can not do it.
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/driver-api/uio-howto.rst

@@ -702,6 +702,8 @@ The vmbus device regions are mapped into uio device resources:
     0) Channel ring buffers: guest to host and host to guest
     1) Guest to host interrupt signalling pages
     2) Guest to host monitor page
+    3) Network receive buffer region
+    4) Network send buffer region
 
 Further information
 ===================

drivers/uio/uio_hv_generic.c

@@ -39,6 +39,10 @@
 #define DRIVER_AUTHOR	"Stephen Hemminger <sthemmin at microsoft.com>"
 #define DRIVER_DESC	"Generic UIO driver for VMBus devices"
 
+#define HV_RING_SIZE	 512	/* pages */
+#define SEND_BUFFER_SIZE (15 * 1024 * 1024)
+#define RECV_BUFFER_SIZE (15 * 1024 * 1024)
+
 /*
  * List of resources to be mapped to user space
  * can be extended up to MAX_UIO_MAPS(5) items
@@ -47,13 +51,21 @@ enum hv_uio_map {
 	TXRX_RING_MAP = 0,
 	INT_PAGE_MAP,
 	MON_PAGE_MAP,
+	RECV_BUF_MAP,
+	SEND_BUF_MAP
 };
 
-#define HV_RING_SIZE	512
-
 struct hv_uio_private_data {
 	struct uio_info info;
 	struct hv_device *device;
+
+	void	*recv_buf;
+	u32	recv_gpadl;
+	char	recv_name[32];	/* "recv_4294967295" */
+
+	void	*send_buf;
+	u32	send_gpadl;
+	char	send_name[32];
 };
 
 /*
@@ -91,6 +103,19 @@ static void hv_uio_channel_cb(void *context)
 	uio_event_notify(&pdata->info);
 }
 
+
+static void
+hv_uio_cleanup(struct hv_device *dev, struct hv_uio_private_data *pdata)
+{
+	if (pdata->send_gpadl)
+		vmbus_teardown_gpadl(dev->channel, pdata->send_gpadl);
+	vfree(pdata->send_buf);
+
+	if (pdata->recv_gpadl)
+		vmbus_teardown_gpadl(dev->channel, pdata->recv_gpadl);
+	vfree(pdata->recv_buf);
+}
+
 static int
 hv_uio_probe(struct hv_device *dev,
 	     const struct hv_vmbus_device_id *dev_id)
@@ -137,6 +162,46 @@ hv_uio_probe(struct hv_device *dev,
 	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
 	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 
+	pdata->recv_buf = vzalloc(RECV_BUFFER_SIZE);
+	if (pdata->recv_buf == NULL) {
+		ret = -ENOMEM;
+		goto fail_close;
+	}
+
+	ret = vmbus_establish_gpadl(dev->channel, pdata->recv_buf,
+				    RECV_BUFFER_SIZE, &pdata->recv_gpadl);
+	if (ret)
+		goto fail_close;
+
+	/* put Global Physical Address Label in name */
+	snprintf(pdata->recv_name, sizeof(pdata->recv_name),
+		 "recv:%u", pdata->recv_gpadl);
+	pdata->info.mem[RECV_BUF_MAP].name = pdata->recv_name;
+	pdata->info.mem[RECV_BUF_MAP].addr
+		= (phys_addr_t)pdata->recv_buf;
+	pdata->info.mem[RECV_BUF_MAP].size = RECV_BUFFER_SIZE;
+	pdata->info.mem[RECV_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
+
+
+	pdata->send_buf = vzalloc(SEND_BUFFER_SIZE);
+	if (pdata->send_buf == NULL) {
+		ret = -ENOMEM;
+		goto fail_close;
+	}
+
+	ret = vmbus_establish_gpadl(dev->channel, pdata->send_buf,
+				    SEND_BUFFER_SIZE, &pdata->send_gpadl);
+	if (ret)
+		goto fail_close;
+
+	snprintf(pdata->send_name, sizeof(pdata->send_name),
+		 "send:%u", pdata->send_gpadl);
+	pdata->info.mem[SEND_BUF_MAP].name = pdata->send_name;
+	pdata->info.mem[SEND_BUF_MAP].addr
+		= (phys_addr_t)pdata->send_buf;
+	pdata->info.mem[SEND_BUF_MAP].size = SEND_BUFFER_SIZE;
+	pdata->info.mem[SEND_BUF_MAP].memtype = UIO_MEM_VIRTUAL;
+
 	pdata->info.priv = pdata;
 	pdata->device = dev;
 
@@ -151,6 +216,7 @@ hv_uio_probe(struct hv_device *dev,
 	return 0;
 
 fail_close:
+	hv_uio_cleanup(dev, pdata);
 	vmbus_close(dev->channel);
 fail:
 	kfree(pdata);
@@ -167,6 +233,7 @@ hv_uio_remove(struct hv_device *dev)
 		return 0;
 
 	uio_unregister_device(&pdata->info);
+	hv_uio_cleanup(dev, pdata);
 	hv_set_drvdata(dev, NULL);
 	vmbus_close(dev->channel);
 	kfree(pdata);