On Mon, Nov 11, 2019 at 04:45:07PM +0800, lantianyu1986@gmail.com wrote:

+#define DRIVER_VERSION	"0.0.1"

Never a need for DRIVER_VERSION as your driver just becomes part of the
main kernel tree, so please drop this.  We keep trying to delete these
types of numbers and they keep coming back...

+static void
+vfio_vmbus_new_channel(struct vmbus_channel *new_sc)
+{
+	struct hv_device *hv_dev = new_sc->primary_channel->device_obj;
+	struct device *device = &hv_dev->device;
+	int ret;
+
+	/* Create host communication ring */
+	ret = vmbus_open(new_sc, HV_RING_SIZE, HV_RING_SIZE, NULL, 0,
+			 vfio_vmbus_channel_cb, new_sc);
+	if (ret) {
+		dev_err(device, "vmbus_open subchannel failed: %d\n", ret);
+		return;
+	}
+
+	/* Disable interrupts on sub channel */
+	new_sc->inbound.ring_buffer->interrupt_mask = 1;
+	set_channel_read_mode(new_sc, HV_CALL_ISR);
+
+	ret = sysfs_create_bin_file(&new_sc->kobj, &ring_buffer_bin_attr);

No documentation on this new sysfs file?

And by creating it here, userspace is not notified of it, so tools will
not see it :(

+	if (ret)
+		dev_notice(&hv_dev->device,
+			   "sysfs create ring bin file failed; %d\n", ret);

Doesn't the call spit out an error if something happens?

+	ret = sysfs_create_bin_file(&channel->kobj, &ring_buffer_bin_attr);
+	if (ret)
+		dev_notice(&dev->device,
+			   "sysfs create ring bin file failed; %d\n", ret);
+

Again, don't create sysfs files on your own, the bus code should be
doing this for you automatically and in a way that is race-free.

thanks,

greg k-h