This is a note to let you know that I've just added the patch titled uio_hv_generic: check that host supports monitor page to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: uio_hv_generic-check-that-host-supports-monitor-page.patch and it can be found in the queue-4.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Apr 9 10:16:32 CEST 2018 From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> Date: Tue, 9 Jan 2018 12:57:31 -0800 Subject: uio_hv_generic: check that host supports monitor page From: Stephen Hemminger <stephen@xxxxxxxxxxxxxxxxxx> [ Upstream commit 06028d15177a1b406b7b075ea47c6a352732f23a ] In order for userspace application to signal host, it needs the host to support the monitor page property. Check for the flag and fail if this is not supported. Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/uio/uio_hv_generic.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/drivers/uio/uio_hv_generic.c +++ b/drivers/uio/uio_hv_generic.c @@ -124,6 +124,13 @@ hv_uio_probe(struct hv_device *dev, if (ret) goto fail; + /* Communicating with host has to be via shared memory not hypercall */ + if (!dev->channel->offermsg.monitor_allocated) { + dev_err(&dev->device, "vmbus channel requires hypercall\n"); + ret = -ENOTSUPP; + goto fail_close; + } + dev->channel->inbound.ring_buffer->interrupt_mask = 1; set_channel_read_mode(dev->channel, HV_CALL_DIRECT); Patches currently in stable-queue which might be from stephen@xxxxxxxxxxxxxxxxxx are queue-4.15/uio_hv_generic-check-that-host-supports-monitor-page.patch