4.15-stable review patch. If anyone has any objections, please let me know.
------------------
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);