Commit 547fa4ff authored by Saurabh Sengar's avatar Saurabh Sengar Committed by Greg Kroah-Hartman
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uio_hv_generic: Enable interrupt for low speed VMBus devices 



Hyper-V is adding some "specialty" synthetic devices. Instead of writing
new kernel-level VMBus drivers for these devices, the devices will be
presented to user space via this existing Hyper-V generic UIO driver, so
that a user space driver can handle the device. Since these new synthetic
devices are low speed devices, they don't support monitor bits and we must
use vmbus_setevent() to enable interrupts from the host.

Signed-off-by: default avatarSaurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: default avatarLong Li <longli@microsoft.com>
Link: https://lore.kernel.org/r/1711788723-8593-4-git-send-email-ssengar@linux.microsoft.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e566ed5b

drivers/uio/uio_hv_generic.c

+3 −6
Original line number Diff line number Diff line
@@ -84,6 +84,9 @@ hv_uio_irqcontrol(struct uio_info *info, s32 irq_state) 
	dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;

	virt_mb();



	if (!dev->channel->offermsg.monitor_allocated && irq_state)

		vmbus_setevent(dev->channel);



	return 0;

}
@@ -240,12 +243,6 @@ hv_uio_probe(struct hv_device *dev, 
	int ret;

	size_t ring_size = hv_dev_ring_size(channel);



	/* Communicating with host has to be via shared memory not hypercall */

	if (!channel->offermsg.monitor_allocated) {

		dev_err(&dev->device, "vmbus channel requires hypercall\n");

		return -ENOTSUPP;

	}



	if (!ring_size)

		ring_size = HV_RING_SIZE * PAGE_SIZE;