From: Long Li <lon...@microsoft.com>
Hyper-V may offer a non latency sensitive device with subchannels without
monitor bit enabled. The decision is entirely on the Hyper-V host not
configurable within guest.
When a device has subchannels, also signal events for the subchannel
if its monitor bit is disabled.
Signed-off-by: Long Li <lon...@microsoft.com>
---
Change log
v2: Use vmbus_set_event() to avoid additional check on monitored bit
Lock vmbus_connection.channel_mutex when going through subchannels
drivers/uio/uio_hv_generic.c | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 3976360d0096..45be2f8baade 100644
--- a/drivers/uio/uio_hv_generic.c
+++ b/drivers/uio/uio_hv_generic.c
@@ -65,6 +65,16 @@ struct hv_uio_private_data {
char send_name[32];
};
+static void set_event(struct vmbus_channel *channel, s32 irq_state)
+{
+ channel->inbound.ring_buffer->interrupt_mask = !irq_state;
+ if (!channel->offermsg.monitor_allocated && irq_state) {
+ /* MB is needed for host to see the interrupt mask first */
+ virt_mb();
+ vmbus_set_event(channel);
+ }
+}
+
/*
* This is the irqcontrol callback to be registered to uio_info.
* It can be used to disable/enable interrupt from user space processes.
@@ -79,12 +89,15 @@ hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
{
struct hv_uio_private_data *pdata = info->priv;
struct hv_device *dev = pdata->device;
+ struct vmbus_channel *primary, *sc;
- dev->channel->inbound.ring_buffer->interrupt_mask = !irq_state;
- virt_mb();
+ primary = dev->channel;
+ set_event(primary, irq_state);
- if (!dev->channel->offermsg.monitor_allocated && irq_state)
- vmbus_setevent(dev->channel);
+ mutex_lock(&vmbus_connection.channel_mutex);
+ list_for_each_entry(sc, &primary->sc_list, sc_list)
+ set_event(sc, irq_state);
+ mutex_unlock(&vmbus_connection.channel_mutex);
return 0;
}
@@ -95,12 +108,19 @@ hv_uio_irqcontrol(struct uio_info *info, s32 irq_state)
static void hv_uio_channel_cb(void *context)
{
struct vmbus_channel *chan = context;
- struct hv_device *hv_dev = chan->device_obj;
- struct hv_uio_private_data *pdata = hv_get_drvdata(hv_dev);
+ struct hv_device *hv_dev;
+ struct hv_uio_private_data *pdata;
chan->inbound.ring_buffer->interrupt_mask = 1;
virt_mb();
+ /*
+ * The callback may come from a subchannel, in which case look
+ * for the hv device in the primary channel
+ */
+ hv_dev = chan->primary_channel ?
+ chan->primary_channel->device_obj : chan->device_obj;
+ pdata = hv_get_drvdata(hv_dev);
uio_event_notify(&pdata->info);
}
--
2.34.1
