On Fri, Feb 28, 2025 at 02:14:14PM -0800, [email protected] wrote: > From: Long Li <[email protected]> > > 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 <[email protected]> > --- > 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();
Why is memory barrier not getting called for 'faster' channels ? - Saurabh
