linux-kernel - [PATCH] uio_hv_generic: Set event for all channels on the device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <1740617158-15902-1-git-send-email-longli@linuxonhyperv.com>
Date: Wed, 26 Feb 2025 16:45:58 -0800
From: longli@...uxonhyperv.com
To: "K. Y. Srinivasan" <kys@...rosoft.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Wei Liu <wei.liu@...nel.org>,
	Dexuan Cui <decui@...rosoft.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-hyperv@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Long Li <longli@...rosoft.com>
Subject: [PATCH] uio_hv_generic: Set event for all channels on the device

From: Long Li <longli@...rosoft.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 <longli@...rosoft.com>
---
 drivers/uio/uio_hv_generic.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/uio/uio_hv_generic.c b/drivers/uio/uio_hv_generic.c
index 3976360d0096..8b6df598a728 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_setevent(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 +89,13 @@ 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);
+	list_for_each_entry(sc, &primary->sc_list, sc_list)
+		set_event(sc, irq_state);
 
 	return 0;
 }
@@ -95,12 +106,19 @@ 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