[PATCH v2 6/7] Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation

From: Dexuan Cui <decui@microsoft.com>
To: "linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
	"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	"sashal@kernel.org" <sashal@kernel.org>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	KY Srinivasan <kys@microsoft.com>,
	Michael Kelley <mikelley@microsoft.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Dexuan Cui <decui@microsoft.com>
Subject: [PATCH v2 6/7] Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation
Date: Wed, 31 Jul 2019 17:52:06 +0000	[thread overview]
Message-ID: <1564595464-56520-7-git-send-email-decui@microsoft.com> (raw)
In-Reply-To: <1564595464-56520-1-git-send-email-decui@microsoft.com>

Before Linux enters hibernation, it sends the CHANNELMSG_UNLOAD message to
the host so all the offers are gone. After hibernation, Linux needs to
re-negotiate with the host using the same vmbus protocol version (which
was in use before hibernation), and ask the host to re-offer the vmbus
devices.

Signed-off-by: Dexuan Cui <decui@microsoft.com>
---
 drivers/hv/connection.c   |  3 +--
 drivers/hv/hyperv_vmbus.h |  2 ++
 drivers/hv/vmbus_drv.c    | 50 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 09829e1..806319c 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -59,8 +59,7 @@ static __u32 vmbus_get_next_version(__u32 current_version)
 	}
 }
 
-static int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo,
-					__u32 version)
+int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version)
 {
 	int ret = 0;
 	unsigned int cur_cpu;
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index 26ea161..e657197 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -274,6 +274,8 @@ struct vmbus_msginfo {
 
 extern struct vmbus_connection vmbus_connection;
 
+int vmbus_negotiate_version(struct vmbus_channel_msginfo *msginfo, u32 version);
+
 static inline void vmbus_send_interrupt(u32 relid)
 {
 	sync_set_bit(relid, vmbus_connection.send_int_page);
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 2ef375c..ca6f4c8 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2043,6 +2043,51 @@ static int vmbus_acpi_add(struct acpi_device *device)
 	return ret_val;
 }
 
+static int vmbus_bus_suspend(struct device *dev)
+{
+	vmbus_initiate_unload(false);
+
+	vmbus_connection.conn_state = DISCONNECTED;
+
+	return 0;
+}
+
+static int vmbus_bus_resume(struct device *dev)
+{
+	struct vmbus_channel_msginfo *msginfo;
+	size_t msgsize;
+	int ret;
+
+	/*
+	 * We only use the 'vmbus_proto_version', which was in use before
+	 * hibernation, to re-negotiate with the host.
+	 */
+	if (vmbus_proto_version == VERSION_INVAL ||
+	    vmbus_proto_version == 0) {
+		pr_err("Invalid proto version = 0x%x\n", vmbus_proto_version);
+		return -EINVAL;
+	}
+
+	msgsize = sizeof(*msginfo) +
+		  sizeof(struct vmbus_channel_initiate_contact);
+
+	msginfo = kzalloc(msgsize, GFP_KERNEL);
+
+	if (msginfo == NULL)
+		return -ENOMEM;
+
+	ret = vmbus_negotiate_version(msginfo, vmbus_proto_version);
+
+	kfree(msginfo);
+
+	if (ret != 0)
+		return ret;
+
+	vmbus_request_offers();
+
+	return 0;
+}
+
 static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 	{"VMBUS", 0},
 	{"VMBus", 0},
@@ -2050,6 +2095,10 @@ static int vmbus_acpi_add(struct acpi_device *device)
 };
 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
 
+static const struct dev_pm_ops vmbus_bus_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(vmbus_bus_suspend, vmbus_bus_resume)
+};
+
 static struct acpi_driver vmbus_acpi_driver = {
 	.name = "vmbus",
 	.ids = vmbus_acpi_device_ids,
@@ -2057,6 +2106,7 @@ static int vmbus_acpi_add(struct acpi_device *device)
 		.add = vmbus_acpi_add,
 		.remove = vmbus_acpi_remove,
 	},
+	.drv.pm = &vmbus_bus_pm,
 };
 
 static void hv_kexec_handler(void)
-- 
1.8.3.1

