Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation

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>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 09829e1..806319c 100644 (file)
--- 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 (file)
--- 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 a30c70a..ce9974b 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2089,6 +2089,51 @@ acpi_walk_err:
        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},
@@ -2096,6 +2141,19 @@ static const struct acpi_device_id vmbus_acpi_device_ids[] = {
 };
 MODULE_DEVICE_TABLE(acpi, vmbus_acpi_device_ids);
 
+/*
+ * Note: we must use SET_NOIRQ_SYSTEM_SLEEP_PM_OPS rather than
+ * SET_SYSTEM_SLEEP_PM_OPS, otherwise NIC SR-IOV can not work, because the
+ * "pci_dev_pm_ops" uses the "noirq" callbacks: in the resume path, the
+ * pci "noirq" restore callback runs before "non-noirq" callbacks (see
+ * resume_target_kernel() -> dpm_resume_start(), and hibernation_restore() ->
+ * dpm_resume_end()). This means vmbus_bus_resume() and the pci-hyperv's
+ * resume callback must also run via the "noirq" callbacks.
+ */
+static const struct dev_pm_ops vmbus_bus_pm = {
+       SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(vmbus_bus_suspend, vmbus_bus_resume)
+};
+
 static struct acpi_driver vmbus_acpi_driver = {
        .name = "vmbus",
        .ids = vmbus_acpi_device_ids,
@@ -2103,6 +2161,7 @@ static struct acpi_driver vmbus_acpi_driver = {
                .add = vmbus_acpi_add,
                .remove = vmbus_acpi_remove,
        },
+       .drv.pm = &vmbus_bus_pm,
 };
 
 static void hv_kexec_handler(void)