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Subject[PATCH v5 6/9] Drivers: hv: vmbus: Suspend/resume the vmbus itself for hibernation
Date
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>
---
drivers/hv/connection.c | 3 +--
drivers/hv/hyperv_vmbus.h | 2 ++
drivers/hv/vmbus_drv.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 62 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 a30c70a..ce9974b 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2089,6 +2089,51 @@ 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},
@@ -2096,6 +2141,19 @@ static int vmbus_acpi_add(struct acpi_device *device)
};
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 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
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