[PATCH v3 2/4] hv_utils: Support host-initiated restart request

From: Dexuan Cui
Date: Sat Jan 25 2020 - 14:55:11 EST


The hv_utils driver currently supports a "shutdown" operation initiated
from the Hyper-V host. Newer versions of Hyper-V also support a "restart"
operation. So add support for the updated protocol version that has
"restart" support, and perform a clean reboot when such a message is
received from Hyper-V.

To test the restart functionality, run this PowerShell command on the
Hyper-V host:

Restart-VM <vmname> -Type Reboot

Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>

---
Changes in v2:
It's the same as v1.

Changes in v3 (I addressed Michael's comments):
Used a better version of changelog from Michael.
Added a comment about the meaning of shutdown_msg->flags.
Call schedule_work() at the end of the function for consistency.

drivers/hv/hv_util.c | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index 766bd8457346..d815bea0fda3 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -24,6 +24,8 @@

#define SD_MAJOR 3
#define SD_MINOR 0
+#define SD_MINOR_1 1
+#define SD_VERSION_3_1 (SD_MAJOR << 16 | SD_MINOR_1)
#define SD_VERSION (SD_MAJOR << 16 | SD_MINOR)

#define SD_MAJOR_1 1
@@ -50,8 +52,9 @@ static int sd_srv_version;
static int ts_srv_version;
static int hb_srv_version;

-#define SD_VER_COUNT 2
+#define SD_VER_COUNT 3
static const int sd_versions[] = {
+ SD_VERSION_3_1,
SD_VERSION,
SD_VERSION_1
};
@@ -118,17 +121,28 @@ static void perform_shutdown(struct work_struct *dummy)
orderly_poweroff(true);
}

+static void perform_restart(struct work_struct *dummy)
+{
+ orderly_reboot();
+}
+
/*
* Perform the shutdown operation in a thread context.
*/
static DECLARE_WORK(shutdown_work, perform_shutdown);

+/*
+ * Perform the restart operation in a thread context.
+ */
+static DECLARE_WORK(restart_work, perform_restart);
+
static void shutdown_onchannelcallback(void *context)
{
struct vmbus_channel *channel = context;
u32 recvlen;
u64 requestid;
bool execute_shutdown = false;
+ bool execute_reboot = false;
u8 *shut_txf_buf = util_shutdown.recv_buffer;

struct shutdown_msg_data *shutdown_msg;
@@ -157,6 +171,12 @@ static void shutdown_onchannelcallback(void *context)
sizeof(struct vmbuspipe_hdr) +
sizeof(struct icmsg_hdr)];

+ /*
+ * shutdown_msg->flags can be 0 (shut down), 2(reboot),
+ * or 4(hibernate). It may bitwise-OR 1, which means
+ * performing the request by force. Linux always tries
+ * to perform the request by force.
+ */
switch (shutdown_msg->flags) {
case 0:
case 1:
@@ -166,6 +186,14 @@ static void shutdown_onchannelcallback(void *context)
pr_info("Shutdown request received -"
" graceful shutdown initiated\n");
break;
+ case 2:
+ case 3:
+ icmsghdrp->status = HV_S_OK;
+ execute_reboot = true;
+
+ pr_info("Restart request received -"
+ " graceful restart initiated\n");
+ break;
default:
icmsghdrp->status = HV_E_FAIL;
execute_shutdown = false;
@@ -186,6 +214,8 @@ static void shutdown_onchannelcallback(void *context)

if (execute_shutdown == true)
schedule_work(&shutdown_work);
+ if (execute_reboot == true)
+ schedule_work(&restart_work);
}

/*
--
2.19.1