Tools: New ACRNCTL command "blkrescan"

This patch adds support for new acrnctl command blkrescan.
Purpose: To add a virtio-blk device to guest VM after launch.
Use case:
1. Anticipate number of block devices that will be needed
   and add empty backend file while launching VM.
   e.g: -s 5, virtio-blk,nodisk
2. Use the following acrnctl command to trigger
   a rescan of virtio-blk device by guest VM, to
   revalidate and update the backend file.
   “acrnctl blkrescan VMname slot,newfilepath”

v5 -> v6:
- Removed unsed #define
- Reduced the size of param len of blkrescan command
  from 512 to 256.

v2 -> v5:
- No change

v1 -> v2:
- Renamed the acrnctl command and APIs from diskplug
  to blkrescan.
- Split the patch into two. This corresponds to
  changes in tools.

Tracked-On: #3051
Signed-off-by: Vijay Dhanraj <vijay.dhanraj@intel.com>
Reviewed-by: Yu Wang <yu1.wang@intel.com>

tools/acrn-manager/acrn_mngr.h

@@ -19,11 +19,18 @@
 #define ACRN_DM_BASE_PATH	"/run/acrn"
 #define ACRN_DM_SOCK_PATH	"/run/acrn/mngr"
 
+/* TODO: Revisit PARAM_LEN and see if size can be reduced */
+#define PARAM_LEN	256
+
 struct mngr_msg {
 	unsigned long long magic;	/* Make sure you get a mngr_msg */
 	unsigned int msgid;
 	unsigned long timestamp;
 	union {
+
+		/* Arguments to rescan virtio-blk device */
+		char devargs[PARAM_LEN];
+
 		/* ack of DM_STOP, DM_SUSPEND, DM_RESUME, DM_PAUSE, DM_CONTINUE,
 		   ACRND_TIMER, ACRND_STOP, ACRND_RESUME, RTC_TIMER */
 		int err;
@@ -82,6 +89,7 @@ enum dm_msgid {
 	DM_PAUSE,		/* Freeze this virtual machine */
 	DM_CONTINUE,		/* Unfreeze this virtual machine */
 	DM_QUERY,		/* Ask power state of this UOS */
+	DM_BLKRESCAN,		/* Rescan virtio-blk device for any changes in UOS */
 	DM_MAX,
 };
 

tools/acrn-manager/acrn_vm_ops.c

@@ -456,3 +456,22 @@ int resume_vm(const char *vmname, unsigned reason)
 
 	return ack.data.err;
 }
+
+int blkrescan_vm(const char *vmname, char *devargs)
+{
+	struct mngr_msg req;
+	struct mngr_msg ack;
+
+	req.magic = MNGR_MSG_MAGIC;
+	req.msgid = DM_BLKRESCAN;
+	req.timestamp = time(NULL);
+	strncpy(req.data.devargs, devargs, strlen(devargs)+1);
+
+	send_msg(vmname, &req, &ack);
+
+	if (ack.data.err) {
+		printf("Unable to rescan virtio-blk device in vm. errno(%d)\n", ack.data.err);
+	}
+
+	return ack.data.err;
+}

tools/acrn-manager/acrnctl.c

@@ -1,5 +1,5 @@
 /*
- * ProjectAcrn 
+ * ProjectAcrn
  * Acrnctl
  *
  * Copyright (C) 2018 Intel Corporation. All rights reserved.
@@ -37,6 +37,10 @@
 #define SUSPEND_DESC   "Switch virtual machine to suspend state"
 #define RESUME_DESC    "Resume virtual machine from suspend state"
 #define RESET_DESC     "Stop and then start virtual machine VM_NAME"
+#define BLKRESCAN_DESC  "Rescan virtio-blk device attached to a virtual machine"
+
+#define VM_NAME (1)
+#define CMD_ARGS (2)
 
 #define STOP_TIMEOUT	30U
 
@@ -415,6 +419,26 @@ static int acrnctl_do_add(int argc, char *argv[])
 	return ret;
 }
 
+static int acrnctl_do_blkrescan(int argc, char *argv[])
+{
+	struct vmmngr_struct *s;
+
+	s = vmmngr_find(argv[VM_NAME]);
+	if (!s) {
+		printf("can't find %s\n", argv[VM_NAME]);
+		return -1;
+	}
+	if (s->state != VM_STARTED) {
+		printf("%s is in %s state but should be in %s state for blockrescan\n",
+			argv[VM_NAME], state_str[s->state], state_str[VM_STARTED]);
+		return -1;
+	}
+
+	blkrescan_vm(argv[VM_NAME], argv[CMD_ARGS]);
+
+	return 0;
+}
+
 static int acrnctl_do_stop(int argc, char *argv[])
 {
 	struct vmmngr_struct *s;
@@ -702,6 +726,18 @@ int df_valid_args(struct acrnctl_cmd *cmd, int argc, char *argv[])
 	return 0;
 }
 
+static int valid_blkrescan_args(struct acrnctl_cmd *cmd, int argc, char *argv[])
+{
+	char df_opt[] = "VM_NAME slot,newpath";
+
+	if (argc != 3 || !strcmp(argv[1], "help")) {
+		printf("acrnctl %s %s\n", cmd->cmd, df_opt);
+		return -1;
+	}
+
+	return 0;
+}
+
 static int valid_add_args(struct acrnctl_cmd *cmd, int argc, char *argv[])
 {
 	char df_opt[32] = "launch_scripts options";
@@ -747,6 +783,7 @@ struct acrnctl_cmd acmds[] = {
 	ACMD("suspend", acrnctl_do_suspend, SUSPEND_DESC, df_valid_args),
 	ACMD("resume", acrnctl_do_resume, RESUME_DESC, df_valid_args),
 	ACMD("reset", acrnctl_do_reset, RESET_DESC, df_valid_args),
+	ACMD("blkrescan", acrnctl_do_blkrescan, BLKRESCAN_DESC, valid_blkrescan_args),
 };
 
 #define NCMD	(sizeof(acmds)/sizeof(struct acrnctl_cmd))

tools/acrn-manager/acrnctl.h

@@ -59,5 +59,6 @@ int pause_vm(const char *vmname);
 int continue_vm(const char *vmname);
 int suspend_vm(const char *vmname);
 int resume_vm(const char *vmname, unsigned reason);
+int blkrescan_vm(const char *vmname, char *devargs);
 
 #endif				/* _ACRNCTL_H_ */