vmd(8): disambiguate log messages per vm and device.

The logging output from vmd(8) often specifies the function performing
the logging, but leaves which vm or vm device to guesswork and
reading tea leaves.

Change the logging formatting to prefix with information about the
specific vm and potentially the device subprocess. Most of this
logging is behind the "verbose" mode, but for warnings this will
clarify which vm or device logged the warning.

The format of vm/<name>/<device><index> is chosen to be concise and
less ugly than other approaches. This adjusts the process naming
for devices to match, dropping the use of brackets.

In the process of this change, updating log settings dynamically
via vmctl(8) is fixed by properly broadcasting that information to
the device subprocesses. The "vmm" process also now updates its own
state properly, so settings survive vm reboots.

ok mlarkin@

1 files changed, 11 insertions, 5 deletions

diff --git a/usr.sbin/vmd/vioblk.c b/usr.sbin/vmd/vioblk.c
index a74348441fa..4dbd7f129ad 100644
--- a/usr.sbin/vmd/vioblk.c
+++ b/usr.sbin/vmd/vioblk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vioblk.c,v 1.8 2023/09/14 15:25:43 dv Exp $	*/
+/*	$OpenBSD: vioblk.c,v 1.9 2023/09/26 01:53:54 dv Exp $	*/
 
 /*
  * Copyright (c) 2023 Dave Voutila <dv@openbsd.org>
@@ -75,8 +75,6 @@ vioblk_main(int fd, int fd_vmm)
 	off_t			 szp = 0;
 	int			 i, ret, type;
 
-	log_procinit("vioblk");
-
 	/*
 	 * stdio - needed for read/write to disk fds and channels to the vm.
 	 * vmm + proc - needed to create shared vm mappings.
@@ -118,7 +116,9 @@ vioblk_main(int fd, int fd_vmm)
 	}
 	vcp = &vm.vm_params.vmc_params;
 	current_vm = &vm;
-	setproctitle("%s/vioblk[%d]", vcp->vcp_name, vioblk->idx);
+
+	setproctitle("%s/vioblk%d", vcp->vcp_name, vioblk->idx);
+	log_procinit("vm/%s/vioblk%d", vcp->vcp_name, vioblk->idx);
 
 	/* Now that we have our vm information, we can remap memory. */
 	ret = remap_guest_mem(&vm, fd_vmm);
@@ -154,7 +154,7 @@ vioblk_main(int fd, int fd_vmm)
 		goto fail;
 	}
 	vioblk->capacity = szp / 512;
-	log_debug("%s: initialized vioblk[%d] with %s image (capacity=%lld)",
+	log_debug("%s: initialized vioblk%d with %s image (capacity=%lld)",
 	    __func__, vioblk->idx, disk_type(type), vioblk->capacity);
 
 	/* If we're restoring hardware, reinitialize the virtqueue hva. */
@@ -434,6 +434,7 @@ dev_dispatch_vm(int fd, short event, void *arg)
 	struct imsgbuf		*ibuf = &iev->ibuf;
 	struct imsg	 	 imsg;
 	ssize_t			 n = 0;
+	int			 verbose;
 
 	if (event & EV_READ) {
 		if ((n = imsg_read(ibuf)) == -1 && errno != EAGAIN)
@@ -472,6 +473,11 @@ dev_dispatch_vm(int fd, short event, void *arg)
 		case IMSG_VMDOP_UNPAUSE_VM:
 			log_debug("%s: unpausing", __func__);
 			break;
+		case IMSG_CTL_VERBOSE:
+			IMSG_SIZE_CHECK(&imsg, &verbose);
+			memcpy(&verbose, imsg.data, sizeof(verbose));
+			log_setverbose(verbose);
+			break;
 		default:
 			log_warnx("%s: unhandled imsg type %d", __func__,
 			    imsg.hdr.type);