Index: bhyve.8
===================================================================
--- bhyve.8	(revision 265363)
+++ bhyve.8	(working copy)
@@ -35,7 +35,7 @@
 .Op Fl aehwxAHPW
 .Op Fl c Ar numcpus
 .Op Fl g Ar gdbport
-.Op Fl p Ar pinnedcpu
+.Op Fl p Ar vcpu:hostcpu
 .Op Fl s Ar slot,emulation Ns Op , Ns Ar conf
 .Op Fl l Ar lpcdev Ns Op , Ns Ar conf
 .Ar vmname
@@ -80,12 +80,11 @@
 allow a remote kernel kgdb to be relayed to the guest kernel gdb stub
 via a local IPv4 address and this port.
 This option will be deprecated in a future version.
-.It Fl p Ar pinnedcpu
-Force guest virtual CPUs to be pinned to host CPUs.
-Virtual CPU
-.Em n
-is pinned to host CPU
-.Em pinnedcpu+n .
+.It Fl p Ar vcpu:hostcpu
+Pin guest's virtual CPU
+.Em vcpu
+to
+.Em hostcpu .
 .It Fl P
 Force the guest virtual CPU to exit when a PAUSE instruction is detected.
 .It Fl W
Index: bhyverun.c
===================================================================
--- bhyverun.c	(revision 265366)
+++ bhyverun.c	(working copy)
@@ -85,7 +85,6 @@
 int guest_ncpus;
 char *guest_uuid_str;
 
-static int pincpu = -1;
 static int guest_vmexit_on_hlt, guest_vmexit_on_pause;
 static int virtio_msix = 1;
 static int x2apic_mode = 0;	/* default is xAPIC */
@@ -123,18 +122,20 @@
 	int		mt_vcpu;	
 } mt_vmm_info[VM_MAXCPU];
 
+static cpuset_t *vcpumap[VM_MAXCPU] = { NULL };
+
 static void
 usage(int code)
 {
 
         fprintf(stderr,
-                "Usage: %s [-aehwAHIPW] [-g <gdb port>] [-s <pci>]\n"
-		"       %*s [-c vcpus] [-p pincpu] [-m mem] [-l <lpc>] <vm>\n"
+                "Usage: %s [-aehwAHIPW] [-g <gdb port>] [-s <pci>] [-c vcpus]\n"
+		"       %*s [-p vcpu:hostcpu] [-m mem] [-l <lpc>] <vm>\n"
 		"       -a: local apic is in xAPIC mode (deprecated)\n"
 		"       -A: create an ACPI table\n"
 		"       -g: gdb port\n"
 		"       -c: # cpus (default 1)\n"
-		"       -p: pin vcpu 'n' to host cpu 'pincpu + n'\n"
+		"       -p: pin 'vcpu' to 'hostcpu'\n"
 		"       -H: vmexit from the guest on hlt\n"
 		"       -P: vmexit from the guest on pause\n"
 		"       -W: force virtio to use single-vector MSI\n"
@@ -152,6 +153,39 @@
 	exit(code);
 }
 
+static int
+pincpu_parse(const char *opt)
+{
+	int vcpu, pcpu;
+
+	if (sscanf(opt, "%d:%d", &vcpu, &pcpu) != 2) {
+		fprintf(stderr, "invalid format: %s\n", opt);
+		return (-1);
+	}
+
+	if (vcpu < 0 || vcpu >= VM_MAXCPU) {
+		fprintf(stderr, "vcpu '%d' outside valid range from 0 to %d\n",
+		    vcpu, VM_MAXCPU - 1);
+		return (-1);
+	}
+
+	if (pcpu < 0 || pcpu >= CPU_SETSIZE) {
+		fprintf(stderr, "hostcpu '%d' outside valid range from "
+		    "0 to %d\n", pcpu, CPU_SETSIZE - 1);
+		return (-1);
+	}
+
+	if (vcpumap[vcpu] == NULL) {
+		if ((vcpumap[vcpu] = malloc(sizeof(cpuset_t))) == NULL) {
+			perror("malloc");
+			return (-1);
+		}
+		CPU_ZERO(vcpumap[vcpu]);
+	}
+	CPU_SET(pcpu, vcpumap[vcpu]);
+	return (0);
+}
+
 void *
 paddr_guest2host(struct vmctx *ctx, uintptr_t gaddr, size_t len)
 {
@@ -498,16 +532,13 @@
 static void
 vm_loop(struct vmctx *ctx, int vcpu, uint64_t rip)
 {
-	cpuset_t mask;
 	int error, rc, prevcpu;
 	enum vm_exitcode exitcode;
 	enum vm_suspend_how how;
 
-	if (pincpu >= 0) {
-		CPU_ZERO(&mask);
-		CPU_SET(pincpu + vcpu, &mask);
+	if (vcpumap[vcpu] != NULL) {
 		error = pthread_setaffinity_np(pthread_self(),
-					       sizeof(mask), &mask);
+		    sizeof(cpuset_t), vcpumap[vcpu]);
 		assert(error == 0);
 	}
 
@@ -640,7 +671,10 @@
 			bvmcons = 1;
 			break;
 		case 'p':
-			pincpu = atoi(optarg);
+                        if (pincpu_parse(optarg) != 0) {
+                            errx(EX_USAGE, "invalid vcpu pinning "
+                                 "configuration '%s'", optarg);
+                        }
 			break;
                 case 'c':
 			guest_ncpus = atoi(optarg);