10 files changed, 277 insertions, 32 deletions

diff --git a/lib/libvmmapi/vmmapi.c b/lib/libvmmapi/vmmapi.c
index ecb21f0dcdc12..cb19bc71b160b 100644
--- a/lib/libvmmapi/vmmapi.c
+++ b/lib/libvmmapi/vmmapi.c
@@ -1506,6 +1506,38 @@ vm_restart_instruction(void *arg, int vcpu)
 }
 
 int
+vm_set_topology(struct vmctx *ctx,
+    uint16_t sockets, uint16_t cores, uint16_t threads, uint16_t maxcpus)
+{
+	struct vm_cpu_topology topology;
+
+	bzero(&topology, sizeof (struct vm_cpu_topology));
+	topology.sockets = sockets;
+	topology.cores = cores;
+	topology.threads = threads;
+	topology.maxcpus = maxcpus;
+	return (ioctl(ctx->fd, VM_SET_TOPOLOGY, &topology));
+}
+
+int
+vm_get_topology(struct vmctx *ctx,
+    uint16_t *sockets, uint16_t *cores, uint16_t *threads, uint16_t *maxcpus)
+{
+	struct vm_cpu_topology topology;
+	int error;
+
+	bzero(&topology, sizeof (struct vm_cpu_topology));
+	error = ioctl(ctx->fd, VM_GET_TOPOLOGY, &topology);
+	if (error == 0) {
+		*sockets = topology.sockets;
+		*cores = topology.cores;
+		*threads = topology.threads;
+		*maxcpus = topology.maxcpus;
+	}
+	return (error);
+}
+
+int
 vm_get_device_fd(struct vmctx *ctx)
 {
 
@@ -1535,7 +1567,7 @@ vm_get_ioctls(size_t *len)
 	    VM_ACTIVATE_CPU, VM_GET_CPUS, VM_SUSPEND_CPU, VM_RESUME_CPU,
 	    VM_SET_INTINFO, VM_GET_INTINFO,
 	    VM_RTC_WRITE, VM_RTC_READ, VM_RTC_SETTIME, VM_RTC_GETTIME,
-	    VM_RESTART_INSTRUCTION };
+	    VM_RESTART_INSTRUCTION, VM_SET_TOPOLOGY, VM_GET_TOPOLOGY };
 
 	if (len == NULL) {
 		cmds = malloc(sizeof(vm_ioctl_cmds));
diff --git a/lib/libvmmapi/vmmapi.h b/lib/libvmmapi/vmmapi.h
index da7267cba59d7..9819cda16bd93 100644
--- a/lib/libvmmapi/vmmapi.h
+++ b/lib/libvmmapi/vmmapi.h
@@ -221,6 +221,12 @@ int	vm_activate_cpu(struct vmctx *ctx, int vcpu);
 int	vm_suspend_cpu(struct vmctx *ctx, int vcpu);
 int	vm_resume_cpu(struct vmctx *ctx, int vcpu);
 
+/* CPU topology */
+int	vm_set_topology(struct vmctx *ctx, uint16_t sockets, uint16_t cores,
+	    uint16_t threads, uint16_t maxcpus);
+int	vm_get_topology(struct vmctx *ctx, uint16_t *sockets, uint16_t *cores,
+	    uint16_t *threads, uint16_t *maxcpus);
+
 /*
  * FreeBSD specific APIs
  */
diff --git a/sys/amd64/include/vmm.h b/sys/amd64/include/vmm.h
index 4951362f8c145..43e6db2d9cbd2 100644
--- a/sys/amd64/include/vmm.h
+++ b/sys/amd64/include/vmm.h
@@ -181,6 +181,10 @@ int vm_create(const char *name, struct vm **retvm);
 void vm_destroy(struct vm *vm);
 int vm_reinit(struct vm *vm);
 const char *vm_name(struct vm *vm);
+void vm_get_topology(struct vm *vm, uint16_t *sockets, uint16_t *cores,
+    uint16_t *threads, uint16_t *maxcpus);
+int vm_set_topology(struct vm *vm, uint16_t sockets, uint16_t cores,
+    uint16_t threads, uint16_t maxcpus);
 
 /*
  * APIs that modify the guest memory map require all vcpus to be frozen.
diff --git a/sys/amd64/include/vmm_dev.h b/sys/amd64/include/vmm_dev.h
index abddf1de3a2f6..d77320dcaef76 100644
--- a/sys/amd64/include/vmm_dev.h
+++ b/sys/amd64/include/vmm_dev.h
@@ -226,6 +226,13 @@ struct vm_rtc_data {
 	uint8_t		value;
 };
 
+struct vm_cpu_topology {
+	uint16_t	sockets;
+	uint16_t	cores;
+	uint16_t	threads;
+	uint16_t	maxcpus;
+};
+
 enum {
 	/* general routines */
 	IOCNUM_ABIVERS = 0,
@@ -284,6 +291,10 @@ enum {
 	IOCNUM_GET_X2APIC_STATE = 61,
 	IOCNUM_GET_HPET_CAPABILITIES = 62,
 
+	/* CPU Topology */
+	IOCNUM_SET_TOPOLOGY = 63,
+	IOCNUM_GET_TOPOLOGY = 64,
+
 	/* legacy interrupt injection */
 	IOCNUM_ISA_ASSERT_IRQ = 80,
 	IOCNUM_ISA_DEASSERT_IRQ = 81,
@@ -379,6 +390,10 @@ enum {
 	_IOWR('v', IOCNUM_GET_X2APIC_STATE, struct vm_x2apic)
 #define	VM_GET_HPET_CAPABILITIES \
 	_IOR('v', IOCNUM_GET_HPET_CAPABILITIES, struct vm_hpet_cap)
+#define VM_SET_TOPOLOGY \
+	_IOW('v', IOCNUM_SET_TOPOLOGY, struct vm_cpu_topology)
+#define VM_GET_TOPOLOGY \
+	_IOR('v', IOCNUM_GET_TOPOLOGY, struct vm_cpu_topology)
 #define	VM_GET_GPA_PMAP \
 	_IOWR('v', IOCNUM_GET_GPA_PMAP, struct vm_gpa_pte)
 #define	VM_GLA2GPA	\
diff --git a/sys/amd64/vmm/vmm.c b/sys/amd64/vmm/vmm.c
index 7a520affe9c8b..538baa4171fa9 100644
--- a/sys/amd64/vmm/vmm.c
+++ b/sys/amd64/vmm/vmm.c
@@ -166,6 +166,11 @@ struct vm {
 	struct vmspace	*vmspace;		/* (o) guest's address space */
 	char		name[VM_MAX_NAMELEN];	/* (o) virtual machine name */
 	struct vcpu	vcpu[VM_MAXCPU];	/* (i) guest vcpus */
+	/* The following describe the vm cpu topology */
+	uint16_t	sockets;		/* (o) num of sockets */
+	uint16_t	cores;			/* (o) num of cores/socket */
+	uint16_t	threads;		/* (o) num of threads/core */
+	uint16_t	maxcpus;		/* (o) max pluggable cpus */
 };
 
 static int vmm_initialized;
@@ -425,6 +430,12 @@ vm_init(struct vm *vm, bool create)
 		vcpu_init(vm, i, create);
 }
 
+/*
+ * The default CPU topology is a single thread per package.
+ */
+u_int cores_per_package = 1;
+u_int threads_per_core = 1;
+
 int
 vm_create(const char *name, struct vm **retvm)
 {
@@ -450,12 +461,43 @@ vm_create(const char *name, struct vm **retvm)
 	vm->vmspace = vmspace;
 	mtx_init(&vm->rendezvous_mtx, "vm rendezvous lock", 0, MTX_DEF);
 
+	vm->sockets = 1;
+	vm->cores = cores_per_package;	/* XXX backwards compatibility */
+	vm->threads = threads_per_core;	/* XXX backwards compatibility */
+	vm->maxcpus = 0;		/* XXX not implemented */
+
 	vm_init(vm, true);
 
 	*retvm = vm;
 	return (0);
 }
 
+void
+vm_get_topology(struct vm *vm, uint16_t *sockets, uint16_t *cores,
+    uint16_t *threads, uint16_t *maxcpus)
+{
+	*sockets = vm->sockets;
+	*cores = vm->cores;
+	*threads = vm->threads;
+	*maxcpus = vm->maxcpus;
+}
+
+int
+vm_set_topology(struct vm *vm, uint16_t sockets, uint16_t cores,
+    uint16_t threads, uint16_t maxcpus)
+{
+	if (maxcpus != 0)
+		return (EINVAL);	/* XXX remove when supported */
+	if ((sockets * cores * threads) > VM_MAXCPU)
+		return (EINVAL);
+	/* XXX need to check sockets * cores * threads == vCPU, how? */
+	vm->sockets = sockets;
+	vm->cores = cores;
+	vm->threads = threads;
+	vm->maxcpus = maxcpus;
+	return(0);
+}
+
 static void
 vm_cleanup(struct vm *vm, bool destroy)
 {
diff --git a/sys/amd64/vmm/vmm_dev.c b/sys/amd64/vmm/vmm_dev.c
index ab8a55b3c6847..ba033ef0bc6aa 100644
--- a/sys/amd64/vmm/vmm_dev.c
+++ b/sys/amd64/vmm/vmm_dev.c
@@ -346,6 +346,7 @@ vmmdev_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 	struct vm_rtc_time *rtctime;
 	struct vm_rtc_data *rtcdata;
 	struct vm_memmap *mm;
+	struct vm_cpu_topology *topology;
 	uint64_t *regvals;
 	int *regnums;
 
@@ -737,6 +738,17 @@ vmmdev_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
 	case VM_RESTART_INSTRUCTION:
 		error = vm_restart_instruction(sc->vm, vcpu);
 		break;
+	case VM_SET_TOPOLOGY:
+		topology = (struct vm_cpu_topology *)data;
+		error = vm_set_topology(sc->vm, topology->sockets,
+		    topology->cores, topology->threads, topology->maxcpus);
+		break;
+	case VM_GET_TOPOLOGY:
+		topology = (struct vm_cpu_topology *)data;
+		vm_get_topology(sc->vm, &topology->sockets, &topology->cores,
+		    &topology->threads, &topology->maxcpus);
+		error = 0;
+		break;
 	default:
 		error = ENOTTY;
 		break;
diff --git a/sys/amd64/vmm/x86.c b/sys/amd64/vmm/x86.c
index 106932d579935..4aecc4a4a518c 100644
--- a/sys/amd64/vmm/x86.c
+++ b/sys/amd64/vmm/x86.c
@@ -60,16 +60,15 @@ static uint64_t bhyve_xcpuids;
 SYSCTL_ULONG(_hw_vmm, OID_AUTO, bhyve_xcpuids, CTLFLAG_RW, &bhyve_xcpuids, 0,
     "Number of times an unknown cpuid leaf was accessed");
 
-/*
- * The default CPU topology is a single thread per package.
- */
-static u_int threads_per_core = 1;
+#if __FreeBSD_version < 1200060	/* Remove after 11 EOL helps MFCing */
+extern u_int threads_per_core;
 SYSCTL_UINT(_hw_vmm_topology, OID_AUTO, threads_per_core, CTLFLAG_RDTUN,
     &threads_per_core, 0, NULL);
 
-static u_int cores_per_package = 1;
+extern u_int cores_per_package;
 SYSCTL_UINT(_hw_vmm_topology, OID_AUTO, cores_per_package, CTLFLAG_RDTUN,
     &cores_per_package, 0, NULL);
+#endif
 
 static int cpuid_leaf_b = 1;
 SYSCTL_INT(_hw_vmm_topology, OID_AUTO, cpuid_leaf_b, CTLFLAG_RDTUN,
@@ -95,6 +94,7 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 	int error, enable_invpcid, level, width, x2apic_id;
 	unsigned int func, regs[4], logical_cpus;
 	enum x2apic_state x2apic_state;
+	uint16_t cores, maxcpus, sockets, threads;
 
 	VCPU_CTR2(vm, vcpu_id, "cpuid %#x,%#x", *eax, *ecx);
 
@@ -142,11 +142,11 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 				 *
 				 * However this matches the logical cpus as
 				 * advertised by leaf 0x1 and will work even
-				 * if the 'threads_per_core' tunable is set
-				 * incorrectly on an AMD host.
+				 * if threads is set incorrectly on an AMD host.
 				 */
-				logical_cpus = threads_per_core *
-				    cores_per_package;
+				vm_get_topology(vm, &sockets, &cores, &threads,
+				    &maxcpus);
+				logical_cpus = threads * cores;
 				regs[2] = logical_cpus - 1;
 			}
 			break;
@@ -305,7 +305,9 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 			 */
 			regs[3] |= (CPUID_MCA | CPUID_MCE | CPUID_MTRR);
 
-			logical_cpus = threads_per_core * cores_per_package;
+			vm_get_topology(vm, &sockets, &cores, &threads,
+			    &maxcpus);
+			logical_cpus = threads * cores;
 			regs[1] &= ~CPUID_HTT_CORES;
 			regs[1] |= (logical_cpus & 0xff) << 16;
 			regs[3] |= CPUID_HTT;
@@ -315,8 +317,10 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 			cpuid_count(*eax, *ecx, regs);
 
 			if (regs[0] || regs[1] || regs[2] || regs[3]) {
+				vm_get_topology(vm, &sockets, &cores, &threads,
+				    &maxcpus);
 				regs[0] &= 0x3ff;
-				regs[0] |= (cores_per_package - 1) << 26;
+				regs[0] |= (cores - 1) << 26;
 				/*
 				 * Cache topology:
 				 * - L1 and L2 are shared only by the logical
@@ -324,10 +328,10 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 				 * - L3 and above are shared by all logical
 				 *   processors in the package.
 				 */
-				logical_cpus = threads_per_core;
+				logical_cpus = threads;
 				level = (regs[0] >> 5) & 0x7;
 				if (level >= 3)
-					logical_cpus *= cores_per_package;
+					logical_cpus *= cores;
 				regs[0] |= (logical_cpus - 1) << 14;
 			}
 			break;
@@ -389,16 +393,17 @@ x86_emulate_cpuid(struct vm *vm, int vcpu_id,
 			/*
 			 * Processor topology enumeration
 			 */
+			vm_get_topology(vm, &sockets, &cores, &threads,
+			    &maxcpus);
 			if (*ecx == 0) {
-				logical_cpus = threads_per_core;
+				logical_cpus = threads;
 				width = log2(logical_cpus);
 				level = CPUID_TYPE_SMT;
 				x2apic_id = vcpu_id;
 			}
 
 			if (*ecx == 1) {
-				logical_cpus = threads_per_core *
-				    cores_per_package;
+				logical_cpus = threads * cores;
 				width = log2(logical_cpus);
 				level = CPUID_TYPE_CORE;
 				x2apic_id = vcpu_id;
diff --git a/usr.sbin/bhyve/bhyve.8 b/usr.sbin/bhyve/bhyve.8
index 77f36e28f5245..8c259b0000513 100644
--- a/usr.sbin/bhyve/bhyve.8
+++ b/usr.sbin/bhyve/bhyve.8
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd June 2, 2017
+.Dd April 6, 2018
 .Dt BHYVE 8
 .Os
 .Sh NAME
@@ -33,7 +33,16 @@
 .Sh SYNOPSIS
 .Nm
 .Op Fl abehuwxACHPSWY
-.Op Fl c Ar numcpus
+.Oo
+.Fl c\~ Ns
+.Oo
+.Op Ar cpus= Ns
+.Ar numcpus Ns
+.Oc Ns
+.Op Ar ,sockets=n Ns
+.Op Ar ,cores=n Ns
+.Op Ar ,threads=n
+.Oc
 .Op Fl g Ar gdbport
 .Op Fl l Ar lpcdev Ns Op , Ns Ar conf
 .Op Fl m Ar memsize Ns Op Ar K|k|M|m|G|g|T|t
@@ -77,9 +86,30 @@ Enable a low-level console device supported by
 kernels compiled with
 .Cd "device bvmconsole" .
 This option will be deprecated in a future version.
-.It Fl c Ar numcpus
-Number of guest virtual CPUs.
-The default is 1 and the maximum is 16.
+.It Fl c Op Ar setting ...
+Number of guest virtual CPUs
+and/or the CPU topology.
+The default value for each of
+.Ar numcpus ,
+.Ar sockets ,
+.Ar cores ,
+and
+.Ar threads
+is 1.
+The current maximum number of guest virtual CPUs is 16.
+If
+.Ar numcpus
+is not specified then it will be calculated from the other arguments.
+The topology must be consistent in that the
+.Ar numcpus
+must equal the product of
+.Ar sockets ,
+.Ar cores ,
+and
+.Ar threads .
+If a
+.Ar setting
+is specified more than once the last one has precedence.
 .It Fl C
 Include guest memory in core file.
 .It Fl e
diff --git a/usr.sbin/bhyve/bhyverun.c b/usr.sbin/bhyve/bhyverun.c
index b2d271f2309d6..8cad2299291b4 100644
--- a/usr.sbin/bhyve/bhyverun.c
+++ b/usr.sbin/bhyve/bhyverun.c
@@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$");
 #include <pthread_np.h>
 #include <sysexits.h>
 #include <stdbool.h>
+#include <stdint.h>
 
 #include <machine/vmm.h>
 #ifndef WITHOUT_CAPSICUM
@@ -93,6 +94,8 @@ extern int vmexit_task_switch(struct vmctx *, struct vm_exit *, int *vcpu);
 char *vmname;
 
 int guest_ncpus;
+uint16_t cores, maxcpus, sockets, threads;
+
 char *guest_uuid_str;
 
 static int guest_vmexit_on_hlt, guest_vmexit_on_pause;
@@ -137,11 +140,13 @@ usage(int code)
 {
 
         fprintf(stderr,
-                "Usage: %s [-abehuwxACHPSWY] [-c vcpus] [-g <gdb port>] [-l <lpc>]\n"
+		"Usage: %s [-abehuwxACHPSWY]\n"
+		"       %*s [-c [[cpus=]numcpus][,sockets=n][,cores=n][,threads=n]]\n"
+		"       %*s [-g <gdb port>] [-l <lpc>]\n"
 		"       %*s [-m mem] [-p vcpu:hostcpu] [-s <pci>] [-U uuid] <vm>\n"
 		"       -a: local apic is in xAPIC mode (deprecated)\n"
 		"       -A: create ACPI tables\n"
-		"       -c: # cpus (default 1)\n"
+		"       -c: number of cpus and/or topology specification"
 		"       -C: include guest memory in core file\n"
 		"       -e: exit on unhandled I/O access\n"
 		"       -g: gdb port\n"
@@ -159,11 +164,91 @@ usage(int code)
 		"       -W: force virtio to use single-vector MSI\n"
 		"       -x: local apic is in x2APIC mode\n"
 		"       -Y: disable MPtable generation\n",
-		progname, (int)strlen(progname), "");
+		progname, (int)strlen(progname), "", (int)strlen(progname), "",
+		(int)strlen(progname), "");
 
 	exit(code);
 }
 
+/*
+ * XXX This parser is known to have the following issues:
+ * 1.  It accepts null key=value tokens ",,".
+ * 2.  It accepts whitespace after = and before value.
+ * 3.  Values out of range of INT are silently wrapped.
+ * 4.  It doesn't check non-final values.
+ * 5.  The apparently bogus limits of UINT16_MAX are for future expansion.
+ *
+ * The acceptance of a null specification ('-c ""') is by design to match the
+ * manual page syntax specification, this results in a topology of 1 vCPU.
+ */
+static int
+topology_parse(const char *opt)
+{
+	uint64_t ncpus;
+	int c, chk, n, s, t, tmp;
+	char *cp, *str;
+	bool ns, scts;
+
+	c = 1, n = 1, s = 1, t = 1;
+	ns = false, scts = false;
+	str = strdup(opt);
+
+	while ((cp = strsep(&str, ",")) != NULL) {
+		if (sscanf(cp, "%i%n", &tmp, &chk) == 1) {
+			n = tmp;
+			ns = true;
+		} else if (sscanf(cp, "cpus=%i%n", &tmp, &chk) == 1) {
+			n = tmp;
+			ns = true;
+		} else if (sscanf(cp, "sockets=%i%n", &tmp, &chk) == 1) {
+			s = tmp;
+			scts = true;
+		} else if (sscanf(cp, "cores=%i%n", &tmp, &chk) == 1) {
+			c = tmp;
+			scts = true;
+		} else if (sscanf(cp, "threads=%i%n", &tmp, &chk) == 1) {
+			t = tmp;
+			scts = true;
+#ifdef notyet  /* Do not expose this until vmm.ko implements it */
+		} else if (sscanf(cp, "maxcpus=%i%n", &tmp, &chk) == 1) {
+			m = tmp;
+#endif
+		/* Skip the empty argument case from -c "" */
+		} else if (cp[0] == '\0')
+			continue;
+		else
+			return (-1);
+		/* Any trailing garbage causes an error */
+		if (cp[chk] != '\0')
+			return (-1);
+	}
+	/*
+	 * Range check 1 <= n <= UINT16_MAX all values
+	 */
+	if (n < 1 || s < 1 || c < 1 || t < 1 ||
+	    n > UINT16_MAX || s > UINT16_MAX || c > UINT16_MAX  ||
+	    t > UINT16_MAX)
+		return (-1);
+
+	/* If only the cpus was specified, use that as sockets */
+	if (!scts)
+		s = n;
+	/*
+	 * Compute sockets * cores * threads avoiding overflow
+	 * The range check above insures these are 16 bit values
+	 * If n was specified check it against computed ncpus
+	 */
+	ncpus = (uint64_t)s * c * t;
+	if (ncpus > UINT16_MAX || (ns && n != ncpus))
+		return (-1);
+
+	guest_ncpus = ncpus;
+	sockets = s;
+	cores = c;
+	threads = t;
+	return(0);
+}
+
 static int
 pincpu_parse(const char *opt)
 {
@@ -783,6 +868,9 @@ do_open(const char *vmname)
 			exit(1);
 		}
 	}
+	error = vm_set_topology(ctx, sockets, cores, threads, maxcpus);
+	if (error)
+		errx(EX_OSERR, "vm_set_topology");
 	return (ctx);
 }
 
@@ -801,6 +889,8 @@ main(int argc, char *argv[])
 	progname = basename(argv[0]);
 	gdb_port = 0;
 	guest_ncpus = 1;
+	sockets = cores = threads = 1;
+	maxcpus = 0;
 	memsize = 256 * MB;
 	mptgen = 1;
 	rtc_localtime = 1;
@@ -825,7 +915,10 @@ main(int argc, char *argv[])
                         }
 			break;
                 case 'c':
-			guest_ncpus = atoi(optarg);
+			if (topology_parse(optarg) != 0) {
+			    errx(EX_USAGE, "invalid cpu topology "
+				"'%s'", optarg);
+			}
 			break;
 		case 'C':
 			memflags |= VM_MEM_F_INCORE;
@@ -903,11 +996,6 @@ main(int argc, char *argv[])
 	vmname = argv[0];
 	ctx = do_open(vmname);
 
-	if (guest_ncpus < 1) {
-		fprintf(stderr, "Invalid guest vCPUs (%d)\n", guest_ncpus);
-		exit(1);
-	}
-
 	max_vcpus = num_vcpus_allowed(ctx);
 	if (guest_ncpus > max_vcpus) {
 		fprintf(stderr, "%d vCPUs requested but only %d available\n",
diff --git a/usr.sbin/bhyvectl/bhyvectl.c b/usr.sbin/bhyvectl/bhyvectl.c
index d492e0828bcde..42cf7d91a11ab 100644
--- a/usr.sbin/bhyvectl/bhyvectl.c
+++ b/usr.sbin/bhyvectl/bhyvectl.c
@@ -191,7 +191,8 @@ usage(bool cpu_intel)
 	"       [--get-msr-bitmap]\n"
 	"       [--get-msr-bitmap-address]\n"
 	"       [--get-guest-sysenter]\n"
-	"       [--get-exit-reason]\n",
+	"       [--get-exit-reason]\n"
+	"       [--get-cpu-topology]\n",
 	progname);
 
 	if (cpu_intel) {
@@ -285,6 +286,7 @@ static int set_x2apic_state, get_x2apic_state;
 enum x2apic_state x2apic_state;
 static int unassign_pptdev, bus, slot, func;
 static int run;
+static int get_cpu_topology;
 
 /*
  * VMCB specific.
@@ -1456,6 +1458,7 @@ setup_options(bool cpu_intel)
 		{ "get-active-cpus", 	NO_ARG,	&get_active_cpus, 	1 },
 		{ "get-suspended-cpus", NO_ARG,	&get_suspended_cpus, 	1 },
 		{ "get-intinfo", 	NO_ARG,	&get_intinfo,		1 },
+		{ "get-cpu-topology",	NO_ARG, &get_cpu_topology,	1 },
 	};
 
 	const struct option intel_opts[] = {
@@ -2312,6 +2315,14 @@ main(int argc, char *argv[])
 		}
 	}
 
+	if (!error && (get_cpu_topology || get_all)) {
+		uint16_t sockets, cores, threads, maxcpus;
+
+		vm_get_topology(ctx, &sockets, &cores, &threads, &maxcpus);
+		printf("cpu_topology:\tsockets=%hu, cores=%hu, threads=%hu, "
+		    "maxcpus=%hu\n", sockets, cores, threads, maxcpus);
+	}
+
 	if (!error && run) {
 		error = vm_run(ctx, vcpu, &vmexit);
 		if (error == 0)