Identify hypervisors before configuring other children of the mainbus

(bios, CPU, interrupt handlers, pvbus).  This splits the pvbus attach
function into two parts: pvbus_identify() to scan the CPUID registers
for supported hypervisors and pvbus_attach() to attach the bus, print
information, and configure the children.

This will be needed for Xen and KVM, as discussed with mikeb@ and sf@
OK mlarkin@

2 files changed, 9 insertions, 7 deletions

diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 755d4d09048..bd1fba43bcc 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.577 2015/12/07 06:34:14 jsg Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.578 2015/12/12 12:33:49 reyk Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -2042,11 +2042,6 @@ identifycpu(struct cpu_info *ci)
 		if (ci->ci_feature_sefflags_ebx & SEFF0EBX_SMAP)
 			replacesmap();
 #endif
-
-#if NPVBUS > 0
-		if (cpu_ecxfeature & CPUIDECX_HV)
-			has_hv_cpuid = 1;
-#endif
 	}
 
 #ifndef SMALL_KERNEL
diff --git a/sys/arch/i386/i386/mainbus.c b/sys/arch/i386/i386/mainbus.c
index 218c856f042..c32a41348c4 100644
--- a/sys/arch/i386/i386/mainbus.c
+++ b/sys/arch/i386/i386/mainbus.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mainbus.c,v 1.53 2015/08/20 04:41:46 mlarkin Exp $	*/
+/*	$OpenBSD: mainbus.c,v 1.54 2015/12/12 12:33:49 reyk Exp $	*/
 /*	$NetBSD: mainbus.c,v 1.21 1997/06/06 23:14:20 thorpej Exp $	*/
 
 /*
@@ -36,6 +36,7 @@
 #include <sys/device.h>
 
 #include <machine/bus.h>
+#include <machine/specialreg.h>
 
 #include <dev/isa/isavar.h>
 #include <dev/eisa/eisavar.h>
@@ -142,6 +143,12 @@ mainbus_attach(struct device *parent, struct device *self, void *aux)
 
 	printf("\n");
 
+#if NPVBUS > 0
+	/* Detect hypervisors early, attach the paravirtual bus later */
+	if (cpu_ecxfeature & CPUIDECX_HV)
+		pvbus_identify();
+#endif
+
 #if NBIOS > 0
 	{
 		mba.mba_bios.ba_name = "bios";