[src/trunk]: src/sys/arch/x86/x86 return early from identify_hypervisor() if ...

[bouyer <bouyer%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/cd8af8ddc03c
branches:  trunk
changeset: 953337:cd8af8ddc03c
user:      bouyer <bouyer%NetBSD.org@localhost>
date:      Sat Mar 06 19:16:45 2021 +0000

description:
return early from identify_hypervisor() if we already know we're running
Xen PV or PVH, as this was before 1.119.
Trying to read the BIOS faults (as expected, as there's no BIOS in this case).
Problem pointed out and fix tested by Brian Marcotte

diffstat:

 sys/arch/x86/x86/identcpu.c |  22 +++++++++-------------
 1 files changed, 9 insertions(+), 13 deletions(-)

diffs (44 lines):

diff -r 19c922abbc14 -r cd8af8ddc03c sys/arch/x86/x86/identcpu.c
--- a/sys/arch/x86/x86/identcpu.c       Sat Mar 06 17:56:33 2021 +0000
+++ b/sys/arch/x86/x86/identcpu.c       Sat Mar 06 19:16:45 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: identcpu.c,v 1.119 2021/02/19 02:15:24 christos Exp $  */
+/*     $NetBSD: identcpu.c,v 1.120 2021/03/06 19:16:45 bouyer Exp $    */
 
 /*-
  * Copyright (c) 1999, 2000, 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.119 2021/02/19 02:15:24 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: identcpu.c,v 1.120 2021/03/06 19:16:45 bouyer Exp $");
 
 #include "opt_xen.h"
 
@@ -1135,18 +1135,14 @@
        const char *p;
        int i;
 
-#if 0  
-       /* 
-        * This is called from cpu_probe() and cpu_configure()
-        * During cpu_probe() we have not called platform_init()
-        * yet, so the bios tables have not been loaded.
-        * We allow this to be called twice in order to override
-        * the cpuid setting because some hypervisors don't return
-        * specific enough info with cpuid it.
-        */
-       if (vm_guest != VM_GUEST_NO)
+       switch(vm_guest) {
+       case VM_GUEST_XENPV:
+       case VM_GUEST_XENPVH:
+               /* guest type already known, no bios info */
                return;
-#endif
+       default:
+               break;
+       }
 
        /*
         * [RFC] CPUID usage for interaction between Hypervisors and Linux.