[src/trunk]: src/sys/dev/nvmm/x86 nvmm-x86-vmx: fix detection of the BIOS lock

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

details:   https://anonhg.NetBSD.org/src/rev/0c801de6a55e
branches:  trunk
changeset: 1013167:0c801de6a55e
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sat Aug 22 11:01:10 2020 +0000

description:
nvmm-x86-vmx: fix detection of the BIOS lock

If it's locked, ensure it's locked with VMX enabled. If it's not locked,
then lock it ourselves with VMX enabled.

Should fix NetBSD PR/55596.

diffstat:

 sys/dev/nvmm/x86/nvmm_x86_vmx.c |  23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diffs (51 lines):

diff -r f95bcd1dbf56 -r 0c801de6a55e sys/dev/nvmm/x86/nvmm_x86_vmx.c
--- a/sys/dev/nvmm/x86/nvmm_x86_vmx.c   Sat Aug 22 11:00:00 2020 +0000
+++ b/sys/dev/nvmm/x86/nvmm_x86_vmx.c   Sat Aug 22 11:01:10 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nvmm_x86_vmx.c,v 1.71 2020/08/20 11:09:56 maxv Exp $   */
+/*     $NetBSD: nvmm_x86_vmx.c,v 1.72 2020/08/22 11:01:10 maxv Exp $   */
 
 /*
  * Copyright (c) 2018-2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_vmx.c,v 1.71 2020/08/20 11:09:56 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_vmx.c,v 1.72 2020/08/22 11:01:10 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -3192,11 +3192,8 @@
        }
 
        msr = rdmsr(MSR_IA32_FEATURE_CONTROL);
-       if ((msr & IA32_FEATURE_CONTROL_LOCK) == 0) {
-               printf("NVMM: VMX disabled in BIOS\n");
-               return false;
-       }
-       if ((msr & IA32_FEATURE_CONTROL_OUT_SMX) == 0) {
+       if ((msr & IA32_FEATURE_CONTROL_LOCK) != 0 &&
+           (msr & IA32_FEATURE_CONTROL_OUT_SMX) == 0) {
                printf("NVMM: VMX disabled in BIOS\n");
                return false;
        }
@@ -3322,7 +3319,17 @@
 {
        struct cpu_info *ci = curcpu();
        bool enable = arg1 != NULL;
-       uint64_t cr4;
+       uint64_t msr, cr4;
+
+       if (enable) {
+               msr = rdmsr(MSR_IA32_FEATURE_CONTROL);
+               if ((msr & IA32_FEATURE_CONTROL_LOCK) == 0) {
+                       /* Lock now, with VMX-outside-SMX enabled. */
+                       wrmsr(MSR_IA32_FEATURE_CONTROL, msr |
+                           IA32_FEATURE_CONTROL_LOCK |
+                           IA32_FEATURE_CONTROL_OUT_SMX);
+               }
+       }
 
        if (!enable) {
                vmx_vmxoff();