[src/trunk]: src/sys/dev/nvmm/x86 Reset DR7 before loading DR0-3, to prevent ...

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

details:   https://anonhg.NetBSD.org/src/rev/7f2cdc857cff
branches:  trunk
changeset: 995982:7f2cdc857cff
user:      maxv <maxv%NetBSD.org@localhost>
date:      Sun Jan 13 10:07:50 2019 +0000

description:
Reset DR7 before loading DR0-3, to prevent a fault if the host process
has dbregs enabled.

diffstat:

 sys/dev/nvmm/x86/nvmm_x86_svm.c |  6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diffs (27 lines):

diff -r c3dd75e08b2d -r 7f2cdc857cff sys/dev/nvmm/x86/nvmm_x86_svm.c
--- a/sys/dev/nvmm/x86/nvmm_x86_svm.c   Sun Jan 13 10:01:07 2019 +0000
+++ b/sys/dev/nvmm/x86/nvmm_x86_svm.c   Sun Jan 13 10:07:50 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nvmm_x86_svm.c,v 1.14 2019/01/10 06:58:36 maxv Exp $   */
+/*     $NetBSD: nvmm_x86_svm.c,v 1.15 2019/01/13 10:07:50 maxv Exp $   */
 
 /*
  * Copyright (c) 2018 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.14 2019/01/10 06:58:36 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nvmm_x86_svm.c,v 1.15 2019/01/13 10:07:50 maxv Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -1128,6 +1128,8 @@
 
        x86_dbregs_save(curlwp);
 
+       ldr7(0);
+
        ldr0(cpudata->drs[NVMM_X64_DR_DR0]);
        ldr1(cpudata->drs[NVMM_X64_DR_DR1]);
        ldr2(cpudata->drs[NVMM_X64_DR_DR2]);