From: Aurelien Jarno <aurelien@aurel32.net>
Date: Wed, 25 Jul 2007 08:19:54 +0000 (+0200)
Subject: KVM: disable writeback for 0x0f 0x01 instructions.
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d37c85571904a622cbabc7a2e04b8c919de75ac0;p=linux-beck.git

KVM: disable writeback for 0x0f 0x01 instructions.

0x0f 0x01 instructions (ie lgdt, lidt, smsw, lmsw and invlpg) does
not use writeback. This patch set no_wb=1 when emulating those
instructions.

This fixes a regression booting the FreeBSD kernel on AMD.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Avi Kivity <avi@qumranet.com>
---

diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index 1b800fc00342..1f979cb0df31 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -1178,6 +1178,8 @@ pop_instruction:
 twobyte_insn:
 	switch (b) {
 	case 0x01: /* lgdt, lidt, lmsw */
+		/* Disable writeback. */
+		no_wb = 1;
 		switch (modrm_reg) {
 			u16 size;
 			unsigned long address;