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 1b800fc..1f979cb 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -1178,6 +1178,8 @@
twobyte_insn:
switch (b) {
case 0x01: /* lgdt, lidt, lmsw */
+ /* Disable writeback. */
+ no_wb = 1;
switch (modrm_reg) {
u16 size;
unsigned long address;