Commit bac27d35 authored Aug 05, 2007 by Avi Kivity Committed by Linus Torvalds Aug 06, 2007

KVM: x86 emulator: fix debug reg mov instructions



More fallout from the writeback fixes: debug register transfer
instructions do their own writeback and thus need to disable the general
writeback mechanism.

This fixes oopses and some guest failures on AMD machines (the Intel
variant decodes the instruction in hardware and thus does not need
emulation).

Cc: Alistair John Strachan <alistair@devzero.co.uk>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 9e865f58

drivers/kvm/x86_emulate.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -1217,11 +1217,13 @@ x86_emulate_memop(struct x86_emulate_ctxt ctxt, struct x86_emulate_ops ops)
		}
		break;
		case 0x21: /* mov from dr to reg */
		no_wb = 1;
		if (modrm_mod != 3)
		goto cannot_emulate;
		rc = emulator_get_dr(ctxt, modrm_reg, &_regs[modrm_rm]);
		break;
		case 0x23: /* mov from reg to dr */
		no_wb = 1;
		if (modrm_mod != 3)
		goto cannot_emulate;
		rc = emulator_set_dr(ctxt, modrm_reg, _regs[modrm_rm]);