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Commit 4e62417b authored by Aurelien Jarno's avatar Aurelien Jarno Committed by Avi Kivity
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KVM: x86 emulator: fix access registers for instructions with ModR/M byte and Mod = 3 



The patch belows changes the access type to register from memory for
instructions that are declared as SrcMem or DstMem, but have a
ModR/M byte with Mod = 3.

It fixes (at least) the lmsw and smsw instructions on an AMD64 CPU,
which are needed for FreeBSD.

Signed-off-by: default avatarAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 78f78268

drivers/kvm/x86_emulate.c

+16 −0
Original line number Diff line number Diff line
@@ -825,6 +825,14 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
		if (twobyte && b == 0x01 && modrm_reg == 7)

			break;

	      srcmem_common:

		/*

		 * For instructions with a ModR/M byte, switch to register

		 * access if Mod = 3.

		 */

		if ((d & ModRM) && modrm_mod == 3) {

			src.type = OP_REG;

			break;

		}

		src.type = OP_MEM;

		src.ptr = (unsigned long *)cr2;

		src.val = 0;
@@ -893,6 +901,14 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops) 
		dst.ptr = (unsigned long *)cr2;

		dst.bytes = (d & ByteOp) ? 1 : op_bytes;

		dst.val = 0;

		/*

		 * For instructions with a ModR/M byte, switch to register

		 * access if Mod = 3.

		 */

		if ((d & ModRM) && modrm_mod == 3) {

			dst.type = OP_REG;

			break;

		}

		if (d & BitOp) {

			unsigned long mask = ~(dst.bytes * 8 - 1);