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Commit ed9aad21 authored by Nadav Amit's avatar Nadav Amit Committed by Paolo Bonzini
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KVM: x86: MOVNTI emulation min opsize is not respected 



Commit 3b32004a ("KVM: x86: movnti minimum op size of 32-bit is not kept")
did not fully fix the minimum operand size of MONTI emulation. Still, MOVNTI
may be mistakenly performed using 16-bit opsize.

This patch add No16 flag to mark an instruction does not support 16-bits
operand size.

Signed-off-by: default avatarNadav Amit <namit@cs.technion.ac.il>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7f187922

arch/x86/kvm/emulate.c

+7 −7
Original line number Diff line number Diff line
@@ -167,6 +167,7 @@ 
#define NoBigReal   ((u64)1 << 50)  /* No big real mode */

#define PrivUD      ((u64)1 << 51)  /* #UD instead of #GP on CPL > 0 */

#define NearBranch  ((u64)1 << 52)  /* Near branches */

#define No16	    ((u64)1 << 53)  /* No 16 bit operand */



#define DstXacc     (DstAccLo | SrcAccHi | SrcWrite)
@@ -4134,7 +4135,7 @@ static const struct opcode twobyte_table[256] = { 
	D(DstReg | SrcMem8 | ModRM | Mov), D(DstReg | SrcMem16 | ModRM | Mov),

	/* 0xC0 - 0xC7 */

	F2bv(DstMem | SrcReg | ModRM | SrcWrite | Lock, em_xadd),

	N, D(DstMem | SrcReg | ModRM | Mov),

	N, I(DstMem | SrcReg | ModRM | No16 | Mov, em_mov),

	N, N, N, GD(0, &group9),

	/* 0xC8 - 0xCF */

	X8(I(DstReg, em_bswap)),
@@ -4571,7 +4572,8 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) 
		return EMULATION_FAILED;



	if (unlikely(ctxt->d &

	    (NotImpl|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm|NearBranch))) {

	    (NotImpl|Stack|Op3264|Sse|Mmx|Intercept|CheckPerm|NearBranch|

	     No16))) {

		/*

		 * These are copied unconditionally here, and checked unconditionally

		 * in x86_emulate_insn.
@@ -4596,6 +4598,9 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) 
				ctxt->op_bytes = 4;

		}



		if ((ctxt->d & No16) && ctxt->op_bytes == 2)

			ctxt->op_bytes = 4;



		if (ctxt->d & Sse)

			ctxt->op_bytes = 16;

		else if (ctxt->d & Mmx)
@@ -5061,11 +5066,6 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) 
		ctxt->dst.val = (ctxt->src.bytes == 1) ? (s8) ctxt->src.val :

							(s16) ctxt->src.val;

		break;

	case 0xc3:		/* movnti */

		ctxt->dst.bytes = ctxt->op_bytes;

		ctxt->dst.val = (ctxt->op_bytes == 8) ? (u64) ctxt->src.val :

							(u32) ctxt->src.val;

		break;

	default:

		goto cannot_emulate;

	}