KVM: x86: Introduce EM_ASM_2R

Replace the FASTOP2R instruction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/20250714103440.024933524@infradead.org

Author: Peter Zijlstra

arch/x86/kvm/emulate.c

@@ -326,6 +326,15 @@ static int em_##op(struct x86_emulate_ctxt *ctxt) \
 	ON64(case 8: __EM_ASM_2(op##q, rax, rdx); break;) \
 	EM_ASM_END
 
+/* 2-operand, reversed */
+#define EM_ASM_2R(op, name) \
+	EM_ASM_START(name) \
+	case 1: __EM_ASM_2(op##b, dl, al); break; \
+	case 2: __EM_ASM_2(op##w, dx, ax); break; \
+	case 4: __EM_ASM_2(op##l, edx, eax); break; \
+	ON64(case 8: __EM_ASM_2(op##q, rdx, rax); break;) \
+	EM_ASM_END
+
 /*
  * fastop functions have a special calling convention:
  *
@@ -1077,8 +1086,7 @@ FASTOP2W(bts);
 FASTOP2W(btr);
 FASTOP2W(btc);
 
-
-FASTOP2R(cmp, cmp_r);
+EM_ASM_2R(cmp, cmp_r);
 
 static int em_bsf_c(struct x86_emulate_ctxt *ctxt)
 {
@@ -4336,12 +4344,12 @@ static const struct opcode opcode_table[256] = {
 	I2bv(DstAcc | SrcMem | Mov | MemAbs, em_mov),
 	I2bv(DstMem | SrcAcc | Mov | MemAbs | PageTable, em_mov),
 	I2bv(SrcSI | DstDI | Mov | String | TwoMemOp, em_mov),
-	F2bv(SrcSI | DstDI | String | NoWrite | TwoMemOp, em_cmp_r),
+	I2bv(SrcSI | DstDI | String | NoWrite | TwoMemOp, em_cmp_r),
 	/* 0xA8 - 0xAF */
 	I2bv(DstAcc | SrcImm | NoWrite, em_test),
 	I2bv(SrcAcc | DstDI | Mov | String, em_mov),
 	I2bv(SrcSI | DstAcc | Mov | String, em_mov),
-	F2bv(SrcAcc | DstDI | String | NoWrite, em_cmp_r),
+	I2bv(SrcAcc | DstDI | String | NoWrite, em_cmp_r),
 	/* 0xB0 - 0xB7 */
 	X8(I(ByteOp | DstReg | SrcImm | Mov, em_mov)),
 	/* 0xB8 - 0xBF */