linux-kernel - [PATCH v2 04/13] x86/kvm/emulate: Introduce COP2R

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Message-ID: <20250430112349.419161890@infradead.org>
Date: Wed, 30 Apr 2025 13:07:38 +0200
From: Peter Zijlstra <peterz@...radead.org>
To: x86@...nel.org
Cc: kys@...rosoft.com,
 haiyangz@...rosoft.com,
 wei.liu@...nel.org,
 decui@...rosoft.com,
 tglx@...utronix.de,
 mingo@...hat.com,
 bp@...en8.de,
 dave.hansen@...ux.intel.com,
 hpa@...or.com,
 seanjc@...gle.com,
 pbonzini@...hat.com,
 ardb@...nel.org,
 kees@...nel.org,
 Arnd Bergmann <arnd@...db.de>,
 gregkh@...uxfoundation.org,
 jpoimboe@...nel.org,
 peterz@...radead.org,
 linux-hyperv@...r.kernel.org,
 linux-kernel@...r.kernel.org,
 kvm@...r.kernel.org,
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 samitolvanen@...gle.com,
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Subject: [PATCH v2 04/13] x86/kvm/emulate: Introduce COP2R

Replace the FASTOP2R instruction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 arch/x86/kvm/emulate.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -326,6 +326,15 @@ static int em_##op(struct x86_emulate_ct
 	ON64(case 8: COP_ASM2(op##q, rax, rdx); break;) \
 	COP_END
 
+/* 2-operand, reversed */
+#define COP2R(op, name) \
+	COP_START(name) \
+	case 1: COP_ASM2(op##b, dl, al); break; \
+	case 2: COP_ASM2(op##w, dx, ax); break; \
+	case 4: COP_ASM2(op##l, edx, eax); break; \
+	ON64(case 8: COP_ASM2(op##q, rdx, rax); break;) \
+	COP_END
+
 /*
  * fastop functions have a special calling convention:
  *
@@ -1077,8 +1086,7 @@ FASTOP2W(bts);
 FASTOP2W(btr);
 FASTOP2W(btc);
 
-
-FASTOP2R(cmp, cmp_r);
+COP2R(cmp, cmp_r);
 
 static int em_bsf_c(struct x86_emulate_ctxt *ctxt)
 {
@@ -4336,12 +4344,12 @@ static const struct opcode opcode_table[
 	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 */