linux-kernel - [tip: x86/core] KVM: x86: Introduce EM_ASM

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Message-ID: <175568275833.1420.2447057313197360538.tip-bot2@tip-bot2>
Date: Wed, 20 Aug 2025 09:39:18 -0000
From: "tip-bot2 for Peter Zijlstra" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: "Peter Zijlstra (Intel)" <peterz@...radead.org>,
 Sean Christopherson <seanjc@...gle.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject: [tip: x86/core] KVM: x86: Introduce EM_ASM_2R

The following commit has been merged into the x86/core branch of tip:

Commit-ID:     2df2b52c98db03c10ebe93fa270b1e2baf47f8a0
Gitweb:        https://git.kernel.org/tip/2df2b52c98db03c10ebe93fa270b1e2baf47f8a0
Author:        Peter Zijlstra <peterz@...radead.org>
AuthorDate:    Sat, 26 Apr 2025 12:52:05 +02:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Mon, 18 Aug 2025 14:23:05 +02:00

KVM: x86: Introduce EM_ASM_2R

Replace the FASTOP2R instruction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Acked-by: Sean Christopherson <seanjc@...gle.com>
Link: https://lkml.kernel.org/r/20250714103440.024933524@infradead.org
---
 arch/x86/kvm/emulate.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index ec4793f..7af30ef 100644
--- a/arch/x86/kvm/emulate.c
+++ b/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 */