[v2,09/13] x86/kvm/emulate: Convert em_salc() to C

Message ID	20250430112349.963740147@infradead.org
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Headers	show Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDC381DE2A4; Wed, 30 Apr 2025 11:26:46 +0000 (UTC) Message-ID: <20250430112349.963740147@infradead.org> User-Agent: quilt/0.66 Date: Wed, 30 Apr 2025 13:07:43 +0200 From: Peter Zijlstra <peterz@infradead.org> To: x86@kernel.org Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, seanjc@google.com, pbonzini@redhat.com, ardb@kernel.org, kees@kernel.org, Arnd Bergmann <arnd@arndb.de>, gregkh@linuxfoundation.org, jpoimboe@kernel.org, peterz@infradead.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-efi@vger.kernel.org, samitolvanen@google.com, ojeda@kernel.org Subject: [PATCH v2 09/13] x86/kvm/emulate: Convert em_salc() to C References: <20250430110734.392235199@infradead.org> Precedence: bulk MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8
Series	objtool: Detect and warn about indirect calls in __nocfi functions \| expand [v2,00/13] objtool: Detect and warn about indirect calls in __nocfi functions [v2,01/13] x86/kvm/emulate: Implement test_cc() in C [v2,02/13] x86/kvm/emulate: Introduce COP1 [v2,03/13] x86/kvm/emulate: Introduce COP2 [v2,04/13] x86/kvm/emulate: Introduce COP2R [v2,05/13] x86/kvm/emulate: Introduce COP2W [v2,06/13] x86/kvm/emulate: Introduce COP2CL [v2,07/13] x86/kvm/emulate: Introduce COP1SRC2 [v2,08/13] x86/kvm/emulate: Introduce COP3WCL [v2,09/13] x86/kvm/emulate: Convert em_salc() to C [v2,10/13] x86/kvm/emulate: Remove fastops [v2,11/13] x86,hyperv: Clean up hv_do_hypercall() [v2,12/13] x86_64,hyperv: Use direct call to hypercall-page [v2,13/13] objtool: Validate kCFI calls

Message ID

20250430112349.963740147@infradead.org

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New

Headers

Message-ID: <20250430112349.963740147@infradead.org>
User-Agent: quilt/0.66
Date: Wed, 30 Apr 2025 13:07:43 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: kys@microsoft.com,
 haiyangz@microsoft.com,
 wei.liu@kernel.org,
 decui@microsoft.com,
 tglx@linutronix.de,
 mingo@redhat.com,
 bp@alien8.de,
 dave.hansen@linux.intel.com,
 hpa@zytor.com,
 seanjc@google.com,
 pbonzini@redhat.com,
 ardb@kernel.org,
 kees@kernel.org,
 Arnd Bergmann <arnd@arndb.de>,
 gregkh@linuxfoundation.org,
 jpoimboe@kernel.org,
 peterz@infradead.org,
 linux-hyperv@vger.kernel.org,
 linux-kernel@vger.kernel.org,
 kvm@vger.kernel.org,
 linux-efi@vger.kernel.org,
 samitolvanen@google.com,
 ojeda@kernel.org
Subject: [PATCH v2 09/13] x86/kvm/emulate: Convert em_salc() to C
References: <20250430110734.392235199@infradead.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8

Series

objtool: Detect and warn about indirect calls in __nocfi functions | expand

Commit Message

Peter Zijlstra April 30, 2025, 11:07 a.m. UTC

Implement the SALC (Set AL if Carry) instruction in C.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kvm/emulate.c |   15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -529,11 +529,14 @@  static int fastop(struct x86_emulate_ctx
 	ON64(FOP3E(op##q, rax, rdx, cl)) \
 	FOP_END
 
-FOP_START(salc)
-FOP_FUNC(salc)
-"pushf; sbb %al, %al; popf \n\t"
-FOP_RET(salc)
-FOP_END;
+static int em_salc(struct x86_emulate_ctxt *ctxt)
+{
+	/*
+	 * Set AL 0xFF if CF is set, or 0x00 when clear.
+	 */
+	ctxt->dst.val = 0xFF * !!(ctxt->eflags & X86_EFLAGS_CF);
+	return X86EMUL_CONTINUE;
+}
 
 /*
  * XXX: inoutclob user must know where the argument is being expanded.
@@ -4423,7 +4426,7 @@  static const struct opcode opcode_table[
 	G(Src2CL | ByteOp, group2), G(Src2CL, group2),
 	I(DstAcc | SrcImmUByte | No64, em_aam),
 	I(DstAcc | SrcImmUByte | No64, em_aad),
-	F(DstAcc | ByteOp | No64, em_salc),
+	I(DstAcc | ByteOp | No64, em_salc),
 	I(DstAcc | SrcXLat | ByteOp, em_mov),
 	/* 0xD8 - 0xDF */
 	N, E(0, &escape_d9), N, E(0, &escape_db), N, E(0, &escape_dd), N, N,

[v2,09/13] x86/kvm/emulate: Convert em_salc() to C

Commit Message

Patch