linux-kernel - [PATCH 2/3] x86/kvm: Simplify FOP

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Date:   Thu, 18 Aug 2022 08:53:42 -0700
From:   Josh Poimboeuf <jpoimboe@...nel.org>
To:     x86@...nel.org
Cc:     linux-kernel@...r.kernel.org, Pengfei Xu <pengfei.xu@...el.com>,
        "Yang, Weijiang" <weijiang.yang@...el.com>,
        "Su, Heng" <heng.su@...el.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 2/3] x86/kvm: Simplify FOP_SETCC()

SETCC_ALIGN and FOP_ALIGN are both 16.  Remove the special casing for
FOP_SETCC() and just make it a normal fastop.

Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.org>
---
 arch/x86/kvm/emulate.c | 23 ++++-------------------
 1 file changed, 4 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index b4eeb7c75dfa..205d566ebd72 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -446,27 +446,12 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
 	FOP_END
 
 /* Special case for SETcc - 1 instruction per cc */
-
-/*
- * Depending on .config the SETcc functions look like:
- *
- * ENDBR			[4 bytes; CONFIG_X86_KERNEL_IBT]
- * SETcc %al			[3 bytes]
- * RET | JMP __x86_return_thunk	[1,5 bytes; CONFIG_RETHUNK]
- * INT3				[1 byte; CONFIG_SLS]
- */
-#define SETCC_ALIGN	16
-
 #define FOP_SETCC(op) \
-	".align " __stringify(SETCC_ALIGN) " \n\t" \
-	".type " #op ", @function \n\t" \
-	#op ": \n\t" \
-	ASM_ENDBR \
+	FOP_FUNC(op) \
 	#op " %al \n\t" \
-	__FOP_RET(#op) \
-	".skip " __stringify(SETCC_ALIGN) " - (.-" #op "), 0xcc \n\t"
+	FOP_RET(op)
 
-__FOP_START(setcc, SETCC_ALIGN)
+FOP_START(setcc)
 FOP_SETCC(seto)
 FOP_SETCC(setno)
 FOP_SETCC(setc)
@@ -1079,7 +1064,7 @@ static int em_bsr_c(struct x86_emulate_ctxt *ctxt)
 static __always_inline u8 test_cc(unsigned int condition, unsigned long flags)
 {
 	u8 rc;
-	void (*fop)(void) = (void *)em_setcc + SETCC_ALIGN * (condition & 0xf);
+	void (*fop)(void) = (void *)em_setcc + FASTOP_SIZE * (condition & 0xf);
 
 	flags = (flags & EFLAGS_MASK) | X86_EFLAGS_IF;
 	asm("push %[flags]; popf; " CALL_NOSPEC
-- 
2.37.2