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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 10/13] x86/kvm/emulate: Remove fastops
Date: Wed, 30 Apr 2025 13:07:44 +0200	[thread overview]
Message-ID: <20250430112350.085829848@infradead.org> (raw)
In-Reply-To: 20250430110734.392235199@infradead.org

No more FASTOPs, remove the remains.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kvm/emulate.c |  172 -------------------------------------------------
 1 file changed, 1 insertion(+), 171 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -167,7 +167,6 @@
 #define Unaligned   ((u64)2 << 41)  /* Explicitly unaligned (e.g. MOVDQU) */
 #define Avx         ((u64)3 << 41)  /* Advanced Vector Extensions */
 #define Aligned16   ((u64)4 << 41)  /* Aligned to 16 byte boundary (e.g. FXSAVE) */
-#define Fastop      ((u64)1 << 44)  /* Use opcode::u.fastop */
 #define NoWrite     ((u64)1 << 45)  /* No writeback */
 #define SrcWrite    ((u64)1 << 46)  /* Write back src operand */
 #define NoMod	    ((u64)1 << 47)  /* Mod field is ignored */
@@ -203,7 +202,6 @@ struct opcode {
 		const struct escape *esc;
 		const struct instr_dual *idual;
 		const struct mode_dual *mdual;
-		void (*fastop)(struct fastop *fake);
 	} u;
 	int (*check_perm)(struct x86_emulate_ctxt *ctxt);
 };
@@ -383,152 +381,6 @@ static int em_##op(struct x86_emulate_ct
 	ON64(case 8: COP_ASM3(op##q, rax, rdx, cl); break;) \
 	COP_END
 
-
-/*
- * fastop functions have a special calling convention:
- *
- * dst:    rax        (in/out)
- * src:    rdx        (in/out)
- * src2:   rcx        (in)
- * flags:  rflags     (in/out)
- * ex:     rsi        (in:fastop pointer, out:zero if exception)
- *
- * Moreover, they are all exactly FASTOP_SIZE bytes long, so functions for
- * different operand sizes can be reached by calculation, rather than a jump
- * table (which would be bigger than the code).
- *
- * The 16 byte alignment, considering 5 bytes for the RET thunk, 3 for ENDBR
- * and 1 for the straight line speculation INT3, leaves 7 bytes for the
- * body of the function.  Currently none is larger than 4.
- */
-static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
-
-#define FASTOP_SIZE	16
-
-#define __FOP_FUNC(name) \
-	".align " __stringify(FASTOP_SIZE) " \n\t" \
-	".type " name ", @function \n\t" \
-	name ":\n\t" \
-	ASM_ENDBR \
-	IBT_NOSEAL(name)
-
-#define FOP_FUNC(name) \
-	__FOP_FUNC(#name)
-
-#define __FOP_RET(name) \
-	"11: " ASM_RET \
-	".size " name ", .-" name "\n\t"
-
-#define FOP_RET(name) \
-	__FOP_RET(#name)
-
-#define __FOP_START(op, align) \
-	extern void em_##op(struct fastop *fake); \
-	asm(".pushsection .text, \"ax\" \n\t" \
-	    ".global em_" #op " \n\t" \
-	    ".align " __stringify(align) " \n\t" \
-	    "em_" #op ":\n\t"
-
-#define FOP_START(op) __FOP_START(op, FASTOP_SIZE)
-
-#define FOP_END \
-	    ".popsection")
-
-#define __FOPNOP(name) \
-	__FOP_FUNC(name) \
-	__FOP_RET(name)
-
-#define FOPNOP() \
-	__FOPNOP(__stringify(__UNIQUE_ID(nop)))
-
-#define FOP1E(op,  dst) \
-	__FOP_FUNC(#op "_" #dst) \
-	"10: " #op " %" #dst " \n\t" \
-	__FOP_RET(#op "_" #dst)
-
-#define FOP1EEX(op,  dst) \
-	FOP1E(op, dst) _ASM_EXTABLE_TYPE_REG(10b, 11b, EX_TYPE_ZERO_REG, %%esi)
-
-#define FASTOP1(op) \
-	FOP_START(op) \
-	FOP1E(op##b, al) \
-	FOP1E(op##w, ax) \
-	FOP1E(op##l, eax) \
-	ON64(FOP1E(op##q, rax))	\
-	FOP_END
-
-/* 1-operand, using src2 (for MUL/DIV r/m) */
-#define FASTOP1SRC2(op, name) \
-	FOP_START(name) \
-	FOP1E(op, cl) \
-	FOP1E(op, cx) \
-	FOP1E(op, ecx) \
-	ON64(FOP1E(op, rcx)) \
-	FOP_END
-
-/* 1-operand, using src2 (for MUL/DIV r/m), with exceptions */
-#define FASTOP1SRC2EX(op, name) \
-	FOP_START(name) \
-	FOP1EEX(op, cl) \
-	FOP1EEX(op, cx) \
-	FOP1EEX(op, ecx) \
-	ON64(FOP1EEX(op, rcx)) \
-	FOP_END
-
-#define FOP2E(op,  dst, src)	   \
-	__FOP_FUNC(#op "_" #dst "_" #src) \
-	#op " %" #src ", %" #dst " \n\t" \
-	__FOP_RET(#op "_" #dst "_" #src)
-
-#define FASTOP2(op) \
-	FOP_START(op) \
-	FOP2E(op##b, al, dl) \
-	FOP2E(op##w, ax, dx) \
-	FOP2E(op##l, eax, edx) \
-	ON64(FOP2E(op##q, rax, rdx)) \
-	FOP_END
-
-/* 2 operand, word only */
-#define FASTOP2W(op) \
-	FOP_START(op) \
-	FOPNOP() \
-	FOP2E(op##w, ax, dx) \
-	FOP2E(op##l, eax, edx) \
-	ON64(FOP2E(op##q, rax, rdx)) \
-	FOP_END
-
-/* 2 operand, src is CL */
-#define FASTOP2CL(op) \
-	FOP_START(op) \
-	FOP2E(op##b, al, cl) \
-	FOP2E(op##w, ax, cl) \
-	FOP2E(op##l, eax, cl) \
-	ON64(FOP2E(op##q, rax, cl)) \
-	FOP_END
-
-/* 2 operand, src and dest are reversed */
-#define FASTOP2R(op, name) \
-	FOP_START(name) \
-	FOP2E(op##b, dl, al) \
-	FOP2E(op##w, dx, ax) \
-	FOP2E(op##l, edx, eax) \
-	ON64(FOP2E(op##q, rdx, rax)) \
-	FOP_END
-
-#define FOP3E(op,  dst, src, src2) \
-	__FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \
-	#op " %" #src2 ", %" #src ", %" #dst " \n\t"\
-	__FOP_RET(#op "_" #dst "_" #src "_" #src2)
-
-/* 3-operand, word-only, src2=cl */
-#define FASTOP3WCL(op) \
-	FOP_START(op) \
-	FOPNOP() \
-	FOP3E(op##w, ax, dx, cl) \
-	FOP3E(op##l, eax, edx, cl) \
-	ON64(FOP3E(op##q, rax, rdx, cl)) \
-	FOP_END
-
 static int em_salc(struct x86_emulate_ctxt *ctxt)
 {
 	/*
@@ -4052,7 +3904,6 @@ static int check_perm_out(struct x86_emu
 #define MD(_f, _m) { .flags = ((_f) | ModeDual), .u.mdual = (_m) }
 #define E(_f, _e) { .flags = ((_f) | Escape | ModRM), .u.esc = (_e) }
 #define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
-#define F(_f, _e) { .flags = (_f) | Fastop, .u.fastop = (_e) }
 #define II(_f, _e, _i) \
 	{ .flags = (_f)|Intercept, .u.execute = (_e), .intercept = x86_intercept_##_i }
 #define IIP(_f, _e, _i, _p) \
@@ -5158,24 +5009,6 @@ static void fetch_possible_mmx_operand(s
 		kvm_read_mmx_reg(op->addr.mm, &op->mm_val);
 }
 
-static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop)
-{
-	ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF;
-
-	if (!(ctxt->d & ByteOp))
-		fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE;
-
-	asm("push %[flags]; popf; " CALL_NOSPEC " ; pushf; pop %[flags]\n"
-	    : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags),
-	      [thunk_target]"+S"(fop), ASM_CALL_CONSTRAINT
-	    : "c"(ctxt->src2.val));
-
-	ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK);
-	if (!fop) /* exception is returned in fop variable */
-		return emulate_de(ctxt);
-	return X86EMUL_CONTINUE;
-}
-
 void init_decode_cache(struct x86_emulate_ctxt *ctxt)
 {
 	/* Clear fields that are set conditionally but read without a guard. */
@@ -5340,10 +5173,7 @@ int x86_emulate_insn(struct x86_emulate_
 		ctxt->eflags &= ~X86_EFLAGS_RF;
 
 	if (ctxt->execute) {
-		if (ctxt->d & Fastop)
-			rc = fastop(ctxt, ctxt->fop);
-		else
-			rc = ctxt->execute(ctxt);
+		rc = ctxt->execute(ctxt);
 		if (rc != X86EMUL_CONTINUE)
 			goto done;
 		goto writeback;



  parent reply	other threads:[~2025-04-30 11:26 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-30 11:07 [PATCH v2 00/13] objtool: Detect and warn about indirect calls in __nocfi functions Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 01/13] x86/kvm/emulate: Implement test_cc() in C Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 02/13] x86/kvm/emulate: Introduce COP1 Peter Zijlstra
2025-04-30 16:19   ` Josh Poimboeuf
2025-04-30 19:05     ` Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 03/13] x86/kvm/emulate: Introduce COP2 Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 04/13] x86/kvm/emulate: Introduce COP2R Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 05/13] x86/kvm/emulate: Introduce COP2W Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 06/13] x86/kvm/emulate: Introduce COP2CL Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 07/13] x86/kvm/emulate: Introduce COP1SRC2 Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 08/13] x86/kvm/emulate: Introduce COP3WCL Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 09/13] x86/kvm/emulate: Convert em_salc() to C Peter Zijlstra
2025-04-30 11:07 ` Peter Zijlstra [this message]
2025-04-30 11:07 ` [PATCH v2 11/13] x86,hyperv: Clean up hv_do_hypercall() Peter Zijlstra
2025-05-01  2:36   ` Michael Kelley
2025-04-30 11:07 ` [PATCH v2 12/13] x86_64,hyperv: Use direct call to hypercall-page Peter Zijlstra
2025-05-01  2:36   ` Michael Kelley
2025-05-01  8:59     ` Peter Zijlstra
2025-04-30 11:07 ` [PATCH v2 13/13] objtool: Validate kCFI calls Peter Zijlstra
2025-04-30 15:59   ` Josh Poimboeuf
2025-04-30 19:03     ` Peter Zijlstra
2025-05-01 15:56       ` Peter Zijlstra
2025-04-30 14:24 ` [PATCH v2 00/13] objtool: Detect and warn about indirect calls in __nocfi functions H. Peter Anvin
2025-04-30 19:06   ` Peter Zijlstra
2025-05-01 10:30     ` Peter Zijlstra
2025-05-01 15:38       ` Peter Zijlstra
2025-05-01 18:30         ` Sean Christopherson
2025-05-01 18:42           ` H. Peter Anvin
2025-05-01 18:59             ` Sean Christopherson
2025-05-02  6:12               ` Xin Li
2025-05-02  5:46           ` Xin Li
2025-05-02  5:48           ` Xin Li
2025-05-02 19:43             ` H. Peter Anvin
2025-05-02  8:40           ` Peter Zijlstra
2025-05-02 19:53             ` Sean Christopherson
2025-05-03  9:50               ` Peter Zijlstra
2025-05-03 18:28                 ` Josh Poimboeuf
2025-05-06  7:31                   ` Peter Zijlstra
2025-05-06 13:32                     ` Peter Zijlstra
2025-05-06 19:18                       ` Josh Poimboeuf
2025-05-28  7:44                         ` Peter Zijlstra
2025-05-28 16:30                           ` Peter Zijlstra
2025-05-28 16:35                             ` Peter Zijlstra
2025-05-29  9:30                               ` Peter Zijlstra
2025-06-03  5:43                                 ` Josh Poimboeuf
2025-06-03 16:29                                   ` Josh Poimboeuf
2025-06-05 17:19                                     ` Josh Poimboeuf
2025-06-06 10:49                                       ` Peter Zijlstra
2025-06-06 13:15                                         ` Sean Christopherson
2025-06-06 13:20                                           ` Peter Zijlstra
2025-05-01 18:33 ` Paolo Bonzini
2025-05-02 11:08   ` Peter Zijlstra

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