Replace the FASTOP1SRC2*() instructions.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
 arch/x86/kvm/emulate.c |   34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -317,6 +317,24 @@ static int em_##op(struct x86_emulate_ct
 	ON64(case 8: __EM_ASM_1(op##q, rax); break;) \
 	EM_ASM_END
 
+/* 1-operand, using "c" (src2) */
+#define EM_ASM_1SRC2(op, name) \
+	EM_ASM_START(name) \
+	case 1: __EM_ASM_1(op##b, cl); break; \
+	case 2: __EM_ASM_1(op##w, cx); break; \
+	case 4: __EM_ASM_1(op##l, ecx); break; \
+	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
+	EM_ASM_END
+
+/* 1-operand, using "c" (src2) with exception */
+#define EM_ASM_1SRC2EX(op, name) \
+	EM_ASM_START(name) \
+	case 1: __EM_ASM_1_EX(op##b, cl); break; \
+	case 2: __EM_ASM_1_EX(op##w, cx); break; \
+	case 4: __EM_ASM_1_EX(op##l, ecx); break; \
+	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
+	EM_ASM_END
+
 /* 2-operand, using "a" (dst), "d" (src) */
 #define EM_ASM_2(op) \
 	EM_ASM_START(op) \
@@ -1074,10 +1092,10 @@ EM_ASM_2(cmp);
 EM_ASM_2(test);
 EM_ASM_2(xadd);
 
-FASTOP1SRC2(mul, mul_ex);
-FASTOP1SRC2(imul, imul_ex);
-FASTOP1SRC2EX(div, div_ex);
-FASTOP1SRC2EX(idiv, idiv_ex);
+EM_ASM_1SRC2(mul, mul_ex);
+EM_ASM_1SRC2(imul, imul_ex);
+EM_ASM_1SRC2EX(div, div_ex);
+EM_ASM_1SRC2EX(idiv, idiv_ex);
 
 FASTOP3WCL(shld);
 FASTOP3WCL(shrd);
@@ -4103,10 +4121,10 @@ static const struct opcode group3[] = {
 	I(DstMem | SrcImm | NoWrite, em_test),
 	I(DstMem | SrcNone | Lock, em_not),
 	I(DstMem | SrcNone | Lock, em_neg),
-	F(DstXacc | Src2Mem, em_mul_ex),
-	F(DstXacc | Src2Mem, em_imul_ex),
-	F(DstXacc | Src2Mem, em_div_ex),
-	F(DstXacc | Src2Mem, em_idiv_ex),
+	I(DstXacc | Src2Mem, em_mul_ex),
+	I(DstXacc | Src2Mem, em_imul_ex),
+	I(DstXacc | Src2Mem, em_div_ex),
+	I(DstXacc | Src2Mem, em_idiv_ex),
 };
 
 static const struct opcode group4[] = {

For all of the KVM patches, please use

  KVM: x86:

"x86/kvm" is used for guest-side code, and while I hope no one will conflate this
with guest code, the consistency is helpful.

On Mon, Jul 14, 2025, Peter Zijlstra wrote:
> Replace the FASTOP1SRC2*() instructions.
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
>  arch/x86/kvm/emulate.c |   34 ++++++++++++++++++++++++++--------
>  1 file changed, 26 insertions(+), 8 deletions(-)
> 
> --- a/arch/x86/kvm/emulate.c
> +++ b/arch/x86/kvm/emulate.c
> @@ -317,6 +317,24 @@ static int em_##op(struct x86_emulate_ct
>  	ON64(case 8: __EM_ASM_1(op##q, rax); break;) \
>  	EM_ASM_END
>  
> +/* 1-operand, using "c" (src2) */
> +#define EM_ASM_1SRC2(op, name) \
> +	EM_ASM_START(name) \
> +	case 1: __EM_ASM_1(op##b, cl); break; \
> +	case 2: __EM_ASM_1(op##w, cx); break; \
> +	case 4: __EM_ASM_1(op##l, ecx); break; \
> +	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
> +	EM_ASM_END
> +
> +/* 1-operand, using "c" (src2) with exception */
> +#define EM_ASM_1SRC2EX(op, name) \
> +	EM_ASM_START(name) \
> +	case 1: __EM_ASM_1_EX(op##b, cl); break; \
> +	case 2: __EM_ASM_1_EX(op##w, cx); break; \
> +	case 4: __EM_ASM_1_EX(op##l, ecx); break; \
> +	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \

This needs to be __EM_ASM_1_EX().  Luckily, KVM-Unit-Tests actually has testcase
for divq (somewhere in the morass of testcases).  I also now have an extension to
the fastops selftest to explicitly test all four flavors of div-by-zero; I'll get
it posted tomorrow.

(also, don't also me how long it took me to spot the copy+paste typo; I was full
 on debugging the exception fixup code before I realized my local diff looked
 "odd", *sigh*)

On Wed, Jul 23, 2025 at 05:16:38PM -0700, Sean Christopherson wrote:
> For all of the KVM patches, please use
> 
>   KVM: x86:
> 
> "x86/kvm" is used for guest-side code, and while I hope no one will conflate this
> with guest code, the consistency is helpful.

Sure.

> On Mon, Jul 14, 2025, Peter Zijlstra wrote:
> > Replace the FASTOP1SRC2*() instructions.
> > 
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > ---
> >  arch/x86/kvm/emulate.c |   34 ++++++++++++++++++++++++++--------
> >  1 file changed, 26 insertions(+), 8 deletions(-)
> > 
> > --- a/arch/x86/kvm/emulate.c
> > +++ b/arch/x86/kvm/emulate.c
> > @@ -317,6 +317,24 @@ static int em_##op(struct x86_emulate_ct
> >  	ON64(case 8: __EM_ASM_1(op##q, rax); break;) \
> >  	EM_ASM_END
> >  
> > +/* 1-operand, using "c" (src2) */
> > +#define EM_ASM_1SRC2(op, name) \
> > +	EM_ASM_START(name) \
> > +	case 1: __EM_ASM_1(op##b, cl); break; \
> > +	case 2: __EM_ASM_1(op##w, cx); break; \
> > +	case 4: __EM_ASM_1(op##l, ecx); break; \
> > +	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
> > +	EM_ASM_END
> > +
> > +/* 1-operand, using "c" (src2) with exception */
> > +#define EM_ASM_1SRC2EX(op, name) \
> > +	EM_ASM_START(name) \
> > +	case 1: __EM_ASM_1_EX(op##b, cl); break; \
> > +	case 2: __EM_ASM_1_EX(op##w, cx); break; \
> > +	case 4: __EM_ASM_1_EX(op##l, ecx); break; \
> > +	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
> 
> This needs to be __EM_ASM_1_EX().  Luckily, KVM-Unit-Tests actually has testcase
> for divq (somewhere in the morass of testcases).  I also now have an extension to
> the fastops selftest to explicitly test all four flavors of div-by-zero; I'll get
> it posted tomorrow.
> 
> (also, don't also me how long it took me to spot the copy+paste typo; I was full
>  on debugging the exception fixup code before I realized my local diff looked
>  "odd", *sigh*)

Urgh, sorry about that. Typically I use regex for these things, clearly
I messed up here.

Thanks and fixed!

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

Commit-ID:     af4fe07aa1e07610d3208a85210b896c87e2105e
Gitweb:        https://git.kernel.org/tip/af4fe07aa1e07610d3208a85210b896c87e2105e
Author:        Peter Zijlstra <peterz@infradead.org>
AuthorDate:    Sat, 26 Apr 2025 12:40:12 +02:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 18 Aug 2025 14:23:06 +02:00

KVM: x86: Introduce EM_ASM_1SRC2

Replace the FASTOP1SRC2*() instructions.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lkml.kernel.org/r/20250714103440.394654786@infradead.org
---
 arch/x86/kvm/emulate.c | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9a78540..beac2f4 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -317,6 +317,24 @@ static int em_##op(struct x86_emulate_ctxt *ctxt) \
 	ON64(case 8: __EM_ASM_1(op##q, rax); break;) \
 	EM_ASM_END
 
+/* 1-operand, using "c" (src2) */
+#define EM_ASM_1SRC2(op, name) \
+	EM_ASM_START(name) \
+	case 1: __EM_ASM_1(op##b, cl); break; \
+	case 2: __EM_ASM_1(op##w, cx); break; \
+	case 4: __EM_ASM_1(op##l, ecx); break; \
+	ON64(case 8: __EM_ASM_1(op##q, rcx); break;) \
+	EM_ASM_END
+
+/* 1-operand, using "c" (src2) with exception */
+#define EM_ASM_1SRC2EX(op, name) \
+	EM_ASM_START(name) \
+	case 1: __EM_ASM_1_EX(op##b, cl); break; \
+	case 2: __EM_ASM_1_EX(op##w, cx); break; \
+	case 4: __EM_ASM_1_EX(op##l, ecx); break; \
+	ON64(case 8: __EM_ASM_1_EX(op##q, rcx); break;) \
+	EM_ASM_END
+
 /* 2-operand, using "a" (dst), "d" (src) */
 #define EM_ASM_2(op) \
 	EM_ASM_START(op) \
@@ -1074,10 +1092,10 @@ EM_ASM_2(cmp);
 EM_ASM_2(test);
 EM_ASM_2(xadd);
 
-FASTOP1SRC2(mul, mul_ex);
-FASTOP1SRC2(imul, imul_ex);
-FASTOP1SRC2EX(div, div_ex);
-FASTOP1SRC2EX(idiv, idiv_ex);
+EM_ASM_1SRC2(mul, mul_ex);
+EM_ASM_1SRC2(imul, imul_ex);
+EM_ASM_1SRC2EX(div, div_ex);
+EM_ASM_1SRC2EX(idiv, idiv_ex);
 
 FASTOP3WCL(shld);
 FASTOP3WCL(shrd);
@@ -4103,10 +4121,10 @@ static const struct opcode group3[] = {
 	I(DstMem | SrcImm | NoWrite, em_test),
 	I(DstMem | SrcNone | Lock, em_not),
 	I(DstMem | SrcNone | Lock, em_neg),
-	F(DstXacc | Src2Mem, em_mul_ex),
-	F(DstXacc | Src2Mem, em_imul_ex),
-	F(DstXacc | Src2Mem, em_div_ex),
-	F(DstXacc | Src2Mem, em_idiv_ex),
+	I(DstXacc | Src2Mem, em_mul_ex),
+	I(DstXacc | Src2Mem, em_imul_ex),
+	I(DstXacc | Src2Mem, em_div_ex),
+	I(DstXacc | Src2Mem, em_idiv_ex),
 };
 
 static const struct opcode group4[] = {