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* [PATCH] KVM: SVM/VMX: Use %rax instead of %__ASM_AX within CONFIG_X86_64
@ 2021-05-12 11:21 Uros Bizjak
  2021-05-12 11:58 ` Paolo Bonzini
  0 siblings, 1 reply; 3+ messages in thread
From: Uros Bizjak @ 2021-05-12 11:21 UTC (permalink / raw)
  To: kvm, linux-kernel; +Cc: Uros Bizjak, Paolo Bonzini

There is no need to use %__ASM_AX within CONFIG_X86_64. The macro
will always expand to %rax.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
 arch/x86/kvm/svm/vmenter.S | 44 +++++++++++++++++++-------------------
 arch/x86/kvm/vmx/vmenter.S | 32 +++++++++++++--------------
 2 files changed, 38 insertions(+), 38 deletions(-)

diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 4fa17df123cd..844b558bb021 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -64,14 +64,14 @@ SYM_FUNC_START(__svm_vcpu_run)
 	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
 	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
 #ifdef CONFIG_X86_64
-	mov VCPU_R8 (%_ASM_AX),  %r8
-	mov VCPU_R9 (%_ASM_AX),  %r9
-	mov VCPU_R10(%_ASM_AX), %r10
-	mov VCPU_R11(%_ASM_AX), %r11
-	mov VCPU_R12(%_ASM_AX), %r12
-	mov VCPU_R13(%_ASM_AX), %r13
-	mov VCPU_R14(%_ASM_AX), %r14
-	mov VCPU_R15(%_ASM_AX), %r15
+	mov VCPU_R8 (%rax),  %r8
+	mov VCPU_R9 (%rax),  %r9
+	mov VCPU_R10(%rax), %r10
+	mov VCPU_R11(%rax), %r11
+	mov VCPU_R12(%rax), %r12
+	mov VCPU_R13(%rax), %r13
+	mov VCPU_R14(%rax), %r14
+	mov VCPU_R15(%rax), %r15
 #endif
 
 	/* "POP" @vmcb to RAX. */
@@ -93,21 +93,21 @@ SYM_FUNC_START(__svm_vcpu_run)
 	pop %_ASM_AX
 
 	/* Save all guest registers.  */
-	mov %_ASM_CX,   VCPU_RCX(%_ASM_AX)
-	mov %_ASM_DX,   VCPU_RDX(%_ASM_AX)
-	mov %_ASM_BX,   VCPU_RBX(%_ASM_AX)
-	mov %_ASM_BP,   VCPU_RBP(%_ASM_AX)
-	mov %_ASM_SI,   VCPU_RSI(%_ASM_AX)
-	mov %_ASM_DI,   VCPU_RDI(%_ASM_AX)
+	mov %_ASM_CX, VCPU_RCX(%_ASM_AX)
+	mov %_ASM_DX, VCPU_RDX(%_ASM_AX)
+	mov %_ASM_BX, VCPU_RBX(%_ASM_AX)
+	mov %_ASM_BP, VCPU_RBP(%_ASM_AX)
+	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
+	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
 #ifdef CONFIG_X86_64
-	mov %r8,  VCPU_R8 (%_ASM_AX)
-	mov %r9,  VCPU_R9 (%_ASM_AX)
-	mov %r10, VCPU_R10(%_ASM_AX)
-	mov %r11, VCPU_R11(%_ASM_AX)
-	mov %r12, VCPU_R12(%_ASM_AX)
-	mov %r13, VCPU_R13(%_ASM_AX)
-	mov %r14, VCPU_R14(%_ASM_AX)
-	mov %r15, VCPU_R15(%_ASM_AX)
+	mov %r8,  VCPU_R8 (%rax)
+	mov %r9,  VCPU_R9 (%rax)
+	mov %r10, VCPU_R10(%rax)
+	mov %r11, VCPU_R11(%rax)
+	mov %r12, VCPU_R12(%rax)
+	mov %r13, VCPU_R13(%rax)
+	mov %r14, VCPU_R14(%rax)
+	mov %r15, VCPU_R15(%rax)
 #endif
 
 	/*
diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
index 3a6461694fc2..9273709e4800 100644
--- a/arch/x86/kvm/vmx/vmenter.S
+++ b/arch/x86/kvm/vmx/vmenter.S
@@ -142,14 +142,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
 	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
 	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
 #ifdef CONFIG_X86_64
-	mov VCPU_R8 (%_ASM_AX),  %r8
-	mov VCPU_R9 (%_ASM_AX),  %r9
-	mov VCPU_R10(%_ASM_AX), %r10
-	mov VCPU_R11(%_ASM_AX), %r11
-	mov VCPU_R12(%_ASM_AX), %r12
-	mov VCPU_R13(%_ASM_AX), %r13
-	mov VCPU_R14(%_ASM_AX), %r14
-	mov VCPU_R15(%_ASM_AX), %r15
+	mov VCPU_R8 (%rax),  %r8
+	mov VCPU_R9 (%rax),  %r9
+	mov VCPU_R10(%rax), %r10
+	mov VCPU_R11(%rax), %r11
+	mov VCPU_R12(%rax), %r12
+	mov VCPU_R13(%rax), %r13
+	mov VCPU_R14(%rax), %r14
+	mov VCPU_R15(%rax), %r15
 #endif
 	/* Load guest RAX.  This kills the @regs pointer! */
 	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
@@ -175,14 +175,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
 	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
 	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
 #ifdef CONFIG_X86_64
-	mov %r8,  VCPU_R8 (%_ASM_AX)
-	mov %r9,  VCPU_R9 (%_ASM_AX)
-	mov %r10, VCPU_R10(%_ASM_AX)
-	mov %r11, VCPU_R11(%_ASM_AX)
-	mov %r12, VCPU_R12(%_ASM_AX)
-	mov %r13, VCPU_R13(%_ASM_AX)
-	mov %r14, VCPU_R14(%_ASM_AX)
-	mov %r15, VCPU_R15(%_ASM_AX)
+	mov %r8,  VCPU_R8 (%rax)
+	mov %r9,  VCPU_R9 (%rax)
+	mov %r10, VCPU_R10(%rax)
+	mov %r11, VCPU_R11(%rax)
+	mov %r12, VCPU_R12(%rax)
+	mov %r13, VCPU_R13(%rax)
+	mov %r14, VCPU_R14(%rax)
+	mov %r15, VCPU_R15(%rax)
 #endif
 
 	/* Clear RAX to indicate VM-Exit (as opposed to VM-Fail). */
-- 
2.31.1


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] KVM: SVM/VMX: Use %rax instead of %__ASM_AX within CONFIG_X86_64
  2021-05-12 11:21 [PATCH] KVM: SVM/VMX: Use %rax instead of %__ASM_AX within CONFIG_X86_64 Uros Bizjak
@ 2021-05-12 11:58 ` Paolo Bonzini
  2021-05-12 15:27   ` Sean Christopherson
  0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2021-05-12 11:58 UTC (permalink / raw)
  To: Uros Bizjak, kvm, linux-kernel

On 12/05/21 13:21, Uros Bizjak wrote:
> There is no need to use %__ASM_AX within CONFIG_X86_64. The macro
> will always expand to %rax.
> 
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> ---
>   arch/x86/kvm/svm/vmenter.S | 44 +++++++++++++++++++-------------------
>   arch/x86/kvm/vmx/vmenter.S | 32 +++++++++++++--------------
>   2 files changed, 38 insertions(+), 38 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
> index 4fa17df123cd..844b558bb021 100644
> --- a/arch/x86/kvm/svm/vmenter.S
> +++ b/arch/x86/kvm/svm/vmenter.S
> @@ -64,14 +64,14 @@ SYM_FUNC_START(__svm_vcpu_run)
>   	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
>   	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
>   #ifdef CONFIG_X86_64
> -	mov VCPU_R8 (%_ASM_AX),  %r8
> -	mov VCPU_R9 (%_ASM_AX),  %r9
> -	mov VCPU_R10(%_ASM_AX), %r10
> -	mov VCPU_R11(%_ASM_AX), %r11
> -	mov VCPU_R12(%_ASM_AX), %r12
> -	mov VCPU_R13(%_ASM_AX), %r13
> -	mov VCPU_R14(%_ASM_AX), %r14
> -	mov VCPU_R15(%_ASM_AX), %r15
> +	mov VCPU_R8 (%rax),  %r8
> +	mov VCPU_R9 (%rax),  %r9
> +	mov VCPU_R10(%rax), %r10
> +	mov VCPU_R11(%rax), %r11
> +	mov VCPU_R12(%rax), %r12
> +	mov VCPU_R13(%rax), %r13
> +	mov VCPU_R14(%rax), %r14
> +	mov VCPU_R15(%rax), %r15
>   #endif
>   
>   	/* "POP" @vmcb to RAX. */
> @@ -93,21 +93,21 @@ SYM_FUNC_START(__svm_vcpu_run)
>   	pop %_ASM_AX
>   
>   	/* Save all guest registers.  */
> -	mov %_ASM_CX,   VCPU_RCX(%_ASM_AX)
> -	mov %_ASM_DX,   VCPU_RDX(%_ASM_AX)
> -	mov %_ASM_BX,   VCPU_RBX(%_ASM_AX)
> -	mov %_ASM_BP,   VCPU_RBP(%_ASM_AX)
> -	mov %_ASM_SI,   VCPU_RSI(%_ASM_AX)
> -	mov %_ASM_DI,   VCPU_RDI(%_ASM_AX)
> +	mov %_ASM_CX, VCPU_RCX(%_ASM_AX)
> +	mov %_ASM_DX, VCPU_RDX(%_ASM_AX)
> +	mov %_ASM_BX, VCPU_RBX(%_ASM_AX)
> +	mov %_ASM_BP, VCPU_RBP(%_ASM_AX)
> +	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
> +	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
>   #ifdef CONFIG_X86_64
> -	mov %r8,  VCPU_R8 (%_ASM_AX)
> -	mov %r9,  VCPU_R9 (%_ASM_AX)
> -	mov %r10, VCPU_R10(%_ASM_AX)
> -	mov %r11, VCPU_R11(%_ASM_AX)
> -	mov %r12, VCPU_R12(%_ASM_AX)
> -	mov %r13, VCPU_R13(%_ASM_AX)
> -	mov %r14, VCPU_R14(%_ASM_AX)
> -	mov %r15, VCPU_R15(%_ASM_AX)
> +	mov %r8,  VCPU_R8 (%rax)
> +	mov %r9,  VCPU_R9 (%rax)
> +	mov %r10, VCPU_R10(%rax)
> +	mov %r11, VCPU_R11(%rax)
> +	mov %r12, VCPU_R12(%rax)
> +	mov %r13, VCPU_R13(%rax)
> +	mov %r14, VCPU_R14(%rax)
> +	mov %r15, VCPU_R15(%rax)
>   #endif
>   
>   	/*
> diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
> index 3a6461694fc2..9273709e4800 100644
> --- a/arch/x86/kvm/vmx/vmenter.S
> +++ b/arch/x86/kvm/vmx/vmenter.S
> @@ -142,14 +142,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
>   	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
>   	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
>   #ifdef CONFIG_X86_64
> -	mov VCPU_R8 (%_ASM_AX),  %r8
> -	mov VCPU_R9 (%_ASM_AX),  %r9
> -	mov VCPU_R10(%_ASM_AX), %r10
> -	mov VCPU_R11(%_ASM_AX), %r11
> -	mov VCPU_R12(%_ASM_AX), %r12
> -	mov VCPU_R13(%_ASM_AX), %r13
> -	mov VCPU_R14(%_ASM_AX), %r14
> -	mov VCPU_R15(%_ASM_AX), %r15
> +	mov VCPU_R8 (%rax),  %r8
> +	mov VCPU_R9 (%rax),  %r9
> +	mov VCPU_R10(%rax), %r10
> +	mov VCPU_R11(%rax), %r11
> +	mov VCPU_R12(%rax), %r12
> +	mov VCPU_R13(%rax), %r13
> +	mov VCPU_R14(%rax), %r14
> +	mov VCPU_R15(%rax), %r15
>   #endif
>   	/* Load guest RAX.  This kills the @regs pointer! */
>   	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
> @@ -175,14 +175,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
>   	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
>   	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
>   #ifdef CONFIG_X86_64
> -	mov %r8,  VCPU_R8 (%_ASM_AX)
> -	mov %r9,  VCPU_R9 (%_ASM_AX)
> -	mov %r10, VCPU_R10(%_ASM_AX)
> -	mov %r11, VCPU_R11(%_ASM_AX)
> -	mov %r12, VCPU_R12(%_ASM_AX)
> -	mov %r13, VCPU_R13(%_ASM_AX)
> -	mov %r14, VCPU_R14(%_ASM_AX)
> -	mov %r15, VCPU_R15(%_ASM_AX)
> +	mov %r8,  VCPU_R8 (%rax)
> +	mov %r9,  VCPU_R9 (%rax)
> +	mov %r10, VCPU_R10(%rax)
> +	mov %r11, VCPU_R11(%rax)
> +	mov %r12, VCPU_R12(%rax)
> +	mov %r13, VCPU_R13(%rax)
> +	mov %r14, VCPU_R14(%rax)
> +	mov %r15, VCPU_R15(%rax)
>   #endif
>   
>   	/* Clear RAX to indicate VM-Exit (as opposed to VM-Fail). */
> 

It looks a bit weird either way (either the address is different within 
the #ifdef, or the address is different from the destinatino), so I lean 
more towards avoiding churn.

Paolo


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] KVM: SVM/VMX: Use %rax instead of %__ASM_AX within CONFIG_X86_64
  2021-05-12 11:58 ` Paolo Bonzini
@ 2021-05-12 15:27   ` Sean Christopherson
  0 siblings, 0 replies; 3+ messages in thread
From: Sean Christopherson @ 2021-05-12 15:27 UTC (permalink / raw)
  To: Paolo Bonzini; +Cc: Uros Bizjak, kvm, linux-kernel

On Wed, May 12, 2021, Paolo Bonzini wrote:
> On 12/05/21 13:21, Uros Bizjak wrote:
> > There is no need to use %__ASM_AX within CONFIG_X86_64. The macro
> > will always expand to %rax.
> > diff --git a/arch/x86/kvm/vmx/vmenter.S b/arch/x86/kvm/vmx/vmenter.S
> > index 3a6461694fc2..9273709e4800 100644
> > --- a/arch/x86/kvm/vmx/vmenter.S
> > +++ b/arch/x86/kvm/vmx/vmenter.S
> > @@ -142,14 +142,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
> >   	mov VCPU_RSI(%_ASM_AX), %_ASM_SI
> >   	mov VCPU_RDI(%_ASM_AX), %_ASM_DI
> >   #ifdef CONFIG_X86_64
> > -	mov VCPU_R8 (%_ASM_AX),  %r8
> > -	mov VCPU_R9 (%_ASM_AX),  %r9
> > -	mov VCPU_R10(%_ASM_AX), %r10
> > -	mov VCPU_R11(%_ASM_AX), %r11
> > -	mov VCPU_R12(%_ASM_AX), %r12
> > -	mov VCPU_R13(%_ASM_AX), %r13
> > -	mov VCPU_R14(%_ASM_AX), %r14
> > -	mov VCPU_R15(%_ASM_AX), %r15
> > +	mov VCPU_R8 (%rax),  %r8
> > +	mov VCPU_R9 (%rax),  %r9
> > +	mov VCPU_R10(%rax), %r10
> > +	mov VCPU_R11(%rax), %r11
> > +	mov VCPU_R12(%rax), %r12
> > +	mov VCPU_R13(%rax), %r13
> > +	mov VCPU_R14(%rax), %r14
> > +	mov VCPU_R15(%rax), %r15
> >   #endif
> >   	/* Load guest RAX.  This kills the @regs pointer! */
> >   	mov VCPU_RAX(%_ASM_AX), %_ASM_AX
> > @@ -175,14 +175,14 @@ SYM_FUNC_START(__vmx_vcpu_run)
> >   	mov %_ASM_SI, VCPU_RSI(%_ASM_AX)
> >   	mov %_ASM_DI, VCPU_RDI(%_ASM_AX)
> >   #ifdef CONFIG_X86_64
> > -	mov %r8,  VCPU_R8 (%_ASM_AX)
> > -	mov %r9,  VCPU_R9 (%_ASM_AX)
> > -	mov %r10, VCPU_R10(%_ASM_AX)
> > -	mov %r11, VCPU_R11(%_ASM_AX)
> > -	mov %r12, VCPU_R12(%_ASM_AX)
> > -	mov %r13, VCPU_R13(%_ASM_AX)
> > -	mov %r14, VCPU_R14(%_ASM_AX)
> > -	mov %r15, VCPU_R15(%_ASM_AX)
> > +	mov %r8,  VCPU_R8 (%rax)
> > +	mov %r9,  VCPU_R9 (%rax)
> > +	mov %r10, VCPU_R10(%rax)
> > +	mov %r11, VCPU_R11(%rax)
> > +	mov %r12, VCPU_R12(%rax)
> > +	mov %r13, VCPU_R13(%rax)
> > +	mov %r14, VCPU_R14(%rax)
> > +	mov %r15, VCPU_R15(%rax)
> >   #endif
> >   	/* Clear RAX to indicate VM-Exit (as opposed to VM-Fail). */
> > 
> 
> It looks a bit weird either way (either the address is different within the
> #ifdef, or the address is different from the destinatino), so I lean more
> towards avoiding churn.

Even though it's unnecessary, I prefer %_ASM_AX since it provides a consistent
flow across the 64-bit-only boundary.

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2021-05-12 16:02 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-05-12 11:21 [PATCH] KVM: SVM/VMX: Use %rax instead of %__ASM_AX within CONFIG_X86_64 Uros Bizjak
2021-05-12 11:58 ` Paolo Bonzini
2021-05-12 15:27   ` Sean Christopherson

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