* [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line
@ 2021-02-26 12:56 Uros Bizjak
2021-02-26 13:46 ` Paolo Bonzini
0 siblings, 1 reply; 2+ messages in thread
From: Uros Bizjak @ 2021-02-26 12:56 UTC (permalink / raw)
To: kvm, linux-kernel; +Cc: Uros Bizjak, Sean Christopherson, Paolo Bonzini
Avoid jump by moving exception fixups out of line.
Cc: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
arch/x86/kvm/svm/vmenter.S | 35 ++++++++++++++++++++---------------
1 file changed, 20 insertions(+), 15 deletions(-)
diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
index 343108bf0f8c..4fa17df123cd 100644
--- a/arch/x86/kvm/svm/vmenter.S
+++ b/arch/x86/kvm/svm/vmenter.S
@@ -80,15 +80,9 @@ SYM_FUNC_START(__svm_vcpu_run)
/* Enter guest mode */
sti
-3: vmrun %_ASM_AX
- jmp 5f
-4: cmpb $0, kvm_rebooting
- jne 5f
- ud2
- _ASM_EXTABLE(3b, 4b)
+1: vmrun %_ASM_AX
-5:
- cli
+2: cli
#ifdef CONFIG_RETPOLINE
/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
@@ -155,6 +149,13 @@ SYM_FUNC_START(__svm_vcpu_run)
#endif
pop %_ASM_BP
ret
+
+3: cmpb $0, kvm_rebooting
+ jne 2b
+ ud2
+
+ _ASM_EXTABLE(1b, 3b)
+
SYM_FUNC_END(__svm_vcpu_run)
/**
@@ -174,18 +175,15 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
#endif
push %_ASM_BX
- /* Enter guest mode */
+ /* Move @vmcb to RAX. */
mov %_ASM_ARG1, %_ASM_AX
+
+ /* Enter guest mode */
sti
1: vmrun %_ASM_AX
- jmp 3f
-2: cmpb $0, kvm_rebooting
- jne 3f
- ud2
- _ASM_EXTABLE(1b, 2b)
-3: cli
+2: cli
#ifdef CONFIG_RETPOLINE
/* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
@@ -205,4 +203,11 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
#endif
pop %_ASM_BP
ret
+
+3: cmpb $0, kvm_rebooting
+ jne 2b
+ ud2
+
+ _ASM_EXTABLE(1b, 3b)
+
SYM_FUNC_END(__svm_sev_es_vcpu_run)
--
2.29.2
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line
2021-02-26 12:56 [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line Uros Bizjak
@ 2021-02-26 13:46 ` Paolo Bonzini
0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2021-02-26 13:46 UTC (permalink / raw)
To: Uros Bizjak, kvm, linux-kernel; +Cc: Sean Christopherson
On 26/02/21 13:56, Uros Bizjak wrote:
> Avoid jump by moving exception fixups out of line.
>
> Cc: Sean Christopherson <seanjc@google.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
> ---
> arch/x86/kvm/svm/vmenter.S | 35 ++++++++++++++++++++---------------
> 1 file changed, 20 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/vmenter.S b/arch/x86/kvm/svm/vmenter.S
> index 343108bf0f8c..4fa17df123cd 100644
> --- a/arch/x86/kvm/svm/vmenter.S
> +++ b/arch/x86/kvm/svm/vmenter.S
> @@ -80,15 +80,9 @@ SYM_FUNC_START(__svm_vcpu_run)
> /* Enter guest mode */
> sti
>
> -3: vmrun %_ASM_AX
> - jmp 5f
> -4: cmpb $0, kvm_rebooting
> - jne 5f
> - ud2
> - _ASM_EXTABLE(3b, 4b)
> +1: vmrun %_ASM_AX
>
> -5:
> - cli
> +2: cli
>
> #ifdef CONFIG_RETPOLINE
> /* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
> @@ -155,6 +149,13 @@ SYM_FUNC_START(__svm_vcpu_run)
> #endif
> pop %_ASM_BP
> ret
> +
> +3: cmpb $0, kvm_rebooting
> + jne 2b
> + ud2
> +
> + _ASM_EXTABLE(1b, 3b)
> +
> SYM_FUNC_END(__svm_vcpu_run)
>
> /**
> @@ -174,18 +175,15 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
> #endif
> push %_ASM_BX
>
> - /* Enter guest mode */
> + /* Move @vmcb to RAX. */
> mov %_ASM_ARG1, %_ASM_AX
> +
> + /* Enter guest mode */
> sti
>
> 1: vmrun %_ASM_AX
> - jmp 3f
> -2: cmpb $0, kvm_rebooting
> - jne 3f
> - ud2
> - _ASM_EXTABLE(1b, 2b)
>
> -3: cli
> +2: cli
>
> #ifdef CONFIG_RETPOLINE
> /* IMPORTANT: Stuff the RSB immediately after VM-Exit, before RET! */
> @@ -205,4 +203,11 @@ SYM_FUNC_START(__svm_sev_es_vcpu_run)
> #endif
> pop %_ASM_BP
> ret
> +
> +3: cmpb $0, kvm_rebooting
> + jne 2b
> + ud2
> +
> + _ASM_EXTABLE(1b, 3b)
> +
> SYM_FUNC_END(__svm_sev_es_vcpu_run)
>
Queued, thanks.
Paolo
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-02-26 12:56 [PATCH] KVM/SVM: Move vmenter.S exception fixups out of line Uros Bizjak
2021-02-26 13:46 ` Paolo Bonzini
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