[RESEND,03/13] KVM: x86: Refactor kvm_vcpu_do_singlestep() to remove out param
diff mbox series

Message ID 20190823010709.24879-4-sean.j.christopherson@intel.com
State New
Headers show
Series
  • KVM: x86: Remove emulation_result enums
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Commit Message

Sean Christopherson Aug. 23, 2019, 1:06 a.m. UTC
Return the single-step emulation result directly instead of via an out
param.  Presumably at some point in the past kvm_vcpu_do_singlestep()
could be called with *r==EMULATE_USER_EXIT, but that is no longer the
case, i.e. all callers are happy to overwrite their own return variable.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/x86.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Vitaly Kuznetsov Aug. 23, 2019, 9:32 a.m. UTC | #1
Sean Christopherson <sean.j.christopherson@intel.com> writes:

> Return the single-step emulation result directly instead of via an out
> param.  Presumably at some point in the past kvm_vcpu_do_singlestep()
> could be called with *r==EMULATE_USER_EXIT, but that is no longer the
> case, i.e. all callers are happy to overwrite their own return variable.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>  arch/x86/kvm/x86.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c6de5bc4fa5e..fe847f8eb947 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6377,7 +6377,7 @@ static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,
>  	return dr6;
>  }
>  
> -static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
> +static int kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu)
>  {
>  	struct kvm_run *kvm_run = vcpu->run;
>  
> @@ -6386,10 +6386,10 @@ static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
>  		kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
>  		kvm_run->debug.arch.exception = DB_VECTOR;
>  		kvm_run->exit_reason = KVM_EXIT_DEBUG;
> -		*r = EMULATE_USER_EXIT;
> -	} else {
> -		kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
> +		return EMULATE_USER_EXIT;
>  	}
> +	kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
> +	return EMULATE_DONE;
>  }
>  
>  int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
> @@ -6410,7 +6410,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
>  	 * that sets the TF flag".
>  	 */
>  	if (unlikely(rflags & X86_EFLAGS_TF))
> -		kvm_vcpu_do_singlestep(vcpu, &r);
> +		r = kvm_vcpu_do_singlestep(vcpu);
>  	return r == EMULATE_DONE;
>  }
>  EXPORT_SYMBOL_GPL(kvm_skip_emulated_instruction);
> @@ -6613,7 +6613,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
>  		vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
>  		kvm_rip_write(vcpu, ctxt->eip);
>  		if (r == EMULATE_DONE && ctxt->tf)
> -			kvm_vcpu_do_singlestep(vcpu, &r);
> +			r = kvm_vcpu_do_singlestep(vcpu);
>  		if (!ctxt->have_exception ||
>  		    exception_type(ctxt->exception.vector) == EXCPT_TRAP)
>  			__kvm_set_rflags(vcpu, ctxt->eflags);

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Liran Alon Aug. 23, 2019, 1:05 p.m. UTC | #2
> On 23 Aug 2019, at 4:06, Sean Christopherson <sean.j.christopherson@intel.com> wrote:
> 
> Return the single-step emulation result directly instead of via an out
> param.  Presumably at some point in the past kvm_vcpu_do_singlestep()
> could be called with *r==EMULATE_USER_EXIT, but that is no longer the
> case, i.e. all callers are happy to overwrite their own return variable.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
> arch/x86/kvm/x86.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c6de5bc4fa5e..fe847f8eb947 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6377,7 +6377,7 @@ static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,
> 	return dr6;
> }
> 
> -static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
> +static int kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu)
> {
> 	struct kvm_run *kvm_run = vcpu->run;
> 
> @@ -6386,10 +6386,10 @@ static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
> 		kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
> 		kvm_run->debug.arch.exception = DB_VECTOR;
> 		kvm_run->exit_reason = KVM_EXIT_DEBUG;
> -		*r = EMULATE_USER_EXIT;
> -	} else {
> -		kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
> +		return EMULATE_USER_EXIT;
> 	}
> +	kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
> +	return EMULATE_DONE;
> }
> 
> int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
> @@ -6410,7 +6410,7 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
> 	 * that sets the TF flag".
> 	 */
> 	if (unlikely(rflags & X86_EFLAGS_TF))
> -		kvm_vcpu_do_singlestep(vcpu, &r);
> +		r = kvm_vcpu_do_singlestep(vcpu);
> 	return r == EMULATE_DONE;
> }
> EXPORT_SYMBOL_GPL(kvm_skip_emulated_instruction);
> @@ -6613,7 +6613,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
> 		vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
> 		kvm_rip_write(vcpu, ctxt->eip);
> 		if (r == EMULATE_DONE && ctxt->tf)
> -			kvm_vcpu_do_singlestep(vcpu, &r);
> +			r = kvm_vcpu_do_singlestep(vcpu);
> 		if (!ctxt->have_exception ||
> 		    exception_type(ctxt->exception.vector) == EXCPT_TRAP)
> 			__kvm_set_rflags(vcpu, ctxt->eflags);
> -- 
> 2.22.0
> 

Reviewed-by: Liran Alon <liran.alon@oracle.com>

-Liran

Patch
diff mbox series

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c6de5bc4fa5e..fe847f8eb947 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6377,7 +6377,7 @@  static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7,
 	return dr6;
 }
 
-static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
+static int kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu)
 {
 	struct kvm_run *kvm_run = vcpu->run;
 
@@ -6386,10 +6386,10 @@  static void kvm_vcpu_do_singlestep(struct kvm_vcpu *vcpu, int *r)
 		kvm_run->debug.arch.pc = vcpu->arch.singlestep_rip;
 		kvm_run->debug.arch.exception = DB_VECTOR;
 		kvm_run->exit_reason = KVM_EXIT_DEBUG;
-		*r = EMULATE_USER_EXIT;
-	} else {
-		kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
+		return EMULATE_USER_EXIT;
 	}
+	kvm_queue_exception_p(vcpu, DB_VECTOR, DR6_BS);
+	return EMULATE_DONE;
 }
 
 int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
@@ -6410,7 +6410,7 @@  int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	 * that sets the TF flag".
 	 */
 	if (unlikely(rflags & X86_EFLAGS_TF))
-		kvm_vcpu_do_singlestep(vcpu, &r);
+		r = kvm_vcpu_do_singlestep(vcpu);
 	return r == EMULATE_DONE;
 }
 EXPORT_SYMBOL_GPL(kvm_skip_emulated_instruction);
@@ -6613,7 +6613,7 @@  int x86_emulate_instruction(struct kvm_vcpu *vcpu,
 		vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
 		kvm_rip_write(vcpu, ctxt->eip);
 		if (r == EMULATE_DONE && ctxt->tf)
-			kvm_vcpu_do_singlestep(vcpu, &r);
+			r = kvm_vcpu_do_singlestep(vcpu);
 		if (!ctxt->have_exception ||
 		    exception_type(ctxt->exception.vector) == EXCPT_TRAP)
 			__kvm_set_rflags(vcpu, ctxt->eflags);