> On 23 Aug 2019, at 4:06, Sean Christopherson <sean.j.christopherson@xxxxxxxxx> 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@xxxxxxxxx>
> ---
> 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@xxxxxxxxxx>
-Liran
