KVM: x86: Refactor kvm_vcpu_do_singlestep() to remove out param

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.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 786d2f88fdf508760854b03380448f2af979306a..e6063f20259e96234d06c2bec4fdda27cd0b8f34 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6474,7 +6474,7 @@ 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;
 
@@ -6483,10 +6483,10 @@ 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)
@@ -6507,7 +6507,7 @@ 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);
@@ -6720,7 +6720,7 @@ restart:
                    exception_type(ctxt->exception.vector) == EXCPT_TRAP) {
                        kvm_rip_write(vcpu, ctxt->eip);
                        if (r == EMULATE_DONE && ctxt->tf)
-                               kvm_vcpu_do_singlestep(vcpu, &r);
+                               r = kvm_vcpu_do_singlestep(vcpu);
                        __kvm_set_rflags(vcpu, ctxt->eflags);
                }