linux-kernel - Re: [PATCH] KVM: svm: support single stepping over emulated instructions

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Message-ID: <1586416935.1003490.1501738219700.JavaMail.zimbra@redhat.com>
Date:   Thu, 3 Aug 2017 01:30:19 -0400 (EDT)
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Radim Krčmář <rkrcmar@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org, me@...ehuey.com
Subject: Re: [PATCH] KVM: svm: support single stepping over emulated
 instructions


> We already have b742c1e6e79d ("KVM: SVM: handle singlestep exception
> when skipping emulated instructions"), so the only applicable part of
> this patch is

Doh. :)

> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 0e846f0cb83b..931ba449456e 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -5548,6 +5548,7 @@ static void kvm_vcpu_do_singlestep(struct kvm_vcpu
> > *vcpu, int *r)
> >  		 */
> >  		vcpu->arch.dr6 &= ~15;
> >  		vcpu->arch.dr6 |= DR6_BS | DR6_RTM;
> > +		kvm_update_dr6(vcpu);
> >  		kvm_queue_exception(vcpu, DB_VECTOR);
> >  	}
> >  }
> 
> which makes sense.  And shouldn't we do the same for
> kvm_vcpu_check_breakpoint()?

Yes, will send v2.

Paolo