Re: [Xen-devel] [PATCH] xen: arm: vtimer fixes for arm64

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 6 Dec 2013, Ian Campbell wrote:
> On Fri, 2013-12-06 at 17:38 +0000, Stefano Stabellini wrote:
> > On Thu, 5 Dec 2013, Ian Campbell wrote:
> > > @@ -227,12 +242,18 @@ static int vtimer_emulate_sysreg(struct 
> > > cpu_user_regs *regs, union hsr hsr)
> > >      {
> > >      case CNTP_CTL_EL0:
> > >          vtimer_cntp_ctl(regs, &r, sysreg.read);
> > > -        *x = r;
> > > +        if ( sysreg.read )
> > > +            *x = r;
> > >          return 1;
> > >      case CNTP_TVAL_EL0:
> > >          vtimer_cntp_tval(regs, &r, sysreg.read);
> > > -        *x = r;
> > > +        if ( sysreg.read )
> > > +            *x = r;
> > >          return 1;
> > 
> > Are you sure that sysreg.read == 1 means write?
> 
> On the contrary, it means read.
> 
> Here x points to the guest reg that is the target of the read, and r is
> the new value which the emulation has produced.
> 
> So *x = r is implementing a read from the guest's PoV.

Ops, that's right.

Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>

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