Re: [Xen-devel] [PATCH 1/5] arm/vtimer: do not let the guest interact with the physical timer

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 26 Jun 2012, Ian Campbell wrote:
> On Wed, 2012-06-06 at 12:22 +0100, Stefano Stabellini wrote:
> > The guest can read the physical counter but it shouldn't be able to
> > cause interrupts of the physical timer to go to the hypervisor.
> > Trap physical timer reads/writes in vtimer.c instead.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> > ---
> >  xen/arch/arm/time.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
> > index 1587fa2..d5b71d7 100644
> > --- a/xen/arch/arm/time.c
> > +++ b/xen/arch/arm/time.c
> > @@ -160,8 +160,8 @@ void __cpuinit init_timer_interrupt(void)
> >      WRITE_CP64(0, CNTVOFF);     /* No VM-specific offset */
> >      WRITE_CP32(0, CNTKCTL);     /* No user-mode access */
> >  #if USE_HYP_TIMER
> > -    /* Let the VMs read the physical counter and timer so they can tell 
> > time */
> > -    WRITE_CP32(CNTHCTL_PA|CNTHCTL_TA, CNTHCTL);
> > +    /* Do not the VMs program the physical timer, only read the physical 
> > counter */
> 
> "Do not *let* the VMs..." ?

right..


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