Re: [Xen-devel] [PATCH v7 4/5] xen/arm: add SGI handling for GICv3

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Fri, 2014-07-11 at 15:12 +0100, Julien Grall wrote:
> On 07/11/2014 03:08 PM, Ian Campbell wrote:
> > On Fri, 2014-07-11 at 14:43 +0100, Julien Grall wrote:
> >>> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
> >>> index 3647497..e15d509 100644
> >>> --- a/xen/arch/arm/vgic.c
> >>> +++ b/xen/arch/arm/vgic.c
> >>> @@ -343,6 +343,13 @@ out:
> >>>          smp_send_event_check_mask(cpumask_of(v->processor));
> >>>  }
> >>>  
> >>> +int vgic_emulate(struct cpu_user_regs *regs, union hsr hsr)
> >>> +{
> >>> +    struct vcpu *v = current;
> >>> +
> >>> +    return v->domain->arch.vgic.handler->emulate_sysreg(regs, hsr);
> >>> +}
> >>> +
> >>
> >> You didn't implement emulate_sysreg for vgic-v2. If the GICv3 is
> >> misprogrammed, Xen will segfault...
> > 
> > Which isn't all that different to the BUG_ON(!->emulate_sysreg) which I
> > would be in favour of, since misprogramming the GIC is a coding error...
> 
> I expect this function to be called often (everytime the guest is
> sending an SGI), so adding BUG_ON(!->emulate_sysreg) will "slow down"
> the emulation.

Then use ASSERT which are in debug builds only.

Ian.


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel