[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [V8 PATCH 7/8] pvh dom0: add check for pvh in vioapic_range
On Mon, 7 Apr 2014 10:28:50 +0100 George Dunlap <george.dunlap@xxxxxxxxxxxxx> wrote: > On 04/07/2014 07:59 AM, Jan Beulich wrote: > >>>> On 05.04.14 at 03:00, <mukesh.rathor@xxxxxxxxxx> wrote: > >> On Tue, 01 Apr 2014 16:09:15 +0100 > >> "Jan Beulich" <JBeulich@xxxxxxxx> wrote: > >> > >>>>>> On 01.04.14 at 16:40, <george.dunlap@xxxxxxxxxxxxx> wrote: > >>>> On 03/24/2014 09:34 AM, Jan Beulich wrote: > >>>>>>>> On 22.03.14 at 02:39, <mukesh.rathor@xxxxxxxxxx> wrote: > >>>>>> --- a/xen/arch/x86/hvm/vioapic.c > >>>>>> +++ b/xen/arch/x86/hvm/vioapic.c > >>>>>> @@ -238,8 +238,13 @@ static int vioapic_write( > >>>>>> > >>>>>> static int vioapic_range(struct vcpu *v, unsigned long addr) > >>>>>> { > >>>>>> - struct hvm_hw_vioapic *vioapic = > >>>>>> domain_vioapic(v->domain); > >>>>>> + struct hvm_hw_vioapic *vioapic; > >>>>>> + > >>>>>> + /* pvh uses event channel callback */ > >>>>>> + if ( is_pvh_vcpu(v) ) > >>>>>> + return 0; > >>>>>> > >>>>>> + vioapic = domain_vioapic(v->domain); > >>>>> I can see why the extra check is needed, but I can't see why you > >>>>> convert the initializer to an assignment: Afaict > >>>>> domain_vioapic() is safe even if d->arch.hvm_domain.vioapic == > >>>>> NULL. > >>>> Or better yet, just make it something like: > >>>> > >>>> return vioapic && ((addr >= [...original range check])) > >>>> > >>>> That way we don't have to have a PVH-specific hook at all. If a > >>>> domain doesn't have a vioapic for any reason, return 0. > >>> No, vioapic isn't going to be NULL for PVH: > >>> > >>> #define domain_vioapic(d) > >>> (&(d)->arch.hvm_domain.vioapic->hvm_hw_vioapic) > >> No, viopaic is NULL for PVH, hence the patch. So, can prob just > >> check for the ptr like George suggests and remove the pvh check. > > Sorry, no - I agree that d->arch.hvm_domain.vioapic is NULL for > > PVH, but that doesn't mean the result of domain_vioapic(d) is too > > (see the quoted #define above). > > I interpreted Mukesh saying "check for the ptr" as, "check > d->arch_hvm.domain.vioapic", not "check domain_vioapic(d)". Correct. Since, vioapic is NULL for PVH, domain_vioapic(d) will result in NULL ptr exception for PVH, so we can't call that macro for PVH. thanks Mukesh _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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