Re: [Xen-devel] [PATCH RESEND v5 1/6] xen/arm: Implement hvm save and restore

[Eugene Fedotov <e.fedotov@xxxxxxxxxxx>]

13.11.2013 15:47, Ian Campbell ÐÐÑÐÑ:
> On Wed, 2013-11-13 at 15:50 +0400, Eugene Fedotov wrote:
> > 13.11.2013 14:56, Ian Campbell ÐÐÑÐÑ:
> > > On Wed, 2013-11-13 at 12:00 +0400, Eugene Fedotov wrote:
> > >
> > > > > [...]
> > > > > > +static int vgic_irq_rank_save(struct vgic_rank *ext,
> > > > > > +                               struct vgic_irq_rank *rank)
> > > > > > +{
> > > > > > +    spin_lock(&rank->lock);
> > > > > This is probably wise, but the domain must be paused at this point,
> > > > > right?
> > > > I think this lock can be removed, thanks.
> > > I'd be happy for it to stay as a belt-and-braces/good practice thing.
> > >
> > > > > > +        return -EINVAL;
> > > > > > +    }
> > > > > > +    memcpy(ext->ipriority, rank->ipriority, sizeof(rank->ipriority));
> > > > > > +    /* ITARGETS */
> > > > > > +    if ( sizeof(rank->itargets) != sizeof (ext->itargets) )
> > > > > > +    {
> > > > > > +        dprintk(XENLOG_G_ERR, "hvm_hw_gic: check itargets dumping space\n");
> > > > > > +        return -EINVAL;
> > > > > > +    }
> > > > > > +    memcpy(ext->itargets, rank->itargets, sizeof(rank->itargets));
> > > > > > +    spin_unlock(&rank->lock);
> > > > > > +    return 0;
> > > > > > +}
> > > > > > +
> > > > > > +static int gic_save(struct domain *d, hvm_domain_context_t *h)
> > > > > > +{
> > > > > > +    struct hvm_hw_gic ctxt;
> > > > > > +    struct vcpu *v;
> > > > > > +
> > > > > > +    /* Save the state of GICs */
> > > > > > +    for_each_vcpu( d, v )
> > > > > Where is the GICD state saved then?
> > > > The only GICD structure we save for guest domain is struct
> > > > vgic_irq_rank, it includes: IENABLE, IACTIVE, IPEND,  PENDSGI, ICFG,
> > > > IPRIORITY, ITARGETS registers. We create the same structure inside hvm :
> > > > vgic_rank (that is no guaranteed to be the same as struct vgic_irq_rank)
> > > > and save it calling vgic_irq_rank_save routine below in gic_save.
> > > I can only see one call to vgic_irq_rank_save which is the one to save
> > > PPI state within the vcpu loop. What about the (per-cpu) SGI and
> > > (global) SPIs? I can't see where either of those are saved.
> > 1) For the guest domain vgic.nr_lines was set to 0 (arch_domain
> > structure, see "domain_vgic_init" function in vgic.c):
> > d->arch.vgic.nr_lines = 0; /* We don't need SPIs for the guest */
> > Should we not rely on this, assuming that SPIs will be enabled for guest?
> Aha! I'd forgotten about that. I think we can safely ignore SPIs until
> device passthrough is added. And even then I don't think we would want
> to migrate with an active passthrough device attached.
>
> > 2) Could you point me where is SGI states are situated in arch_vcpu? I
> > thought they are inside those 32 IRQs (namely 0-15 IRQs) that we have
> > already saved, because vgic_irq_rank in arch_vcpu is the context for
> > those 32 IRQs.
> SGIs are "interrupts" 0..15 which PPIs are "interrupts" 16..31, so if
> you are saving the first rank which contains all 32 of those then I
> think you have probably covered them already. I think you just need to
> update the comment(s) to mention SGI as well as PPI.
OK, thanks.

Best regards,
Evgeny.

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