Re: [PATCH RFC XEN v1 06/14] xen: arm: Add some basic platform info to save header

[Ian Campbell <ian.campbell@citrix.com>]

On Tue, 2015-12-15 at 18:37 +0000, Stefano Stabellini wrote:
> On Wed, 9 Dec 2015, Ian Campbell wrote:
> > These correspond to the content of struct xen_arch_domainconfig.
> > 
> > On restore various things are checked, mostly to ensure they match the
> > hardcoded things of the restoring Xen.
> > 
> > Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> > ---
> >  xen/arch/arm/save.c                    | 44
> > ++++++++++++++++++++++++++++++++++
> >  xen/include/public/arch-arm/hvm/save.h |  6 +++++
> >  2 files changed, 50 insertions(+)
> > 
> > diff --git a/xen/arch/arm/save.c b/xen/arch/arm/save.c
> > index 6a1934b..7b34782 100644
> > --- a/xen/arch/arm/save.c
> > +++ b/xen/arch/arm/save.c
> > @@ -21,6 +21,17 @@
> >  
> >  void arch_hvm_save(struct domain *d, struct hvm_save_header *hdr)
> >  {
> > +    switch ( d->arch.vgic.version )
> > +    {
> > +    case GIC_V2: hdr->gic_version = XEN_DOMCTL_CONFIG_GIC_V2; break;
> > +    case GIC_V3: hdr->gic_version = XEN_DOMCTL_CONFIG_GIC_V3; break;
> > +    default: BUG();
> > +    }
> > +
> > +    hdr->nr_spis = d->arch.vgic.nr_spis;
> > +    hdr->clock_frequency = cpu_khz;
> > +
> > +    hdr->evtchn_irq = GUEST_EVTCHN_PPI;
> >  }
> >  
> >  int arch_hvm_load(struct domain *d, struct hvm_save_header *hdr)
> > @@ -39,6 +50,39 @@ int arch_hvm_load(struct domain *d, struct
> > hvm_save_header *hdr)
> >          return -1;
> >      }
> >  
> > +    switch ( hdr->gic_version )
> > +    {
> > +    case XEN_DOMCTL_CONFIG_GIC_V2: d->arch.vgic.version = GIC_V2;
> > break;
> > +    case XEN_DOMCTL_CONFIG_GIC_V3: d->arch.vgic.version = GIC_V3;
> > break;
> > +    default:
> > +        printk(XENLOG_G_ERR "HVM%d restore: unsupported gic version
> > %u\n",
> > +               d->domain_id, hdr->gic_version);
> > +        return -1;
> > +    }
> > +
> > +    if ( hdr->nr_spis )
> > +    {
> > +        printk(XENLOG_G_ERR "HVM%d restore: cannot support nr_spis !=
> > 0, %u\n",
> > +               d->domain_id, hdr->nr_spis);
> > +        return -1;
> > +    }
> > +
> > +    if ( hdr->clock_frequency != cpu_khz )
> > +    {
> > +        printk(XENLOG_G_ERR
> > +            "HVM%d restore: unsupported guest clock %"PRId32"kHz on
> > host @ %ldkHz\n",
> > +            d->domain_id, hdr->clock_frequency, cpu_khz);
> > +        return -1;
> > +    }
> > +
> > +    if ( hdr->evtchn_irq != GUEST_EVTCHN_PPI )
> > +    {
> > +        printk(XENLOG_G_ERR
> > +            "HVM%d restore: unsupported guest evtchn IRQ%u host uses
> > IRQ%u\n",
> > +            d->domain_id, hdr->evtchn_irq, GUEST_EVTCHN_PPI);
> > +        return -1;
> > +    }
> > +
> >      return 0;
> >  }
> >  
> > diff --git a/xen/include/public/arch-arm/hvm/save.h
> > b/xen/include/public/arch-arm/hvm/save.h
> > index 5f4de94..6f1be37 100644
> > --- a/xen/include/public/arch-arm/hvm/save.h
> > +++ b/xen/include/public/arch-arm/hvm/save.h
> > @@ -34,6 +34,12 @@ struct hvm_save_header
> >      uint32_t magic;             /* Must be HVM_FILE_MAGIC */
> >      uint32_t version;           /* File format version */
> >      uint64_t changeset;         /* Version of Xen that saved this file
> > */
> > +
> > +    uint8_t  gic_version;       /* XEN_DOMCTL_CONFIG_GIC_v* (_NOT_
> > _NATIVE) */
> > +    uint32_t nr_spis;           /* Currently must be 0 */
> > +    uint32_t clock_frequency;   /* kHz */
> > +
> > +    uint32_t evtchn_irq;
> 
> I would prefer if you added these in the previous patch, or maybe
> better, you introduced HVM_FILE_VERSION only with the last patch.
> Otherwise theoretically you would have to bump HVM_FILE_VERSION with
> this patch.

I'm not terribly concerned with save file versioning in the midst of the
series which implements save/restore, it's ludicrous to suggest we might be
required to support save/restore with this series half applied, but I'll
fold it in anyway.

> The rest looks good.

Thanks.
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