Re: [Xen-devel] VM save/restore

[Junjie Wei <junjie.wei@xxxxxxxxxx>]

On 08/18/2012 02:38 AM, Keir Fraser wrote:
> > It was caused by a hard-coded limit in tools/libxc/xc_domain_save.c:
> >
> > if ( info.max_vcpu_id >= 64 )
> > {
> >        ERROR("Too many VCPUS in guest!");
> >        goto out;
> > }
> >
> > And also in tools/libxc/xc_domain_restore.c:
> >
> > case XC_SAVE_ID_VCPU_INFO:
> >        buf->new_ctxt_format = 1;
> >        if ( RDEXACT(fd, &buf->max_vcpu_id, sizeof(buf->max_vcpu_id)) ||
> >            buf->max_vcpu_id >= 64 || RDEXACT(fd, &buf->vcpumap,
> >                                              sizeof(uint64_t)) ) {
> >            PERROR("Error when reading max_vcpu_id");
> >            return -1;
> >        }
> >
> > The code above is in both xen-4.1.2 and xen-unstable.
> >
> > I think if a VM can be successfully started, then save/restore should
> > also work. So I made a patch and did some testing.
> The check for 64 VCPUs is to cover the fact we only save/restore a 64-bit
> vcpumap. That would need fixing too surely, ot CPUs > 64 would be offline
> after restore I would imagine.
>
> And what is a PVM guest?
>
>   -- Keir
Paravirtualization / modified kernel. Am I using the wrong term "PVM"?

Thanks,
Junjie


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