Re: [Xen-devel] [PATCH v2 2/3] libxl: update vcpus bitmap in retrieved guest config

[Anthony PERARD <anthony.perard@xxxxxxxxxx>]

On Tue, Jun 14, 2016 at 11:58:58AM +0100, Anthony PERARD wrote:
> On Tue, Jun 14, 2016 at 11:50:12AM +0100, Wei Liu wrote:
> > On Tue, Jun 14, 2016 at 11:47:57AM +0100, Anthony PERARD wrote:
> > [...]
> > > > > > +
> > > > > >  int libxl_retrieve_domain_configuration(libxl_ctx *ctx, uint32_t 
> > > > > > domid,
> > > > > >                                          libxl_domain_config 
> > > > > > *d_config)
> > > > > >  {
> > > > > > @@ -7270,6 +7317,46 @@ int 
> > > > > > libxl_retrieve_domain_configuration(libxl_ctx *ctx, uint32_t domid,
> > > > > >          libxl_dominfo_dispose(&info);
> > > > > >      }
> > > > > >  
> > > > > > +    /* VCPUs */
> > > > > > +    {
> > > > > > +        libxl_bitmap *map = &d_config->b_info.avail_vcpus;
> > > > > > +        unsigned int max_vcpus = d_config->b_info.max_vcpus;
> > > > > > +
> > > > > > +        libxl_bitmap_dispose(map);
> > > > > > +        libxl_bitmap_init(map);
> > > > > > +        libxl_bitmap_alloc(CTX, map, max_vcpus);
> > > > > > +        libxl_bitmap_set_none(map);
> > > > > > +
> > > > > > +        switch (d_config->b_info.type) {
> > > > > > +        case LIBXL_DOMAIN_TYPE_HVM:
> > > > > > +            switch (d_config->b_info.device_model_version) {
> > > > > > +            case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN:
> > > > > > +                rc = libxl__update_avail_vcpus_qmp(gc, domid,
> > > > > > +                                                   max_vcpus, map);
> > > > > > +                break;
> > > > > > +            case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL:
> > > > > > +            case LIBXL_DEVICE_MODEL_VERSION_NONE:
> > > > > > +                rc = libxl__update_avail_vcpus_xenstore(gc, domid,
> > > > > > +                                                        max_vcpus, 
> > > > > > map);
> > > > > > +                break;
> > > > > > +            default:
> > > > > > +            abort();
> > > > > 
> > > > > Missing indentation for abort.
> > > > > 
> > > > 
> > > > Will fix.
> > > > 
> > > > > Also, that is where xl abort on migration.
> > > > > 
> > > > 
> > > > Hmm...  This means the device model version is not valid (unknown?).
> > > > 
> > > > Can you paste in your guest config?
> > > 
> > > With all commented line removed:
> > > 
> > > builder = 'hvm'
> > > memory = 500
> > > vcpus = 2
> > > maxvcpus = 6
> > > name = "arch"
> > > vif = [ 'type=ioemu,mac=00:16:3e:XX:XX:XX' ]
> > > disk = [
> > > 'phy:/dev/vg42/guest_arch64,hda,w',
> > >  'file:/root/vm/iso/archlinux-2014.04.01-dual.iso,hdc:cdrom,r',
> > > ]
> > > device_model_args_hvm = [
> > > ]
> > > usbdevice='tablet'
> > > boot="cd"
> > > serial='pty'
> > > sdl = 0
> > > vnc = 1
> > > vnclisten = '0.0.0.0'
> > > vncunused = 1
> > > spice=0
> > > uuid = "XXXX"
> > > 
> > 
> > This means your device model version is LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN
> > so it should be covered by the correct case.
> > 
> > I'm confused.
> 
> If it works for you, I'll properly install Xen with your patch in,
> I may miss something...
> I did:
> LD_LIBRARY_PATH=`pwd` ./xl -vvv migrate arch localhost

I tried again, this time Xen properly installed with your patch series.

sh$ xl create arch.hvm
sh$ xl list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  4000     8     r-----      25.3
arch                                         1   500     2     -b----       5.4
sh$ xl vcpu-set arch 5
sh$ xl list
Name                                        ID   Mem VCPUs      State   Time(s)
Domain-0                                     0  4000     8     r-----      25.8
arch                                         1   500     5     -b----       6.4

# All fine up to here.

sh$ xl migrate arch localhost
Aborted (core dumped)
sh$  xl save arch savefile
Aborted (core dumped)
sh$ xl save arch savefile ~/arch.hvm
Saving to savefile new xl format (info 0x3/0x0/1540)
xc: info: Saving domain 1, type x86 HVM
xc: Frames: 1044482/1044482  100%
xc: End of stream: 0/0    0%

# So there is only one way to migrate or save the guest.

sh$ xl restore savefile
[...]
libxl: error: libxl_dm.c:2187:device_model_spawn_outcome: domain 2 device 
model: spawn failed (rc=-3)
[...]

# So restore still fail with this in QEMU log:
qemu-system-i386: Unknown savevm section or instance 'cpu_common' 2
qemu-system-i386: load of migration failed: Invalid argument

-- 
Anthony PERARD

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