Re: [Xen-devel] how to recognize in libxl that a domU has qemu-xen attached?

[Juergen Gross <jgross@xxxxxxxx>]

On 17/05/18 14:33, Olaf Hering wrote:
> In the other thread about the unsolved migration bugs in qemu-xen it became 
> clear that "xen-save-devices-state" must not only be called for HVM, but for 
> every domU that has qemu-xen attached to it. I wonder how to check for that 
> fact from the migration code. While it can continue to rely on 
> LIBXL_DOMAIN_TYPE_HVM make that call, for  LIBXL_DOMAIN_TYPE_PV it is 
> apparently not that easy. Is libxl__need_xenpv_qemu the API to use for the 
> decision if libxl__qmp_stop/libxl__qmp_save/libxl__qmp_resume have to be 
> called during migration?

libxl__need_xenpv_qemu() is used to determine whether a pv domain needs
a qemu process for at least one backend. To check for the correct qemu
type you need to call libxl__device_model_version_running() and test the
return value being LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN. So you need:

if (libxl__need_xenpv_qemu(gc, d_config) &&
    libxl__device_model_version_running(gc, domid) ==
        LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN)
    libxl__qmp_stop(...);


Juergen

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel