Re: [Qemu-devel] [PATCH v2 0/3] Bitmap based CPU enumeration

[Eduardo Habkost]

On Tue, May 19, 2015 at 10:46:03AM +0530, Bharata B Rao wrote:
> On Mon, May 18, 2015 at 04:09:49PM -0300, Eduardo Habkost wrote:
> > On Tue, May 12, 2015 at 11:06:23AM +0530, Bharata B Rao wrote:
> > > This patch changes the way cpu_index is handed out to newly created
> > > CPUs by tracking the allocted CPUs in a bitmap. More information and
> > > the need for this patch is described in patch 2/3 of this series. These
> > > generic changes are needed to support CPU hot plug/unplug on PowerPC.
> > 
> > What about the existing vmstate and savevm calls on cpu_exec_init()?
> > Won't QEMU crash if you destroy the CPU without unregistering the
> > vmstate and savevm handlers?
> 
> There was a patch from Zhu to move the vmstate registration
> code into cpu_common_realizefn
> 
> http://lists.gnu.org/archive/html/qemu-devel/2015-01/msg01550.html
> 
> Also there was also a patch to do unregistration from target CPU's
> unrealizefn for x86.
> 
> https://lists.gnu.org/archive/html/qemu-devel/2015-02/msg02599.html
> 
> On PowerPC Currently I do unregistration in the ppc CPU's unrealizefn.
> 
> But irrespective of how the above patches evolve, does it make
> sense to have unregistration part done in cpu_exec_exit() now as
> part of this patch series ?

It would make sense, but there's no need to do it in this series if we
are already in the process of moving the register/unregister calls
elsewhere.

(But wherever you do the registration calls, you shouldn't need to do
unregistration in arch-specific code if registration is done on generic
code.)

-- 
Eduardo