* Peter Maydell (peter.mayd...@linaro.org) wrote: > On 7 August 2018 at 15:57, Dr. David Alan Gilbert <dgilb...@redhat.com> wrote: > > * Gerd Hoffmann (kra...@redhat.com) wrote: > >> On Fri, Jul 20, 2018 at 10:19:48AM +0200, remy.n...@blade-group.com wrote: > >> > From: "Remy Noel" <remy.n...@blade-group.com> > >> > > >> > When removing a secondary-vga device and then adding it back (or adding > >> > an other one), qemu aborts with: > >> > "RAMBlock "0000:00:02.0/vga.vram" already registered, abort!". > >> > > >> > It is caused by the vram staying registered, preventing vga replugging. > >> > >> David? Does that look ok? > >> > >> This balances the > >> > >> vmstate_register_ram(&s->vram, s->global_vmstate ? NULL : > >> DEVICE(obj)); > >> > >> call in vga_common_init(). I'm wondering whenever the manual cleanup is > >> actually needed in case owner is not NULL? > > > > I can't see anyone who is calling unregister_ram or the functions it > > calls as part of generic device cleanup, so I think it IS needed > > to manually do it. > > > > Which is a bit worrying since we have vastly more register's than > > unregister's. > > Paolo suggested in an email last month that vmstate_unregister_ram() > should simply not exist, because it doesn't actually do anything useful: > https://lists.gnu.org/archive/html/qemu-devel/2018-07/msg01125.html > > (ie it was added in the first place because we'd ended up with > two identically named ramblocks, but that only happened because > a reference-counting bug meant we hadn't deleted the first one > properly before creating the second.) > > So I think that the bug reported in this thread is similar: > the problem is not that we're not calling vmstate_unregister_ram(), > but that when the first instance of secondary-vga is removed > it is not correctly destroying the ramblock.
Ah yes that makes more sense; I remember there was another similar bug where a device screwed up and didn't delete it's RAM causing similar problems. Dave > thanks > -- PMM -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
