Il 23/08/2014 12:19, Laszlo Ersek ha scritto: > Libvirt is growing support for x86_64 OVMF guests: > > http://www.redhat.com/archives/libvir-list/2014-August/msg01045.html > > An important feature of such guests is the persistent store for > non-volatile UEFI variables. This is implemented with if=pflash drives. > The referenced libvirt patchset sets up the varstore files for > single-host use. > > Wrt. migration, two choices have been considered: > (a) full-blown live storage migration for the drives backing pflash > devices, > (b) vs. a shortcut that exploits the special nature of pflash drives > (namely, their minuscule size, and a RAMBlock that keeps the full > contents of each pflash drive visible to the guest, and is > up-to-date, at all times.) > > Patch 1/2 is a trivial cleanup (some DPRINTF() calls in pflash_cfi01 > have bit-rotted). Patch 2/2 seeks to implement choice (b), which is what > the libvirt patchset relies on for migration. > > Thanks, > Laszlo > > Laszlo Ersek (2): > pflash_cfi01: fixup stale DPRINTF() calls > pflash_cfi01: write flash contents to bdrv on incoming migration > > hw/block/pflash_cfi01.c | 18 ++++++++++++++++-- > 1 file changed, 16 insertions(+), 2 deletions(-) >
Reviewed-by: Paolo Bonzini <pbonz...@redhat.com> Alexey/David, I think hw/nvram/spapr_nvram.c should do the same. It doesn't have a vmstate, but you can probably use qemu_add_vm_change_state_handler to the same effect. Paolo