Re: [Qemu-devel] efi var store migration assert (bdrv_co_do_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed.)

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Laszlo Ersek (lersek@redhat.com) wrote:
> On 04/05/16 12:48, Dr. David Alan Gilbert wrote:
> > * Paolo Bonzini (pbonzini@redhat.com) wrote:
> >>
> >>
> >> On 01/04/2016 19:58, Dr. David Alan Gilbert wrote:
> >>> In the continuing journeys of trying to migrate a q35 guest with ovmf,
> >>> I've just hit this assert:
> >>>
> >>> qemu-system-x86_64: /root/git/qemu/block/io.c:1297: bdrv_co_do_pwritev: Assertion `!(bs->open_flags & 0x0800)' failed.
> >>>
> >>> This is just ahead of rc0 - 1458317c8ada834cf39287f6d11a8cb8a37360d6 from yesterday.
> >>
> >> Try this...
> > 
> > Well, migration survives; how do I test if pflash is sane after migration?
> 
> You can run sha1sum before / after. The varstore is expected to change
> only when the UEFI variable servies are exercised. So, if you boot e.g.
> a Linux guest to a login prompt on the source host, checksum the
> varstore, then migrate the guest, then verify the checksum on the target
> host (or, well, shared storage, if you have set it up), it should match.

OK, yes that works; and I also tried using efibootmgr to tweak the timeout,
seeing that the sha changed and then check the sha was correct again after
migration.

Dave

> 
> Thanks
> Laszlo
> 
> > 
> > Dave
> > 
> >> Paolo
> >>
> >> diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c
> >> index c475c2a..e96a7b0 100644
> >> --- a/hw/block/pflash_cfi01.c
> >> +++ b/hw/block/pflash_cfi01.c
> >> @@ -46,6 +46,7 @@
> >>  #include "exec/address-spaces.h"
> >>  #include "qemu/host-utils.h"
> >>  #include "hw/sysbus.h"
> >> +#include "sysemu/sysemu.h"
> >>  
> >>  #define PFLASH_BUG(fmt, ...) \
> >>  do { \
> >> @@ -97,6 +98,7 @@ struct pflash_t {
> >>      MemoryRegion mem;
> >>      char *name;
> >>      void *storage;
> >> +    VMChangeStateEntry *vmstate;
> >>  };
> >>  
> >>  static int pflash_post_load(void *opaque, int version_id);
> >> @@ -944,13 +946,24 @@ MemoryRegion *pflash_cfi01_get_memory(pflash_t *fl)
> >>      return &fl->mem;
> >>  }
> >>  
> >> +static void postload_update_cb(void *opaque, int running, RunState state)
> >> +{
> >> +    pflash_t *pfl = opaque;
> >> +
> >> +    /* This is called after bdrv_invalidate_cache_all.  */
> >> +    qemu_del_vm_change_state_handler(pfl->vmstate);
> >> +    pfl->vmstate = NULL;
> >> +
> >> +    DPRINTF("%s: updating bdrv for %s\n", __func__, pfl->name);
> >> +    pflash_update(pfl, 0, pfl->sector_len * pfl->nb_blocs);
> >> +}
> >> +
> >>  static int pflash_post_load(void *opaque, int version_id)
> >>  {
> >>      pflash_t *pfl = opaque;
> >>  
> >>      if (!pfl->ro) {
> >> -        DPRINTF("%s: updating bdrv for %s\n", __func__, pfl->name);
> >> -        pflash_update(pfl, 0, pfl->sector_len * pfl->nb_blocs);
> >> +        pfl->vmstate = qemu_add_vm_change_state_handler(postload_update_cb, pfl);
> >>      }
> >>      return 0;
> >>  }
> > --
> > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK