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

[Laszlo Ersek <lersek@redhat.com>]

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.

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
>