Re: [Qemu-devel] [PATCH] migration: fix analyze-migration.py script with radix table

[David Gibson <david@gibson.dropbear.id.au>]

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On Tue, Dec 05, 2017 at 12:44:40PM +0000, Dr. David Alan Gilbert wrote:
> * Laurent Vivier (lvivier@redhat.com) wrote:
> > Since commit 3a38429748 ("Add a "no HPT" encoding to HTAB migration stream")
> > the HTAB migration stream contains a header set to "-1", meaning there
> > is no HPT. Teach analyze-migration.py to ignore the section in this case.
> > 
> > Without this fix, the script fails with a dump from a POWER9 guest:
> > 
> > Traceback (most recent call last):
> >   File "./qemu/scripts/analyze-migration.py", line 602, in <module>
> >     dump.read(dump_memory = args.memory)
> >   File "./qemu/scripts/analyze-migration.py", line 539, in read
> >     section.read()
> >   File "./qemu/scripts/analyze-migration.py", line 250, in read
> >     self.file.readvar(n_valid * self.HASH_PTE_SIZE_64)
> >   File "./qemu/scripts/analyze-migration.py", line 64, in readvar
> >     raise Exception("Unexpected end of %s at 0x%x" % (self.filename, self.file.tell()))
> > Exception: Unexpected end of migrate.dump at 0x1d4763ba
> > 
> > Fixes: 3a38429748 ("Add a "no HPT" encoding to HTAB migration stream")
> > Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> 
> Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Should I queue this (for 2.12), or do you want to take it via the
migration tree?

> 
> > ---
> >  scripts/analyze-migration.py | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/scripts/analyze-migration.py b/scripts/analyze-migration.py
> > index 14553876a2..88ff4adb30 100755
> > --- a/scripts/analyze-migration.py
> > +++ b/scripts/analyze-migration.py
> > @@ -234,6 +234,10 @@ class HTABSection(object):
> >  
> >          header = self.file.read32()
> >  
> > +        if (header == -1):
> > +            # "no HPT" encoding
> > +            return
> > +
> >          if (header > 0):
> >              # First section, just the hash shift
> >              return

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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