On Wed, Mar 27, 2013 at 12:14:00PM -0500, Anthony Liguori wrote: > Stefan Berger <stef...@linux.vnet.ibm.com> writes: > > > On 03/27/2013 12:12 PM, Joel Schopp wrote: > >> > >>> Yea it's not hard to invent a random format each time we write something > >>> on disk. > >>> > >>> But I think ASN.1 BER will be useful to have in qemu anyway. E.g. it's a > >>> better format for migration than what we have now. Once we have it in > >>> tree re-using it seems cleaner than maintaining some per-TPM thing. > >>> > >> > >> The asn.1 patches that have been posted seem to be getting a cool > >> reception. If people think asn.1 is the way to go some more review > >> comments, acked-bys, reviewed-bys, or signed-off-bys would make that > >> more likely to happen. The patches have gone through several rounds > >> of review and come with a decent set of tests but still haven't been > >> merged. I think they are very mergable. > > > > Let me post another version that makes all the tests in > > test-visitor-serialize pass, including the ones using visit_optional. > > What I struggle with is that we're calling this a "blobstore". Using > BER to store "blobs" seems kind of pointless especially when we're > talking about exactly three blobs. > > I suspect real hardware does something like, flash is N bytes, blob 1 is > a max of X bytes, blob 2 is a max of Y bytes, and blob 3 is (N - X - Y) > bytes. > > Do we really need to do anything more than that? > > Regards, > > Anthony Liguori
Last I looked some metadata was stored per blob, for example I think it has a concept of "number of bytes initialized". So we'll need to serialize that. More can come with time ... > > > > > I also think they are mergeable, but we should discuss a few aspects > > around it. There are standards behind this that we may or may not need > > to implement as such. I am thinking of CER encoding for example that > > imposes restrictions on the size of primitive elements to be less than > > 1000 bytes (section 9.2) and need constructed encoding when bigger. We > > may be able to change this limit to PAGE_SIZE * n with n = ?. There may > > be other aspects. > > > > Stefan
