-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Il 30/04/2013 04:23, David Gibson ha scritto: >>> I think this is a different problem. Basically the question is >>> "what happens if a MemoryRegion 'disappears' while an >>> AddressSpace is still referring to it", and the answer right >>> now is "badness". >> >> Well.. no. The same problem may well exist for AddressSpace >> objects, but in this case it's for the VFIO private >> per-address-space object.
Well, once we clarify the lifetime of AddressSpaces, we can clarify the lifetime of the VFIO private object. >>> We should look at generic fixes before dropping hooks in the >>> code. At the very least an "assert(mr->parent == NULL);" is >>> missing in memory_region_destroy. >> >> Well, sure that's probably also a good idea. But the whole point >> here is you're insisting that the MemoryRegion code doesn't know >> about the vfio private data, even as an opaque handle, and so >> there's no possible assert we can put there to check it has been >> destroyed. > > Oh, yes, forgot to ask. I'm still unclear on what the conceptual > difference is supposed to between a MemoryRegion and an > AddressSpace. AFAICT AddressSpace seems to be roughly just a > wrapper on a MemoryRegion that gives it some more features. Yes, an AddressSpace is a wrapper for a MemoryRegion that has a NULL - ->parent, with two extra features: - - QEMU computes the "flat" view of the MemoryRegion and a compressed radix tree representation of that view - - MemoryListeners can ask to be called only for some AddressSpaces Paolo -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJRf3MEAAoJEBvWZb6bTYbyRtEQAImxNNRh39bektv28FJ58hre XrEbck6PZZmJr2xARUrqdri4U8Dw/vXSJOyVWEfQWBvswDBImb6ATO3CcGGYztxS zxmget+Uobbd6ibtKU88JZP0w1WJV7Cn0oj//ylvp+I1DzCJpLRDZJLYMKMns28F KLvA9OTLXlExqEx3/qLc38rIPJ/OJmMqMgCmwNT8ba03wmvO9lSNjHsqi4Htg8Ml AnC29dfiLoNE4Zw+E/N9X7AeNaDvG2GJ52G9suJcd8fgkirEzOfwTqirxeEEGeDw oX7PX02yUuPMo5p6BeocqKFS5qgU9oMwSwSYSuy+0uMcoeBhLaVYXy1pRZDvIWVz b6hHSNc3TsgNlmi2hwYjJG/4ARngXvS1llNCvfNpuENAq3H2zH0DjpW5IHOrt9cv 97FPeWKzka2MqLUkdziGKyno2Tlgq10lfqF4TS85PhXgP66A4gtMo1XeZosCIYjX rGNoQuSnau/938H4Nkt3TAIGQZNypycPeIBXhDNQjFhKXrlLbQjdI5FCjs+3De83 AjEB4OqPEWJ2xeP9HefrEajLQB0T/MSGvoExZKBnFfFyqSv8a7MPZElSnLL6fJ4T /fj/ow3gBbDz4SnNg80FxxbZI8UOvxz3mUcCK8ogQiRBkYdp8M6lmA1rvO1FTafT f1eyeutVKUrfyanZfHy8 =yOML -----END PGP SIGNATURE-----
