David Vrabel
2013-Aug-01 11:23 UTC
Re: [PATCH] Xen: Fix retry calls into PRIVCMD_MMAPBATCH*.
On 01/08/13 04:30, Andres Lagar-Cavilla wrote:> -- Resend as I haven''t seen this hit the lists. Maybe some smtp misconfig. Apologies. Also expanded cc -- > > When a foreign mapper attempts to map guest frames that are paged out, > the mapper receives an ENOENT response and will have to try again > while a helper process pages the target frame back in. > > Gating checks on PRIVCMD_MMAPBATCH* ioctl args were preventing retries > of mapping calls.This breaks the auto_translated_physmap case as will allocate another set of empty pages and leak the previous set. This privcmd_enforce_singleshot_mapping() stuff seems very odd anyway. Does anyone know what it was for originally? It would be preferrable if we could update the mappings with a new set of foreign MFNs without having to tear down the VMA and recreate a new VMA.> --- a/drivers/xen/privcmd.c > +++ b/drivers/xen/privcmd.c[...]> +/* For MMAPBATCH*. This allows asserting the singleshot mapping > + * on a per pfn/pte basis. Mapping calls that fail with ENOENT > + * can be then retried until success. */Comment coding style. David