Hello Denis, > After a restore of a component the capability space shall be the "same" > as before the checkpoint: > 1) The capabilities after the restore shall point to corresponding > object identities. > 2) Also the capabilities after the restore shall be on the same slot > (have the same address) in the capability space as before the checkpoint. > > The capability space resides in the kernel and Genode does not offer an > API to manipulate it. Is there a way to accomplish my goal with Genode's > API anyway?
there is no ready-to-use solution via the Genode API because the way capabilities are handled vastly differs between the various kernels. Manipulating the capability space of a remote component wouldn't even be possible on some kernels. However, since you are using a specific kernel (Fiasco.OC) that provides an asynchronous map operation, the problem can be tackled in a kernel-specific way. I would propose to extend the existing 'Foc_native_pd' RPC interface [1] with RPC functions for requesting and installing capabilities from/into the capability space of the PD. [1] https://github.com/genodelabs/genode/tree/master/repos/base-foc/include/foc_native_pd The function for requesting a capability would have an iterator-like interface that allows the client to iterate over the PD-local selector numbers and sequentially obtain the underlying capabilities as Genode::Native_capability objects (which can be delegated via RPC). Each call would return a Genode::Native_capability and a selector number of the capability to request with the next RPC call. In a first version, you may simply iterate over all numbers up to the maximum selector number, returning invalid capabilities for unused selectors. The iterator-like interface would then be a performance optimization. The function for installing a capability would take a Genode::Native_capability and the destination selector number as arguments. The implementation of the 'Foc_native_pd' interface resides in core, which has access to all capabilities. The implementation would directly issue Fiasco.OC system calls (most likely 'l4_task_map') to install the given capability into the targeted PD. Does this sound like a reasonable plan? Cheers Norman -- Dr.-Ing. Norman Feske Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth ------------------------------------------------------------------------------ _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
