commit d643cfefac129595d3502d709bd3d4128f2ada1e
author Pierre-Clément Tosi <ptosi@google.com> Thu Jun 29 09:30:51 2023 +0000
committer Pierre-Clément Tosi <ptosi@google.com> Fri Jul 07 10:45:17 2023 +0000
tree 5e2808800d699297d3428a2c415d5074cbf2cccd
parent 32279ef5c46ab5081638e87d8d4c89d940a1b4c1

hyp: Refactor HypervisorCap to harden backends

The Hypervisor trait previously required backends to implement all of
its functions, even when they related to features that their underlying
hypervisor did not implement. To deal with this, capabilities were
introduced so that client code would conditionally call those functions
based on the availability of the feature (discovered through the
capabilities). This resulted in useless boiler-plate code in the
backends (either using unimplemented()! or returning placeholders to
please the caller) and a high risk of making use of unavailable features
in hypervisor-agnostic client code.

Instead, rework Hypervisor as an Inlineable Dyn Extension Trait [1],
making it programmatically impossible to call a function for a feature
that the running hypervisor doesn't provide. This also removes the need
for any boilerplate code in the backends.

Introduce the accessors get_mmio_guard() and get_mem_sharer().

No functional change intended.

[1]: https://github.com/daniel5151/inlinable-dyn-extension-traits/blob/master/writeup.md

Test: atest DebugPolicyHostTests#testNoAdbInDebugPolicy_withDebugLevelNone_boots
Test: atest rialto_test vmbase_example.integration_test
Change-Id: I6404fa141f53d074c9529403c4606ab90867cf6c