This adds sufficient kernel support for the GICv3 interrupt controller
to be used in a virtualization context on aarch64.
This set of changes has some limitations, however it is still an
improvement on the status quo.
Limitations:
1: This only provides support for aarch64. Anyone wanting support
for aarch32 + GICv3 + virtualization would need to add additional
code.
2: This code only supports 32 priority levels. Support for more
than 32 priority requires changing the get/set_gic_vcpu_ctrl_apr
interface. This is feasible, but requires a more invasive set of
changes. 32 priority levels has been shown to be sufficient in
practise.
Impacts on verification:
This set of changes should only impact Aarch64 Hypervisor
configurations. This is not yet verified so should not have
an impact on verification.
Level of testing:
This has been tested on an iMX8QXP based board. Testing
has at this point in time been limited to a single virtual
machine.
Note: support for this board is not yet upstrea, but is
currently being prepared.
Explanation of changes:
Ideally a new config item would not be required and this
could be driven purely by DTS and hardware.yml configuration.
However, the structures.bf requires changes. This can only
deal with config.h header files, not other more complex
header files. As such it was necessary to introduce a config
item which can be used for this purpose.
The appropriate platforms (as determined by examination of
DTS files) have been updated with the appropriate config
setting. This config setting only has any relevance if
hypervisor mode is already enabled, so should not cause
any difficulty for existing code or configuration.
Note: No testing has been performed on the updated
platforms.
There may be alternative factorings of this, which could
be considered in future work.
Signed-off-by: Ben Leslie <benno@brkawy.com>
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