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Add `handle_hvc` to the `Platform` trait, enabling custom EL2 HVC calls for specific platforms. Unhandled HVCs are properly trapped and routed to this method. If a platform doesn't handle the HVC, it now returns SMCCC_NOT_SUPPORTED (-1) to the guest instead of panicking. Added a dummy HVC (0xFF00_0000) to the QEMU platform implementation for testing purposes. The `integration_test` (formerly called `isolation_test`) validates both successful dummy HVC execution and expected failure for unknown HVCs.
qwandor
reviewed
Mar 27, 2026
src/platform/qemu.rs
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| if function_id == 0xFF00_0000 { | ||
| // SAFETY: We only modify the state of the x0 register as an answer to the | ||
| // guest call. | ||
| let regs = unsafe { register_state.get_mut() }; |
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It would be nice to provide a safe abstraction for platforms to handle HVCs. Maybe rather than passing the RegisterStateRef you could pass a mutable reference to the subset of registers which the SMCCC allows to be changed by an HVC call? I guess this handler shouldn't need to change the FP, SP, ELR or SPSR, right?
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Fair - I changed the API so that handle_hvc now return a custom error. The nice part is that some of the logic can be shared with the PSCI proxy code.
Let me know if this makes sense.
qwandor
approved these changes
Mar 30, 2026
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Add
handle_hvcto thePlatformtrait, enabling custom EL2 HVC calls for specific platforms. Unhandled HVCs are properly trapped and routed to this method. If a platform doesn't handle the HVC, it now returns SMCCC_NOT_SUPPORTED (-1) to the guest instead of panicking.Added a dummy HVC (0xFF00_0000) to the QEMU platform implementation for testing purposes. The
integration_test(formerly calledisolation_test) validates both successful dummy HVC execution and expected failure for unknown HVCs.