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Baptiste Le Duc
861e44a3ba
Zihintpause is in required_extensions[] so Xen panics when it is missing, while it does not strictly require hardware support for it. The PAUSE hint (Zihintpause extension) is encoded as FENCE W, 0 (0x0100000F). In accordance with the RISC-V Unprivileged ISA, HINTs are encoded in the space of valid standard instructions. On platforms without Zihintpause support, executing 0x0100000F is treated as a standard FENCE with an empty successor set, which acts as a NOP and never generates an illegal instruction trap. Zihintpause is therefore purely an optimization hint. Drop it from required_extensions[] so Xen can still boot on systems that don't advertise it, and print a warning in that case. Assisted-by: Claude:claude-opus-5 Signed-off-by: Baptiste Le Duc <baptiste.le-duc@vates.tech> Reviewed-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
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