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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 > --- > Changes since v2: > - rewrite commit message > - print a warning at boot when Zihintpause is unavailable > - drop Zihintpause requirement from booting.txt > --- > Changes since v1: > - rewrite commit message. > --- LGTM: Reviewed-by: Oleksii Kurochko Thanks. ~ Oleksii