On Fri, 17 Oct 2025 19:06:25 +0200, Marc Zyngier maz@kernel.org wrote:
* We use linear CPU numbers for redistributor addressing, * so GITS_TYPER.PTA is 0.It is not an address.
The issue is that its_encode_target in selftests is designed for physical redistriubtor addresses (GITS_TYPER.PTA = 1) and thus performs a right shift by 16 bits:
its_mask_encode(&cmd->raw_cmd[2], target_addr >> 16, 51, 16);
When the vgic_lpi_stress selftest passes in a linear vCPU id as the redistributor address (GITS_TYPER.PTA = 0 behavior), The its_encode_target function shifts the CPU numbers 16 bits right, functionally zeroing them.
We need to either: - Align this specific selftest with GITS_TYPER.PTA = 0 and not use its_encode_target to encode the target vCPU id. Instead have a dedicated encode function for the use case without a bit shift. - Align all selftests with GITS_TYPER.PTA = 0 and refactor its_encode_target to skip the bit shift altogether. - Align selftests with GITS_TYPER.PTA = 1 and pass a redistributor address, not a vCPU id, into its_send_mapc_cmd().
Otherwise, the selftest's current behavior incorrectly maps all collections to target vCPU 0.
Thanks, Maximilian
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