[ci] Frail attempt to fix riscv qemu run

Author: serge-sans-paille

.github/workflows/cross-rvv-arch.yml

@@ -1,13 +1,5 @@
 # RISC-V RVV cross-compilation build (Ubuntu apt qemu, multi-compiler matrix).
 #
-# vlen=128 is intentionally NOT covered here. Ubuntu's qemu-user-static
-# (8.2.x in noble, 9.x in plucky) hangs on the xsimd test_xsimd binary at
-# vlen=128 — see QEMU issue #2137 (RVV TCG slowdowns) for the underlying
-# emulator behaviour. Until ubuntu-latest ships qemu 11+, vlen=128 coverage
-# lives in cross-rvv-arch.yml, which runs inside an archlinux:latest
-# container with qemu 11. Vlens >= 256 run fast enough under the apt qemu
-# to stay within the test step's timeout.
-#
 # References:
 #   QEMU 11.0.0 release notes:  https://www.qemu.org/2026/04/22/qemu-11-0-0/
 #   QEMU RVV slowdowns issue:   https://gitlab.com/qemu-project/qemu/-/issues/2137
@@ -29,6 +21,7 @@ jobs:
           - { compiler: 'clang', version: '17', gcc_runtime: '14'}
           - { compiler: 'clang', version: '18', gcc_runtime: '14'}
         vector_bits:
+          - 128
           - 256
           - 512
     steps: