As with SVE we can only virtualise SME vector lengths that are supported by all CPUs in the system, implement similar checks to those for SVE. Since unlike SVE there are no specific vector lengths that are architecturally required the handling is subtly different, we report a system where this happens with a maximum vector length of 0.
Signed-off-by: Mark Brown <[email protected]> --- arch/arm64/kernel/fpsimd.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 5c156e2a47ea..7c4e69fd3922 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1277,6 +1277,7 @@ void __init sme_setup(void) * minimum available VL will be used. */ set_sme_default_vl(find_supported_vector_length(ARM64_VEC_SME, 32)); + info->max_virtualisable_vl = vec_virtualisable_vl(info); pr_info("SME: minimum available vector length %u bytes per vector\n", info->min_vl); @@ -1284,6 +1285,10 @@ void __init sme_setup(void) info->max_vl); pr_info("SME: default vector length %u bytes per vector\n", get_sme_default_vl()); + + /* KVM decides whether to support mismatched systems. Just warn here: */ + if (info->max_virtualisable_vl < info->max_vl) + pr_warn("SME: unvirtualisable vector lengths present\n"); } void sme_suspend_exit(void) -- 2.47.3
