[v2] target/arm/hvf: Consolidate

[PATCH v2 58/58] target/arm: Only allow disabling NEON when using TCG

Posted by Philippe Mathieu-Daudé 3 weeks, 1 day ago

Only allow disabling NEON when using TCG.

This avoids confusing user experience:

  $ qemu-system-aarch64 -M virt -accel hvf \
                        -cpu host,neon=off,vfp=off,vfp-d32=off
  qemu-system-aarch64: AArch64 CPUs must have both VFP and Neon or neither

  $ qemu-system-aarch64 -M virt -accel hvf \
                        -cpu host,neon=off,vfp=off,vfp-d32=off
  qemu-system-aarch64: ARM CPUs must have both VFP-D32 and Neon or neither

  $ qemu-system-aarch64 -M virt -accel hvf \
                        -cpu host,neon=off,vfp=off,vfp-d32=off
  qemu-system-aarch64: can't apply global host-arm-cpu.vfp-d32=off: Property 'host-arm-cpu.vfp-d32' not found

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 target/arm/cpu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index bfd3b57e8a8..9343c6093b9 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -1457,7 +1457,7 @@ static void arm_cpu_post_init(Object *obj)
 
     if (arm_feature(&cpu->env, ARM_FEATURE_NEON)) {
         cpu->has_neon = true;
-        if (!kvm_enabled()) {
+        if (tcg_enabled() || qtest_enabled()) {
             qdev_property_add_static(DEVICE(obj), &arm_cpu_has_neon_property);
         }
     }
-- 
2.51.0

Re: [PATCH v2 58/58] target/arm: Only allow disabling NEON when using TCG

Posted by Richard Henderson 2 weeks, 6 days ago

On 10/23/25 14:31, Philippe Mathieu-Daudé wrote:
> Only allow disabling NEON when using TCG.
> 
> This avoids confusing user experience:
> 
>    $ qemu-system-aarch64 -M virt -accel hvf \
>                          -cpu host,neon=off,vfp=off,vfp-d32=off
>    qemu-system-aarch64: AArch64 CPUs must have both VFP and Neon or neither
> 
>    $ qemu-system-aarch64 -M virt -accel hvf \
>                          -cpu host,neon=off,vfp=off,vfp-d32=off
>    qemu-system-aarch64: ARM CPUs must have both VFP-D32 and Neon or neither
> 
>    $ qemu-system-aarch64 -M virt -accel hvf \
>                          -cpu host,neon=off,vfp=off,vfp-d32=off
>    qemu-system-aarch64: can't apply global host-arm-cpu.vfp-d32=off: Property 'host-arm-cpu.vfp-d32' not found
> 
> Signed-off-by: Philippe Mathieu-Daudé<philmd@linaro.org>
> ---
>   target/arm/cpu.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~