[{"id":3678358,"web_url":"http://patchwork.ozlabs.org/comment/3678358/","msgid":"","list_archive_url":null,"date":"2026-04-16T19:55:28","subject":"Re: [PATCH v2 2/3] target/arm: Allow 'aarch64=off' to be set for TCG\n CPUs","submitter":{"id":85046,"url":"http://patchwork.ozlabs.org/api/people/85046/","name":"Philippe Mathieu-Daudé","email":"philmd@linaro.org"},"content":"On 16/4/26 18:53, Peter Maydell wrote:\n> Allow the 'aarch64=off' property, which is currently KVM-only, to\n> be set for TCG CPUs also.\n> \n> Note that we don't permit it on the qemu-aarch64 user-mode binary:\n> this makes no sense as that executable can only handle AArch64\n> syscalls (and it would also assert at startup since it doesn't\n> compile in the A32-specific GDB xml files like arm-neon.xml).\n> \n> Signed-off-by: Peter Maydell \n> Reviewed-by: Richard Henderson \n> Tested-by: Clément Chigot \n> ---\n> v1->v2: slight tweak to the docs wording\n> ---\n> docs/system/arm/cpu-features.rst | 10 +++++----\n> target/arm/cpu-features.h | 5 +++++\n> target/arm/cpu.c | 36 ++++++++++++++++++++++++++++----\n> tests/qtest/arm-cpu-features.c | 8 ++-----\n> 4 files changed, 45 insertions(+), 14 deletions(-)\n\n\n> + bool aa32_at_highest_el;\n> + if (arm_feature(&cpu->env, ARM_FEATURE_EL3)) {\n> + aa32_at_highest_el = cpu_isar_feature(aa64_aa32_el3, cpu);\n> + } else if (arm_feature(&cpu->env, ARM_FEATURE_EL2)) {\n> + aa32_at_highest_el = cpu_isar_feature(aa64_aa32_el2, cpu);\n> + } else {\n> + aa32_at_highest_el = cpu_isar_feature(aa64_aa32_el1, cpu);\n> + }\n> +\n> + if (!aa32_at_highest_el) {\n> + error_setg(errp, \"'aarch64' feature cannot be disabled for \"\n> + \"this TCG CPU because it does not support 32-bit \"\n> + \"execution at its highest implemented exception \"\n> + \"level\");\n> + return;\n> + }\n\nNice.\n\nReviewed-by: Philippe Mathieu-Daudé ","headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=linaro.org header.i=@linaro.org header.a=rsa-sha256\n header.s=google header.b=WvqtM82z;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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