diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2021-07-23 10:33:44 -1000 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2021-07-27 10:57:40 +0100 |
| commit | b3d52804c591b478ec0620253c2bd71e4ff87bb9 (patch) | |
| tree | 287bbaa7f2a03b6e837dae465cee9d75b1118dd7 /target/arm/cpu.c | |
| parent | ce440581c1446e56d911d83c9c3b760ae4f98b3e (diff) | |
target/arm: Add sve-default-vector-length cpu property
Mirror the behavour of /proc/sys/abi/sve_default_vector_length
under the real linux kernel. We have no way of passing along
a real default across exec like the kernel can, but this is a
decent way of adjusting the startup vector length of a process.
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/482
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20210723203344.968563-4-richard.henderson@linaro.org
[PMM: tweaked docs formatting, document -1 special-case,
added fixup patch from RTH mentioning QEMU's maximum veclen.]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'target/arm/cpu.c')
| -rw-r--r-- | target/arm/cpu.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/target/arm/cpu.c b/target/arm/cpu.c index 752b15bb79..2866dd7658 100644 --- a/target/arm/cpu.c +++ b/target/arm/cpu.c @@ -201,7 +201,8 @@ static void arm_cpu_reset(DeviceState *dev) env->cp15.cpacr_el1 = deposit64(env->cp15.cpacr_el1, 16, 2, 3); /* with reasonable vector length */ if (cpu_isar_feature(aa64_sve, cpu)) { - env->vfp.zcr_el[1] = MIN(cpu->sve_max_vq - 1, 3); + env->vfp.zcr_el[1] = + aarch64_sve_zcr_get_valid_len(cpu, cpu->sve_default_vq - 1); } /* * Enable TBI0 but not TBI1. @@ -1051,7 +1052,16 @@ static void arm_cpu_initfn(Object *obj) QLIST_INIT(&cpu->pre_el_change_hooks); QLIST_INIT(&cpu->el_change_hooks); -#ifndef CONFIG_USER_ONLY +#ifdef CONFIG_USER_ONLY +# ifdef TARGET_AARCH64 + /* + * The linux kernel defaults to 512-bit vectors, when sve is supported. + * See documentation for /proc/sys/abi/sve_default_vector_length, and + * our corresponding sve-default-vector-length cpu property. + */ + cpu->sve_default_vq = 4; +# endif +#else /* Our inbound IRQ and FIQ lines */ if (kvm_enabled()) { /* VIRQ and VFIQ are unused with KVM but we add them to maintain |