diff options
| author | Richard Henderson <richard.henderson@linaro.org> | 2018-08-16 14:05:28 +0100 |
|---|---|---|
| committer | Peter Maydell <peter.maydell@linaro.org> | 2018-08-16 14:05:28 +0100 |
| commit | adf92eab90e3f5f34c285da6d14d48952b7a8e72 (patch) | |
| tree | b7001056fc891aab12aa36908a884de7e3555543 /linux-user | |
| parent | 2bf5f3f91bb4e3faa2a19aec042138a938afbf6a (diff) | |
target/arm: Add sve-max-vq cpu property to -cpu max
This allows the default (and maximum) vector length to be set
from the command-line. Which is extraordinarily helpful in
debugging problems depending on vector length without having to
bake knowledge of PR_SET_SVE_VL into every guest binary.
Cc: qemu-stable@nongnu.org (3.0.1)
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'linux-user')
| -rw-r--r-- | linux-user/syscall.c | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c index dfc851cc35..5a4af76c03 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -10848,15 +10848,22 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif #ifdef TARGET_AARCH64 case TARGET_PR_SVE_SET_VL: - /* We cannot support either PR_SVE_SET_VL_ONEXEC - or PR_SVE_VL_INHERIT. Therefore, anything above - ARM_MAX_VQ results in EINVAL. */ + /* + * We cannot support either PR_SVE_SET_VL_ONEXEC or + * PR_SVE_VL_INHERIT. Note the kernel definition + * of sve_vl_valid allows for VQ=512, i.e. VL=8192, + * even though the current architectural maximum is VQ=16. + */ ret = -TARGET_EINVAL; if (arm_feature(cpu_env, ARM_FEATURE_SVE) - && arg2 >= 0 && arg2 <= ARM_MAX_VQ * 16 && !(arg2 & 15)) { + && arg2 >= 0 && arg2 <= 512 * 16 && !(arg2 & 15)) { CPUARMState *env = cpu_env; - int old_vq = (env->vfp.zcr_el[1] & 0xf) + 1; - int vq = MAX(arg2 / 16, 1); + ARMCPU *cpu = arm_env_get_cpu(env); + uint32_t vq, old_vq; + + old_vq = (env->vfp.zcr_el[1] & 0xf) + 1; + vq = MAX(arg2 / 16, 1); + vq = MIN(vq, cpu->sve_max_vq); if (vq < old_vq) { aarch64_sve_narrow_vq(env, vq); |