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Re: [PATCH v5 20/22] tests/tcg/aarch64: add test-sve-ioctl guest-debug t
From: |
Richard Henderson |
Subject: |
Re: [PATCH v5 20/22] tests/tcg/aarch64: add test-sve-ioctl guest-debug test |
Date: |
Wed, 5 Feb 2020 10:19:08 +0000 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 |
On 2/4/20 9:45 PM, Alex Bennée wrote:
>> Also, ZCR_EL1 it itself not correct if the
>> hardware does not support all vector sizes.
>>
>> See some of Andrew Jones' qemu command-line work. Try -cpu max,sve512=on and
>> then use the ioctl to set vq to 3 (sve384). The result will be an effective
>> vq
>> of 2 (sve256).
>>
>> We *really* need vg, as computed from sve_zcr_len_for_el().
>
> How come TARGET_PR_SVE_GET_VL is happy to compute directly from ZCR
> then?
Bug. It didn't get updated with Andrew's changes to limit the set of supported
sve lengths.
> I'll put the vg back in but it seemed a little pointless given the
> gdbstub ignores it.
I'll say again that this is a gdb bug and we should simply report/fix it
upstream. Don't try to work around it in qemu.
r~