Re: [RFC v11 45/55] target/arm: cpu-sve: new module

[Claudio Fontana]

On 3/25/21 7:48 PM, Claudio Fontana wrote:
> On 3/25/21 7:40 PM, Richard Henderson wrote:
>> On 3/23/21 9:46 AM, Claudio Fontana wrote:
>>> extract the SVE-related cpu object properties and functions,
>>> and move them to a separate module.
>>>
>>> Disentangle SVE from pauth that is a separate, TCG-only feature.
>>>
>>> Signed-off-by: Claudio Fontana <cfontana@suse.de>
>>> ---
>>>   target/arm/cpu-sve.h     |  40 +++++
>>>   target/arm/cpu.h         |  22 +--
>>>   target/arm/cpu-sve.c     | 360 +++++++++++++++++++++++++++++++++++++++
>>>   target/arm/cpu.c         |   5 +-
>>>   target/arm/cpu64.c       | 333 +-----------------------------------
>>>   target/arm/kvm/kvm-cpu.c |   2 +-
>>>   target/arm/meson.build   |   1 +
>>>   7 files changed, 417 insertions(+), 346 deletions(-)
>>>   create mode 100644 target/arm/cpu-sve.h
>>>   create mode 100644 target/arm/cpu-sve.c
>>>
>>> diff --git a/target/arm/cpu-sve.h b/target/arm/cpu-sve.h
>>> new file mode 100644
>>> index 0000000000..b1be575265
>>> --- /dev/null
>>> +++ b/target/arm/cpu-sve.h
>>> @@ -0,0 +1,40 @@
>>> +/*
>>> + * QEMU AArch64 CPU SVE Extensions for TARGET_AARCH64
>>> + *
>>> + * Copyright (c) 2013 Linaro Ltd
>>> + *
>>> + * This program is free software; you can redistribute it and/or
>>> + * modify it under the terms of the GNU General Public License
>>> + * as published by the Free Software Foundation; either version 2
>>> + * of the License, or (at your option) any later version.
>>> + *
>>> + * This program is distributed in the hope that it will be useful,
>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>>> + * GNU General Public License for more details.
>>> + *
>>> + * You should have received a copy of the GNU General Public License
>>> + * along with this program; if not, see
>>> + * <http://www.gnu.org/licenses/gpl-2.0.html>
>>> + */
>>> +
>>> +#ifndef CPU_SVE_H
>>> +#define CPU_SVE_H
>>> +
>>> +/* note: SVE is an AARCH64-only option, only include this for 
>>> TARGET_AARCH64 */
>>> +
>>> +/* called by arm_cpu_finalize_features in realizefn */
>>> +void cpu_sve_finalize_features(ARMCPU *cpu, Error **errp);
>>> +
>>> +/* add the CPU SVE properties */
>>> +void cpu_sve_add_props(Object *obj);
>>> +
>>> +/* add the CPU SVE properties specific to the "MAX" CPU */
>>> +void cpu_sve_add_props_max(Object *obj);
>>> +
>>> +/* In AArch32 mode, predicate registers do not exist at all.  */
>>> +typedef struct ARMPredicateReg {
>>> +    uint64_t p[DIV_ROUND_UP(2 * ARM_MAX_VQ, 8)] QEMU_ALIGNED(16);
>>> +} ARMPredicateReg;
>>
>> I don't agree with moving this out of cpu.h, next to the rest of the vector 
>> definitions.
>>
>> I agree that we should be using more files, but if we're going to have an 
>> cpu-sve.c, why did some of the sve functions go into cpu-common.c?


actually, now that the option of making those SVE functions in cpu-common.c 
TARGET_AARCH64-specific is open,
we could attempt to import them in cpu-sve.

I'll give it a try, lets see the result.


> 
> maybe cpu-sve-props.c would be a better name, it really contains only cpu sve 
> properties code.
> 
>>
>> I don't agree with moving functions and renaming them simultaneously.  I'm 
>> not 
>> even sure why you're renaming them, or why you've suddenly chosen 
>> "cpu_sve_*" 
>> as the prefix to use.
>>
>>
>> r~
>>
> 
> I think the idea was trying to create a cpu_sve module handling everything 
> related to sve,
> and consistently using the name of the module as the prefix.
> 
> It might be too early to attempt that anyway; as you noted, there is other 
> SVE-related functionality all over the place,
> so better to revisit this.
> 
> I'd suggest renaming this to cpu_sve_props, and moving everything not props 
> related out of it.
> 
> Thanks,
> 
> Claudio
> 
> 
> 
>