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Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve
From: |
Richard Henderson |
Subject: |
Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve |
Date: |
Mon, 13 May 2019 11:31:26 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
On 5/13/19 11:14 AM, Andrew Jones wrote:
>> Indeed, to me this seems to be the wrong kind of swabbing here. Exactly what
>> format is KVM expecting? Surely it should be the one used by the
>> unpredicated
>> LDR/STR instructions. Anything else would seem to be working against the
>> architecture.
>>
>> If so, the format is, architecturally, a stream of bytes in index order,
>> which
>> corresponds to a little-endian stream of words. So the loop I'd expect to
>> see
>> here is
>>
>> for (i = 0, n = cpu->sve_max_vq; i < n; ++i) {
>> d[i] = bswap64(q[i]);
>> }
>
> That's the opposite of what we do for fpsimd registers though. I'm
> fine with doing whatever KVM/TCG needs, but so far I was just following
> the same pattern we already have.
The behaviour of the hardware is different for LDR of fpsimd registers.
FP&SIMD LDR operates on datasize (8, 16, 32, 64, 128 bits).
SVE LDR always operates on bytes.
r~
Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve, Dave Martin, 2019/05/13
[Qemu-arm] [PATCH 03/13] HACK: linux header update, Andrew Jones, 2019/05/12
[Qemu-arm] [PATCH 11/13] target/arm/cpu64: max cpu: Introduce sve-vls-map, Andrew Jones, 2019/05/12