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Re: [Qemu-arm] [Qemu-devel] [PATCH 05/13] target/arm/kvm: Add kvm_arch_g
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From: |
Peter Maydell |
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Subject: |
Re: [Qemu-arm] [Qemu-devel] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve |
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Date: |
Mon, 13 May 2019 16:40:52 +0100 |
On Mon, 13 May 2019 at 16:31, Dave Martin <address@hidden> wrote:
>
> On Mon, May 13, 2019 at 02:55:01PM +0100, Andrew Jones wrote:
> > QEMU keeps its 128-bit and larger words in the same order (least
> > significant word first) for both host endian types. We need to
> > do word swapping every time we set/get them to/from KVM.
>
> I'm not sure whether this is appropriate here, though it depends on
> what QEMU does with the data.
The layout is optimised for TCG emulation to be able
to work with it, I think (rth would have the definite
reason, though).
> Something non-obvious to be aware of:
>
> As exposed through the signal frame and the KVM ABI, the memory
> representation of an SVE reg is invariant with respect to the
> endianness.
Yes; we handle this conversion as we write out the signal frame:
https://github.com/qemu/qemu/blob/master/linux-user/aarch64/signal.c#L184
thanks
-- PMM
- [Qemu-arm] [PATCH 07/13] target/arm/kvm: max cpu: Allow sve max vector length setting, (continued)
- [Qemu-arm] [PATCH 07/13] target/arm/kvm: max cpu: Allow sve max vector length setting, Andrew Jones, 2019/05/12
- [Qemu-arm] [PATCH 04/13] target/arm/kvm: Move the get/put of fpsimd registers out, Andrew Jones, 2019/05/12
- [Qemu-arm] [PATCH 06/13] target/arm/kvm: max cpu: Enable SVE when available, Andrew Jones, 2019/05/12
- [Qemu-arm] [PATCH 12/13] target/arm/kvm: max cpu: Add support for sve-vls-map, Andrew Jones, 2019/05/12
- [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve, Andrew Jones, 2019/05/12
- Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve, Richard Henderson, 2019/05/13
- Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve, Andrew Jones, 2019/05/13
- Re: [Qemu-arm] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve, Richard Henderson, 2019/05/13
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