Re: [Qemu-arm] [Qemu-devel] [PATCH 05/13] target/arm/kvm: Add kvm_arch_get/put_sve

[Dave Martin]

On Mon, May 13, 2019 at 05:58:59PM +0100, Richard Henderson wrote:
> On 5/13/19 7:39 AM, Dave Martin wrote:
> > On that point, could TCG easily be made to expose a larger vector length
> > to the kernel?  I'd be interested to see what happened.
> 
> It would be easy enough to extend the maximum vector length within TCG.
> 
> Increase ARM_MAX_VQ.  Alter the couple of places where we manipulate ZCR.LEN 
> to
> extend the current 4-bit mask.
> 
> How large do you need the max to be, for testing?

Anything upwards of 256 bytes is interesting.

The architecture reserves space for it to grow up to 9 bits, though it's
unlikely it would ever get that large in reality.

So if you wanted to go crazy, you might be able to go up to 8192 bytes.

This is just for fun, since it goes outside the architecture and Linux
officially doesn't support it today in any case.  So definitely not a
priority!

Cheers
---Dave