which CPUs should call aarch64_add_{sve,pauth,sme}_properties() ?

which CPUs should call aarch64_add_{sve,pauth,sme}_properties() ?

[Peter Maydell]

At the moment:
 * aarch64_a64fx_initfn() calls aarch64_add_sve_properties()
 * aarch64_max_tcg_initfn() calls all of
   aarch64_add_pauth_properties(), aarch64_add_sve_properties(),
   aarch64_add_sme_properties()

and it happens that (ignoring 'max') we only have a64fx implementing SVE
and no CPUs implementing Pauth or SME yet.

Is the idea that all CPUs (both ones trying to match real hardware
and ones which are QEMU-specific like 'max') should call these
functions to set up the properties if they exist? Or is the idea
that 'max' is special and match-real-hardware CPUs don't need the
user-facing configurability?

If the former, maybe it would be better to put these in
arm_cpu_post_init() so they're automatically called if the CPU
specific initfn set the ID register value that indicates the
presence of pauth/sve/sme.

If the latter, A64FX is an odd-one-out for creating the SVE props.

I ask because Neoverse-V1 has both SVE and Pauth, and I'm not
sure if its init fn should be calling these functions.

thanks
-- PMM

Re: which CPUs should call aarch64_add_{sve, pauth, sme}_properties() ?

[Richard Henderson]

On 6/26/23 18:54, Peter Maydell wrote:
> At the moment:
>   * aarch64_a64fx_initfn() calls aarch64_add_sve_properties()
>   * aarch64_max_tcg_initfn() calls all of
>     aarch64_add_pauth_properties(), aarch64_add_sve_properties(),
>     aarch64_add_sme_properties()
> 
> and it happens that (ignoring 'max') we only have a64fx implementing SVE
> and no CPUs implementing Pauth or SME yet.
> 
> Is the idea that all CPUs (both ones trying to match real hardware
> and ones which are QEMU-specific like 'max') should call these
> functions to set up the properties if they exist? Or is the idea
> that 'max' is special and match-real-hardware CPUs don't need the
> user-facing configurability?

Set up properties if they exist was the idea, I think.

> If the former, maybe it would be better to put these in
> arm_cpu_post_init() so they're automatically called if the CPU
> specific initfn set the ID register value that indicates the
> presence of pauth/sve/sme.

I thought there was some weirdness with kvm and -cpu host.

> I ask because Neoverse-V1 has both SVE and Pauth, and I'm not
> sure if its init fn should be calling these functions.

I would say so.


r~