Re: [PATCH v6 1/9] xen: move do_vcpu_op() to arch specific code

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Thu, Mar 24, 2022 at 03:01:31PM +0100, Juergen Gross wrote:
> The entry point used for the vcpu_op hypercall on Arm is different
> from the one on x86 today, as some of the common sub-ops are not
> supported on Arm. The Arm specific handler filters out the not
> supported sub-ops and then calls the common handler. This leads to the
> weird call hierarchy:
> 
>   do_arm_vcpu_op()
>     do_vcpu_op()
>       arch_do_vcpu_op()
> 
> Clean this up by renaming do_vcpu_op() to common_vcpu_op() and
> arch_do_vcpu_op() in each architecture to do_vcpu_op(). This way one
> of above calls can be avoided without restricting any potential
> future use of common sub-ops for Arm.

Wouldn't it be more natural to have do_vcpu_op() contain the common
code (AFAICT handlers for
VCPUOP_register_{vcpu_info,runstate_memory_area}) and then everything
else handled by the x86 arch_do_vcpu_op() handler?

I find the common prefix misleading, as not all the VCPUOP hypercalls
are available to all the architectures.

Thanks, Roger.