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

[Juergen Gross <jgross@xxxxxxxx>]

On 27.06.22 12:28, Roger Pau Monné wrote:
> 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.
This would end up in Arm suddenly supporting the sub-ops it doesn't
(want to) support today. Otherwise it would make no sense that Arm has
a dedicated entry for this hypercall.

The "common" just wants to express that the code is common. I'm open
for a better suggestion, though. :-)


Juergen

Attachment: OpenPGP_0xB0DE9DD628BF132F.asc
Description: OpenPGP public key

Attachment: OpenPGP_signature
Description: OpenPGP digital signature