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Re: [PATCH v2 1/8] x86/xen/pv: Don't setup runstate area too early


  • To: Teddy Astie <teddy.astie@xxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • Date: Fri, 16 Oct 2026 18:33:53 +0100
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  • Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>, David Woodhouse <dwmw2@xxxxxxxxxxxxx>, x86@xxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
  • Delivery-date: Fri, 16 Oct 2026 17:34:07 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 16/10/2026 6:06 pm, Teddy Astie wrote:
> This is no longer required since [1].
>
> At this moment of boot, per_cpu areas are not initialized, which prevents
> using VCPUOP_register_runstate_phys_area as per_cpu_ptr_to_phys() would
> misbehave in this case.

This isn't really correct.

The per-cpu area for the BSP is within the main image, which is why the
logic functions today.  What's missing is the call to
pcpu_setup_first_chunk() which tells per_cpu_ptr_to_phys() about where
the BSP data is.

I think you want to say:

"A future change wants to use per_cpu_ptr_to_phys() in
xen_setup_runstate_info(), but this call is too early.  It turns out to
be no longer required since ..."

>
> [1] 8a22b9996b00 ("xen: drop xen_sched_clock in favour of using plain 
> wallclock time")
> ---

Missing SoB.

~Andrew



 


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