Re: [patch v3 31/36] x86/apic: Provide cpu_primary_thread mask

Kirill A. Shutemov
2023-05-29T20:31:44Z

On Mon, May 29, 2023 at 09:27:13PM +0200, Thomas Gleixner wrote:
> On Mon, May 29 2023 at 05:39, Kirill A. Shutemov wrote:
> > On Sat, May 27, 2023 at 03:40:02PM +0200, Thomas Gleixner wrote:
> > But it gets broken again on "x86/smpboot: Implement a bit spinlock to
> > protect the realmode stack" with
> >
> > [ 0.554079] .... node #0, CPUs: #1 #2
> > [ 0.738071] Callback from call_rcu_tasks() invoked.
> > [ 10.562065] CPU2 failed to report alive state
> > [ 10.566337] #3
> > [ 20.570066] CPU3 failed to report alive state
> > [ 20.574268] #4
> > ...
> >
> > Notably CPU1 is missing from "failed to report" list. So CPU1 takes the
> > lock fine, but seems never unlocks it.
> >
> > Maybe trampoline_lock(%rip) in head_64.S somehow is not the same as
> > &tr_lock in trampoline_64.S. I donno.
>
> It's definitely the same in the regular startup (16bit mode), but TDX
> starts up via:
>
> trampoline_start64
> trampoline_compat
> LOAD_REALMODE_ESP <- lock
>
> That place cannot work with that LOAD_REALMODE_ESP macro. The untested
> below should cure it.

Yep, works for me.

Aaand the next patch that breaks TDX boot is... <drum roll>

x86/smpboot/64: Implement arch_cpuhp_init_parallel_bringup() and enable it

Disabling parallel bringup helps. I didn't look closer yet. If you have
an idea let me know.

--
Kiryl Shutsemau / Kirill A. Shutemov