Re: [PATCH v2 1/4] x86/boot: print CPU and APIC ID in bring up failure

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

On Thu, May 22, 2025 at 03:39:57PM +0100, Andrew Cooper wrote:
> On 22/05/2025 10:10 am, Jan Beulich wrote:
> > On 22.05.2025 09:54, Roger Pau Monne wrote:
> >> Print the CPU and APIC ID that fails to respond to the init sequence, or
> >> that didn't manage to reach the "callin" state.  Expand a bit the printed
> >> error messages.  Otherwise the "Not responding." message is not easy to
> >> understand by users.
> >>
> >> Reported-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> >> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
> >> ---
> >> Changes since v1:
> >>  - Also print APIC ID.
> >> ---
> >>  xen/arch/x86/smpboot.c | 6 ++++--
> >>  1 file changed, 4 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
> >> index 0189d6c332a4..dbc2f2f1d411 100644
> >> --- a/xen/arch/x86/smpboot.c
> >> +++ b/xen/arch/x86/smpboot.c
> >> @@ -618,10 +618,12 @@ static int do_boot_cpu(int apicid, int cpu)
> >>              smp_mb();
> >>              if ( bootsym(trampoline_cpu_started) == 0xA5 )
> >>                  /* trampoline started but...? */
> >> -                printk("Stuck ??\n");
> >> +                printk("CPU%u/APICID%u: Didn't finish startup sequence\n",
> >> +                       cpu, apicid);
> >>              else
> >>                  /* trampoline code not run */
> >> -                printk("Not responding.\n");
> >> +                printk("CPU%u/APICID%u: Not responding to startup\n",
> >> +                       cpu, apicid);
> >>          }
> >>      }
> >>  
> > Elsewhere I think we print AIC IDs in hex; may be better to do so here, too.
> > That may then want some text re-arrangement though, e.g.
> >
> > "CPU%u: APICID %#x not responding to startup\n"
> >
> > Thoughts?
> 
> Definitely hex.  Elsewhere APIC_ID always has an underscore.

Maybe I'm confused, but I don't think Xen uses an underscore, it's
always 'APIC ID' when printed.  I don't mind adding it here, I assume
what you mean with elsewhere is other projects like Linux?

Thanks, Roger.