[xen master] x86/NMI: refine "watchdog stuck" log message

[patchbot@xxxxxxx]

commit f575f055243eda56e6f1f26eee5bf3646281f122
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Thu Jan 25 16:10:06 2024 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jan 25 16:10:06 2024 +0100

    x86/NMI: refine "watchdog stuck" log message
    
    Observing
    
    "Testing NMI watchdog on all CPUs: 0 stuck"
    
    it felt like it's not quite right, but I still read it as "no CPU stuck;
    all good", when really the system suffered from what 6bdb965178bb
    ("x86/intel: ensure Global Performance Counter Control is setup
    correctly") works around. Convert this to
    
    "Testing NMI watchdog on all CPUs: {0} stuck"
    
    or, with multiple CPUs having an issue, e.g.
    
    "Testing NMI watchdog on all CPUs: {0,40} stuck"
    
    to make more obvious that a lone number is not a count of CPUs.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Acked-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/nmi.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/xen/arch/x86/nmi.c b/xen/arch/x86/nmi.c
index dc79c25e3f..633dc59bf8 100644
--- a/xen/arch/x86/nmi.c
+++ b/xen/arch/x86/nmi.c
@@ -167,13 +167,14 @@ static void __init cf_check wait_for_nmis(void *p)
 void __init check_nmi_watchdog(void)
 {
     static unsigned int __initdata prev_nmi_count[NR_CPUS];
-    int cpu;
+    unsigned int cpu;
+    char sep = '{';
     bool ok = true;
 
     if ( nmi_watchdog == NMI_NONE )
         return;
 
-    printk("Testing NMI watchdog on all CPUs:");
+    printk("Testing NMI watchdog on all CPUs: ");
 
     for_each_online_cpu ( cpu )
         prev_nmi_count[cpu] = per_cpu(nmi_count, cpu);
@@ -189,12 +190,13 @@ void __init check_nmi_watchdog(void)
     {
         if ( per_cpu(nmi_count, cpu) - prev_nmi_count[cpu] < 2 )
         {
-            printk(" %d", cpu);
+            printk("%c%u", sep, cpu);
+            sep = ',';
             ok = false;
         }
     }
 
-    printk(" %s\n", ok ? "ok" : "stuck");
+    printk("%s\n", ok ? "ok" : "} stuck");
 
     /*
      * Now that we know it works we can reduce NMI frequency to
--
generated by git-patchbot for /home/xen/git/xen.git#master