[xen master] x86/APIC: modify error_interrupt() to output using single printk()

[patchbot@xxxxxxx]

commit 6960e343d6b374196e6af585532d058d58585027
Author:     Elliott Mitchell <ehem+xen@xxxxxxx>
AuthorDate: Thu Jul 13 16:58:56 2023 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Jul 13 16:58:56 2023 +0200

    x86/APIC: modify error_interrupt() to output using single printk()
    
    This takes care of the issue of APIC errors tending to occur on multiple
    cores at once.  In turn this tends to causes the error messages to be
    merged together, making understanding them difficult.
    
    Signed-off-by: Elliott Mitchell <ehem+xen@xxxxxxx>
    Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/x86/apic.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/xen/arch/x86/apic.c b/xen/arch/x86/apic.c
index 8cfb8cd71c..08459228e0 100644
--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -1410,6 +1410,7 @@ static void cf_check error_interrupt(struct cpu_user_regs 
*regs)
         ", Received illegal vector",
         ", Illegal register address",
     };
+    const char *entries[ARRAY_SIZE(esr_fields)];
     unsigned int v, v1;
     int i;
 
@@ -1419,12 +1420,13 @@ static void cf_check error_interrupt(struct 
cpu_user_regs *regs)
     v1 = apic_read(APIC_ESR);
     ack_APIC_irq();
 
-    printk(XENLOG_DEBUG "APIC error on CPU%u: %02x(%02x)",
-            smp_processor_id(), v , v1);
     for ( i = 7; i >= 0; --i )
-        if ( v1 & (1 << i) )
-            printk("%s", esr_fields[i]);
-    printk("\n");
+        entries[i] = v1 & (1 << i) ? esr_fields[i] : "";
+    printk(XENLOG_DEBUG
+           "APIC error on CPU%u: %02x(%02x)%s%s%s%s%s%s%s%s\n",
+           smp_processor_id(), v, v1,
+           entries[7], entries[6], entries[5], entries[4],
+           entries[3], entries[2], entries[1], entries[0]);
 }
 
 /*
--
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