[Xen-devel] [PATCH] mce_cleanup

["Liu, Jinsong" <jinsong.liu@xxxxxxxxx>]

X86: mce cleanup for both Intel and AMD mce logic

c/s 22964 fixed a mce memory leaks bug which may trigger xen crash when cpu 
online.
However, there are 2 mce memory leaks: 1 at mce level (arch independent), 1 at 
mce_intel level (arch dependent).
At c/s 22964, it free both leaks at mce_intel level, which would has problem 
under AMD arch.

This patch fix this issue. 
It alloc/free poll_bankmask (arch independent) at mce level, 
and add a notifier block at mce level to avoid xmalloc risk when irq disable. 
With this patch, both Intel and AMD mce works OK in a clean way.

Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>

diff -r 84bacd800bf8 xen/arch/x86/cpu/mcheck/mce.c
--- a/xen/arch/x86/cpu/mcheck/mce.c     Sat Mar 12 13:20:51 2011 +0000
+++ b/xen/arch/x86/cpu/mcheck/mce.c     Mon Mar 14 18:29:13 2011 +0800
@@ -16,6 +16,7 @@
 #include <xen/event.h>
 #include <xen/guest_access.h>
 #include <xen/hypercall.h> /* for do_mca */
+#include <xen/cpu.h>
 
 #include <asm/processor.h>
 #include <asm/system.h>
@@ -695,14 +696,13 @@ int show_mca_info(int inited, struct cpu
     return 0;
 }
 
-int set_poll_bankmask(struct cpuinfo_x86 *c)
+static void set_poll_bankmask(struct cpuinfo_x86 *c)
 {
     int cpu = smp_processor_id();
     struct mca_banks *mb;
 
-    mb = mcabanks_alloc();
-    if (!mb)
-        return -ENOMEM;
+    mb = per_cpu(poll_bankmask, cpu);
+    BUG_ON(!mb);
 
     if (cmci_support && !mce_disabled) {
         mb->num = per_cpu(no_cmci_banks, cpu)->num;
@@ -714,9 +714,6 @@ int set_poll_bankmask(struct cpuinfo_x86
         if (mce_firstbank(c))
             mcabanks_clear(0, mb);
     }
-    per_cpu(poll_bankmask, cpu) = mb;
-
-    return 0;
 }
 
 /* The perbank ctl/status init is platform specific because of AMD's quirk */
@@ -749,6 +746,51 @@ int mca_cap_init(void)
 
     return mca_allbanks ? 0:-ENOMEM;
 }
+
+static void cpu_poll_bankmask_free(unsigned int cpu)
+{
+    struct mca_banks *mb = per_cpu(poll_bankmask, cpu);
+
+    mcabanks_free(mb);
+}
+
+static int cpu_poll_bankmask_alloc(unsigned int cpu)
+{
+    struct mca_banks *mb;
+
+    mb = mcabanks_alloc();
+    if ( !mb )
+        return -ENOMEM;
+
+    per_cpu(poll_bankmask, cpu) = mb;
+    return 0;
+}
+
+static int cpu_callback(
+    struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+    unsigned int cpu = (unsigned long)hcpu;
+    int rc = 0;
+
+    switch ( action )
+    {
+    case CPU_UP_PREPARE:
+        rc = cpu_poll_bankmask_alloc(cpu);
+        break;
+    case CPU_UP_CANCELED:
+    case CPU_DEAD:
+        cpu_poll_bankmask_free(cpu);
+        break;
+    default:
+        break;
+    }
+
+    return !rc ? NOTIFY_DONE : notifier_from_errno(rc);
+}
+
+static struct notifier_block cpu_nfb = {
+    .notifier_call = cpu_callback
+};
 
 /* This has to be run for each processor */
 void mcheck_init(struct cpuinfo_x86 *c)
@@ -802,6 +844,13 @@ void mcheck_init(struct cpuinfo_x86 *c)
     /* Turn on MCE now */
     set_in_cr4(X86_CR4_MCE);
 
+    if ( smp_processor_id() == 0 )
+    {
+        /* Early MCE initialisation for BSP. */
+        if ( cpu_poll_bankmask_alloc(0) )
+            BUG();
+        register_cpu_notifier(&cpu_nfb);
+    }
     set_poll_bankmask(c);
 
     return;
diff -r 84bacd800bf8 xen/arch/x86/cpu/mcheck/mce_intel.c
--- a/xen/arch/x86/cpu/mcheck/mce_intel.c       Sat Mar 12 13:20:51 2011 +0000
+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c       Mon Mar 14 18:29:13 2011 +0800
@@ -1233,17 +1233,15 @@ static void intel_init_mce(void)
 
 static void cpu_mcabank_free(unsigned int cpu)
 {
-    struct mca_banks *mb1, *mb2, *mb3, *mb4;
+    struct mca_banks *mb1, *mb2, *mb3;
 
     mb1 = per_cpu(mce_clear_banks, cpu);
     mb2 = per_cpu(no_cmci_banks, cpu);
     mb3 = per_cpu(mce_banks_owned, cpu);
-    mb4 = per_cpu(poll_bankmask, cpu);
 
     mcabanks_free(mb1);
     mcabanks_free(mb2);
     mcabanks_free(mb3);
-    mcabanks_free(mb4);
 }
 
 static int cpu_mcabank_alloc(unsigned int cpu)

Attachment: mce_cleanup.patch
Description: mce_cleanup.patch

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