Re: Re: machine check report on HVM startup

[Christoph Egger <Christoph.Egger@amd.com>]

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On Wednesday 13 August 2008 14:48:04 Keir Fraser wrote:
> On 13/8/08 13:40, "Christoph Egger" <Christoph.Egger@amd.com> wrote:
> >>>> This looks to me, there's a non-public event channel using the same
> >>>> number as VIRQ_MCA which fires when  launching memtest as HVM guest.
> >>>
> >>> I don't think this is the case. Sounds easy to repro this issue though.
> >>> I'll give it a go.
> >>
> >> I can boot a memtest-3.4 ISO in an HVM guest on PAE hypervisor just
> >> fine.
> >
> > Does your Dom0 kernel registrate the machine check event handler ?
> > If not, then it things go fine. If yes, then you should see the flood of
> > VIRQ_MCA events in the Dom0.
>
> How do I make it do that?

Assuming you use Linux as Dom0, apply the attached patch to your local tree.
With it, you should see a flood of "xen_mca: HW reported correctable error(s)"
Dom0 kernel messages.

Note, the patch is not intended to go upstream. There will be something better
in the future.

Christoph

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Operating System Research Center

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diff -r c110692c140f arch/i386/kernel/cpu/mcheck/non-fatal.c
--- a/arch/i386/kernel/cpu/mcheck/non-fatal.c	Wed Aug 13 10:00:09 2008 +0100
+++ b/arch/i386/kernel/cpu/mcheck/non-fatal.c	Wed Aug 13 15:10:47 2008 +0200
@@ -60,9 +60,31 @@ static void mce_work_fn(void *data)
 	schedule_delayed_work(&mce_work, MCE_RATE);
 } 
 
+/* Privileged receive callback and transmit kicker. */
+static irqreturn_t xenmca_event(int irq, void *dev_id,
+                                struct pt_regs *regs)
+{
+	printk("xen_mca: HW reported correctable error(s)\n");
+
+        return IRQ_HANDLED;
+}
+
+static int mca_event_irq;
+
 static int __init init_nonfatal_mce_checker(void)
 {
 	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+        if (is_initial_xendomain()) {
+                mca_event_irq = bind_virq_to_irqhandler(
+                        VIRQ_MCA,
+                        0,
+                        xenmca_event,
+                        0,
+                        "mca0",
+                        NULL);
+                BUG_ON(mca_event_irq < 0);
+        }
 
 	/* Check for MCE support */
 	if (!cpu_has(c, X86_FEATURE_MCE))

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