[Xen-devel] [PATCH] X86 MCE: Add more strict sanity check of one SRAR case

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

Jan,

 

I cannot access my remote office desktop today (network maintain), so cannot reply the SRAR patch email we discussed last month.

 

At the last email we basically agree that the SRAR patch itself looks fine, only with 1 concern about ‘guest_mode’ (in fact the SRAR patch itself didn’t involved guest_mode), and the SRAR patch not in xen unstable tree yet.

Currently I still don’t find out an alternative way to solve the guest_mode issue, so in order to be safe I add this patch.

I think although it may be some overkilled, it’s OK to keep it safe here, after all the SRAR case which RIPV = EIPV = 0 occur rarely.

 

Thanks,

Jinsong

 

======================================

 

X86 MCE: Add more strict sanity check of one SRAR case

 

When RIPV = EIPV = 0, it's a little bit tricky. It may be an asynchronic error, currently we have no way to precisely locate whether the error occur at guest or hypervisor.

To avoid handling error in wrong way, we treat it as unrecovered.

 

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

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

 

# HG changeset patch

# Parent e758b1d928e3d663602741ddc7f55461e2187829

 

diff -r e758b1d928e3 xen/arch/x86/cpu/mcheck/mce_intel.c

--- a/xen/arch/x86/cpu/mcheck/mce_intel.c       Sun Oct 30 17:50:53 2011 -0800

+++ b/xen/arch/x86/cpu/mcheck/mce_intel.c       Fri Dec 02 15:16:52 2011 -0800

@@ -367,8 +367,18 @@

         return 0;

 

     gstatus = mca_rdmsr(MSR_IA32_MCG_STATUS);

-    /* Xen is not pre-emptible */

-    if ( !(gstatus & MCG_STATUS_RIPV) && !guest_mode(regs))

+

+    /*

+     * FIXME: When RIPV = EIPV = 0, it's a little bit tricky. It may be an

+     * asynchronic error, currently we have no way to precisely locate

+     * whether the error occur at guest or hypervisor.

+     * To avoid handling error in wrong way, we treat it as unrecovered.

+     *

+     * Another unrecovered case is RIPV = 0 while in hypervisor

+     * since Xen is not pre-emptible.

+     */

+    if ( !(gstatus & MCG_STATUS_RIPV) &&

+        (!(gstatus & MCG_STATUS_EIPV) || !guest_mode(regs)) )

         return -1;

 

     return mce_action(regs, mctc) == MCER_RESET ? -1 : 0;

 

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