Re: [Xen-devel] [PATCH 2/2] Register native mce handler as vMCE bounce back point

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

On Tue, Apr 17, 2012 at 12:55:49PM +0000, Liu, Jinsong wrote:
> Konrad Rzeszutek Wilk wrote:
> > On Mon, Apr 16, 2012 at 01:07:35AM +0000, Liu, Jinsong wrote:
> >>> From 76e40a60878ff72986fd8d92611400195ae0f997 Mon Sep 17 00:00:00
> >>> 2001 
> >> From: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> >> Date: Mon, 16 Apr 2012 00:16:58 +0800
> >> Subject: [PATCH 2/2] Register native mce handler as vMCE bounce back
> >> point 
> >> 
> >> When xen hyeprvisor inject vMCE to guest, use native mce handler to
> >> handle it 
> > 
> > hypervisor
> > 
> >> 
> >> Signed-off-by: Liu, Jinsong <jinsong.liu@xxxxxxxxx>
> >> Signed-off-by: Ke, Liping <liping.ke@xxxxxxxxx>
> >> Signed-off-by: Jiang, Yunhong <yunhong.jiang@xxxxxxxxx>
> >> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
> >>  --- arch/x86/xen/enlighten.c |   10 +++++++---
> >>  1 files changed, 7 insertions(+), 3 deletions(-)
> >> 
> >> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> >> index 15628d4..346ba64 100644
> >> --- a/arch/x86/xen/enlighten.c
> >> +++ b/arch/x86/xen/enlighten.c
> >> @@ -614,8 +614,8 @@ static int cvt_gate_to_trap(int vector, const
> >> gate_desc *val,    /* 
> >>     * Look for known traps using IST, and substitute them
> >>     * appropriately.  The debugger ones are the only ones we care
> >> -   * about.  Xen will handle faults like double_fault and
> >> -   * machine_check, so we should never see them.  Warn if
> >> +   * about.  Xen will handle faults like double_fault,
> >> +   * so we should never see them.  Warn if
> >>     * there's an unexpected IST-using fault handler.        */
> >>    if (addr == (unsigned long)debug)
> >> @@ -630,7 +630,11 @@ static int cvt_gate_to_trap(int vector, const
> >>  gate_desc *val,           return 0; #ifdef CONFIG_X86_MCE
> >>    } else if (addr == (unsigned long)machine_check) { -            return 
> >> 0;
> >> +          /*
> >> +           * when xen hyeprvisor inject vMCE to guest,
> >> +           * use native mce handler to handle it
> >> +           */
> >> +          ;
> > 
> > 
> > Can you just take the check out?
> 
> What do you mean by 'check out'? remove
> else if (addr == (unsigned long) machine_check) {
>       ;
> }
> ?
> 
> That would fail to register mce bounce back point.

Right, b/c right after we hit this check:
  /* Some other trap using IST? */
 639                 if (WARN_ON(val->ist != 0))
 640                         return 0;
 641         }

.. And the val->ist is not set for MCEs right?

> 
> > 
> > 
> >>  #endif
> >>    } else {
> >>            /* Some other trap using IST? */
> >> --
> >> 1.7.1
> 
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