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

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Date:	Tue, 17 Apr 2012 14:18:56 -0400
From:	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
To:	"Liu, Jinsong" <jinsong.liu@...el.com>
Cc:	"xen-devel@...ts.xensource.com" <xen-devel@...ts.xensource.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] Register native mce handler as vMCE bounce back point

On Tue, Apr 17, 2012 at 05:06:49PM +0000, Liu, Jinsong wrote:
> Konrad Rzeszutek Wilk wrote:
> > 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@...el.com>
> >>>> 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@...el.com>
> >>>> Signed-off-by: Ke, Liping <liping.ke@...el.com>
> >>>> Signed-off-by: Jiang, Yunhong <yunhong.jiang@...el.com>
> >>>> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
> >>>>  --- 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?
> 
> No, mce ist is set as 0/5 (32/64), set_intr_gate_ist(X86_TRAP_MC, &machine_check, MCE_STACK); 

OK. then your idea is the right one. Please just fix the spelling and
re-submit.

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