[PATCH] powerpc/eeh: Avoid to handle EEH on a passed Child PE

[Wei Yang]

On Mon, Sep 21, 2015 at 09:49:45PM +1000, Gavin Shan wrote:
>On Mon, Sep 21, 2015 at 05:29:48PM +0800, Wei Yang wrote:
>>Current EEH infrastructure would avoid to handle EEH when a PE is passed to
>>guest, while if this PE is a Child PE of the one hit EEH, host would handle
>>this. By doing so, this would leads to guest hang. The correct way is
>>avoid to handle it on host and let guest to recover.
>>
>>This patch avoids to handle EEH on a passed Child PE.
>>
>
>Ok. It's fixing the problem the guest, which owns a VF, when its PF hitting
>EEH error, right? If so, I'm not sure if you really tested this code. Does
>it work for you?

Yes, I inject error on Parent Bus PE.

>
>When the parent PE (PF) is stopped for EEH recovery, it sounds impossible
>that the child PE can't be affected and just escape from the error. The
>question is how the guest can continue to work after the EEH recovery on
>parent PE?

What I see is the PF is covering and VF in guest is recovering.

>
>>Signed-off-by: Wei Yang <weiyang at linux.vnet.ibm.com>
>>---
>> arch/powerpc/kernel/eeh_pe.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>>diff --git a/arch/powerpc/kernel/eeh_pe.c b/arch/powerpc/kernel/eeh_pe.c
>>index 5cde950..c6d0e9f 100644
>>--- a/arch/powerpc/kernel/eeh_pe.c
>>+++ b/arch/powerpc/kernel/eeh_pe.c
>>@@ -172,6 +172,7 @@ static struct eeh_pe *eeh_pe_next(struct eeh_pe *pe,
>>  * callback returns something other than NULL, or no more PEs
>>  * to be traversed.
>>  */
>>+static void *__eeh_pe_get(void *data, void *flag);
>> void *eeh_pe_traverse(struct eeh_pe *root,
>> 		      eeh_traverse_func fn, void *flag)
>> {
>>@@ -179,6 +180,8 @@ void *eeh_pe_traverse(struct eeh_pe *root,
>> 	void *ret;
>>
>> 	for (pe = root; pe; pe = eeh_pe_next(pe, root)) {
>>+		if (eeh_pe_passed(pe) && (fn != __eeh_pe_get))
>>+			continue;
>
>The code change here seems ugly.
>
>The "flag" can be extended to carry the information to skip pass-through
>PEs or not. So the function calling eeh_pe_traverse() decides to skip
>pass-through PEs or not.

I don't get the point, which "flag" you mean? Add a flag in eeh_pe?

>
>> 		ret = fn(pe, flag);
>> 		if (ret) return ret;
>> 	}
>>@@ -210,6 +213,8 @@ void *eeh_pe_dev_traverse(struct eeh_pe *root,
>
>>
>> 	/* Traverse root PE */
>> 	for (pe = root; pe; pe = eeh_pe_next(pe, root)) {
>>+		if (eeh_pe_passed(pe))
>>+			continue;
>> 		eeh_pe_for_each_dev(pe, edev, tmp) {
>> 			ret = fn(edev, flag);
>> 			if (ret)
>>-- 
>>2.5.0
>>

-- 
Richard Yang
Help you, Help me