[Skiboot-stable] [Skiboot] [PATCH] phb4/5: Escalate page-level TCE kills

[Frederic Barrat]

On 25/08/2021 18:37, Stewart Smith wrote:
> Sounds like also for stable?

I sent it to the stable list but didn't explicitly add the "cc" field in 
the commit log.
Vasant: could you add it or should I resend?

   Fred


> Sent from my iPhone
> 
>> On Aug 25, 2021, at 8:09 AM, Frederic Barrat <fbarrat at linux.ibm.com> wrote:
>>
>> An hw issue was found on P10 (HW560152) where a page-level TCE kill
>> can be dropped if there are enough TCE kill requests already being
>> processed. The net effect is that data integrity is not
>> guaranteed. The circumvention is to stay away from page-level kills
>> and escalate those to PE kills. Which hurts performance.
>> It also affects P9.
>>
>> Signed-off-by: Frederic Barrat <fbarrat at linux.ibm.com>
>> ---
>> hw/phb4.c | 8 ++++++++
>> 1 file changed, 8 insertions(+)
>>
>> diff --git a/hw/phb4.c b/hw/phb4.c
>> index 79083d4a..ddaa18f8 100644
>> --- a/hw/phb4.c
>> +++ b/hw/phb4.c
>> @@ -1051,6 +1051,14 @@ static int64_t phb4_tce_kill(struct phb *phb, uint32_t kill_type,
>>     uint64_t val;
>>     int64_t rc;
>>
>> +    /*
>> +     * HW560152: a page-level kill can be dropped if the
>> +     *     processing queue is backed-up, which can cause data
>> +     *     integrity issues
>> +     */
>> +    if (kill_type == OPAL_PCI_TCE_KILL_PAGES)
>> +        kill_type = OPAL_PCI_TCE_KILL_PE;
>> +
>>     sync();
>>     switch(kill_type) {
>>     case OPAL_PCI_TCE_KILL_PAGES:
>> -- 
>> 2.31.1
>>
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>