On 25-Mar-26 2:47 AM, Dixit, Ashutosh wrote:
On Sun, 15 Mar 2026 23:41:02 -0700, Satyanarayana K V P wrote:
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V5 -> V6:
- Updated commit message.
- Return number of engines and memory regions as zero instead of returning
query size as zero (Michal Wajdeczko).
- Allow all other query IOCTLs excepts query_engines and query_mem_regions
(Michal Wajdeczko).
Can someone explain the reason to move away from the approach in v5? Afais
v6 has issues of this sort:
The V6 is due to comment from Rodrigo from V5 "
Looking to this patch I got myself wondering if query.size == 0 is
long-term proof... I mean, if we need to get some OA/RAS/telemetry
kind of API that end up needing some kind of query information....
Michals, thoughts on this?
I know, I know, this solution is indeed much better than my
proposal of no ioctl exposed. But I mean, since we are taking
this path and allowing some ioctl. Shouldn't we prepare at least
the query for that and then only limiting the number of engines
and memory regions to zero?"
and comment from you (Dixit, Ashutosh)as well.
"Also, there were some questions about supporting OA in the
admin-only-pf. Here are some high level points about this:
* OA/EUSTALL is not supported in VF's in current products, this might
change in the future
* OA/EUSTALL in admin-only-pf can be used to profile global counts across
VF's
* OA/EUSTALL themselves don't allow workload submission etc. They only
allow reading profiling data from HW
* OA/EUSTALL in admin-only-pf will need the observation ioctl to be
supported. Also, some other query ioctls such as hw configuration,
topology, frequency will be needed to make sense of OA/EUSTALL data."
* query_engines will return 0 engines but query_hwconfig will return > 0
engines
* query_engines will return 0 engines but query_oa_units will list out the
engines
* query_oa_units will return valid oa support but observation ioctl will
fail
v5 seems to have avoided contradictions of this sort. Or this doesn't
matter? Thanks.
Since we are not exposing any other IOCTLs, even if query_hwconfig and
query_oa_units find number of engines > 0, the UMD can't submit any WL. So, should be
fine right.
