[Skiboot] [PATCH] npu2: Use unfiltered mode in XTS tables

Stewart Smith stewart at linux.vnet.ibm.com
Tue Mar 13 15:32:42 AEDT 2018

Reza Arbab <arbab at linux.vnet.ibm.com> writes:
> The XTS_PID context table is limited to 256 possible pids/contexts. To
> relieve this limitation, make use of "unfiltered mode" instead.
> If an entry in the XTS_BDF table has the bit for unfiltered mode set, we
> can just use one context for that entire bdf/lpar, regardless of pid.
> Instead of of searching the XTS_PID table, the NMMU checkout request
> will simply use the entry indexed by lparshort id instead.
> Change opal_npu_init_context() to create these lparshort-indexed
> wildcard entries (0-15) instead of allocating one for each pid. Check
> that multiple calls for the same bdf all specify the same msr value.
> In opal_npu_destroy_context(), continue validating the bdf argument,
> ensuring that it actually maps to an lpar, but no longer remove anything
> from the XTS_PID table. If/when we start supporting virtualized GPUs, we
> might consider actually removing these wildcard entries by keeping a
> refcount, but keep things simple for now.
> Signed-off-by: Reza Arbab <arbab at linux.vnet.ibm.com>
> ---
>  hw/npu2.c           | 73 ++++++++++++++++++++++-------------------------------
>  include/npu2-regs.h |  2 ++
>  2 files changed, 32 insertions(+), 43 deletions(-)

Thanks, merged to master as of 105d80f85b071e1aefefaa4e15beaee027a45fd6

Stewart Smith
OPAL Architect, IBM.

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