[Skiboot] [PATCH 0/4] OPAL debugfs calls
fbarrat at linux.ibm.com
Tue Nov 24 20:55:53 AEDT 2020
On 05/11/2020 17:15, Cédric Le Goater wrote:
> These patches add a couple of OPAL read/write calls which let the OPAL
> drivers expose any kind of low level information : configuration, HW
> registers, statistics. The write call can perform some reconfiguration.
> I have been using them for a while on P9 and P10 to query XIVE internals,
> time statistics on HW procedures and to modify the allocation of XIVE
> resources for guests. It might be useful to others as debug or bringup
> Last is the quickly-coded generic Linux driver.
> One problem is our snprintf implementation in OPAL which does not
> return the number of bytes that would have been written if the buffer
> was large enough. It would help the Linux driver.
This is interesting. I've played a bit with it with PHBs.
I can imagine it could be useful for debug when cronus is not around.
I'm less convinced about the "write" feature, the interface feels not
precise enough. I guess it's no coincidence that writing ends up being
disabled on all the xive and phb data structures.
A few easy comments on some of the following patches.
> Changes since RFC:
> - introduced a list of opal_debug nodes
> - included PHB debugfs entries
> - removed statistics
> Cédric Le Goater (4):
> core: Add debugfs framework
> phb4: Add debugfs entries for internal tables
> xive/p9: Add debugfs entries for internal tables
> xive/p9: Add debugfs entries for performance
> include/opal-api.h | 4 +-
> include/opal-debug.h | 27 ++++++
> include/xive-p9-regs.h | 14 +++
> core/opal-debug.c | 97 ++++++++++++++++++++
> hw/phb4.c | 118 ++++++++++++------------
> hw/xive.c | 198 +++++++++++++++++++++++++++++++++++++++++
> core/Makefile.inc | 1 +
> 7 files changed, 395 insertions(+), 64 deletions(-)
> create mode 100644 include/opal-debug.h
> create mode 100644 core/opal-debug.c
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