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.. _skiboot-6.0.18:
==============
skiboot-6.0.18
==============
skiboot 6.0.18 was released on Wednesday March 6th, 2019. It replaces
:ref:`skiboot-6.0.17` as the current stable release in the 6.0.x series.
It is recommended that 6.0.18 be used instead of any previous 6.0.x version
due to the bug fixes it contains.
Over :ref:`skiboot-6.0.17` we have several bug fixes, including important ones
for powercap, ipmi-hiomap and BMC communication driver.
powercap
========
- powercap: occ: Fix the powercapping range allowed for user
OCC provides two limits for minimum powercap. One being hard powercap
minimum which is guaranteed by OCC and the other one is a soft
powercap minimum which is lesser than hard-min and may or may not be
asserted due to various power-thermal reasons. So to allow the users
to access the entire powercap range, this patch exports soft powercap
minimum as the "powercap-min" DT property. And it also adds a new
DT property called "powercap-hard-min" to export the hard-min powercap
limit.
IPMI-HIOMAP
===========
- ipmi-hiomap test case enhancements/fixes.
- libflash/ipmi-hiomap: Enforce message size for empty response
The protocol defines the response to the associated messages as empty
except for the command ID and sequence fields. If the BMC is returning
extra data consider the message malformed.
- libflash/ipmi-hiomap: Remove unused close handling
Issuing a HIOMAP_C_CLOSE is not required by the protocol specification,
rather a close can be implicit in a subsequent
CREATE_{READ,WRITE}_WINDOW request. The implicit close provides an
opportunity to reduce LPC traffic and the implementation takes up that
optimisation, so remove the case from the IPMI callback handler.
- libflash/ipmi-hiomap: Overhaul event handling
Reworking the event handling was inspired by a bug report by Vasant
where the host would get wedged on multiple flash access attempts in the
face of a persistent error state on the BMC-side. The cause of this bug
was the early-exit based on ctx->update, which erronously assumed that
all events had been completely handled in prior calls to
ipmi_hiomap_handle_events(). This is not true if e.g.
HIOMAP_E_DAEMON_READY is clear in the prior calls.
Regardless, there were other correctness and efficiency problems with
the handling strategy:
* Ack-able event state was not restored in the face of errors in the
process of re-establishing protocol state
* It forced needless window restoration with respect to the context in
which ipmi_hiomap_handle_events() was called.
* Tests for HIOMAP_E_DAEMON_READY and HIOMAP_E_FLASH_LOST were redundant
with the overhauled error handling introduced in the previous patch
Fix all of the above issues and add comments to explain the event
handling flow.
Tests for correctness follow later in the series.
- libflash/ipmi-hiomap: Overhaul error handling
The aim is to improve the robustness with respect to absence of the
BMC-side daemon. The current error handling roughly mirrors what was
done for the mailbox implementation, but there's room for improvement.
Errors are split into two classes, those that affect the transport state
and those that affect the window validity. From here, we push the
transport state error checks right to the bottom of the stack, to ensure
the link is known to be in a good state before any message is sent.
Window validity tests remain as they were in the hiomap_window_move()
and ipmi_hiomap_read() functions. Validity tests are not necessary in
the write and erase paths as we will receive an error response from the
BMC when performing a dirty or flush on an invalid window.
Recovery also remains as it was, done on entry to the blocklevel
callbacks. If an error state is encountered in the middle of an
operation no attempt is made to recover it on the spot, instead the
error is returned up the stack and the caller can choose how it wishes
to respond.
- libflash/ipmi-hiomap: Fix leak of msg in callback
BMC communication
=================
- core/ipmi: Add ipmi sync messages to top of the list
In ipmi_queue_msg_sync() path OPAL will wait until it gets response from
BMC. If we do not get response ontime we may endup in kernel hardlockups.
Hence lets add sync messages to top of the queue. This will reduces the
chance of hardlockups.
- hw/bt: Introduce separate list for synchronous messages
BT send logic always sends top of bt message list to BMC. Once BMC reads the
message, it clears the interrupt and bt_idle() becomes true.
bt_add_ipmi_msg_head() adds message to top of the list. If bt message list
is not empty then:
- if bt_idle() is true then we will endup sending message to BMC before
getting response from BMC for inflight message. Looks like on some
BMC implementation this results in message timeout.
- else we endup starting message timer without actually sending message
to BMC.. which is not correct.
This patch introduces separate list to track synchronous messages.
bt_add_ipmi_msg_head() will add messages to tail of this new list. We
will always process this queue before processing normal queue.
Finally this patch introduces new variable (inflight_bt_msg) to track
inflight message. This will point to current inflight message.
- hw/bt: Fix message retry handler
In some corner cases (like BMC reboot), bt_send_and_unlock() starts
message timer, but won't send message to BMC as driver is not free to
send message. bt_expire_old_msg() function enables H2B interrupt without
actually sending message.
This patch fixes above issue.
- ipmi/power: Fix system reboot issue
Kernel makes reboot/shudown OPAL call for reboot/shutdown. Once kernel
gets response from OPAL it runs opal_poll_events() until firmware
handles the request.
On BMC based system, OPAL makes IPMI call (IPMI_CHASSIS_CONTROL) to
initiate system reboot/shutdown. At present OPAL queues IPMI messages
and return SUCESS to Host. If BMC is not ready to accept command (like
BMC reboot), then these message will fail. We have to manually
reboot/shutdown the system using BMC interface.
This patch adds logic to validate message return value. If message failed,
then it will resend the message. At some stage BMC will be ready to accept
message and handles IPMI message.
- hw/bt: Add backend interface to disable ipmi message retry option
During boot OPAL makes IPMI_GET_BT_CAPS call to BMC to get BT interface
capabilities which includes IPMI message max resend count, message
timeout, etc,. Most of the time OPAL gets response from BMC within
specified timeout. In some corner cases (like mboxd daemon reset in BMC,
BMC reboot, etc) OPAL may not get response within timeout period. In
such scenarios, OPAL resends message until max resend count reaches.
OPAL uses synchronous IPMI message (ipmi_queue_msg_sync()) for few
operations like flash read, write, etc. Thread will wait in OPAL until
it gets response from BMC. In some corner cases like BMC reboot, thread
may wait in OPAL for long time (more than 20 seconds) and results in
kernel hardlockup.
This patch introduces new interface to disable message resend option. We
will disable message resend option for synchrous message. This will
greatly reduces kernel hardlock up issues.
This is short term fix. Long term solution is to convert all synchronous
messages to asynhrounous one.
PHB3
====
- hw/phb3/naples: Disable D-states
Putting "Mellanox Technologies MT27700 Family [ConnectX-4] [15b3:1013]"
(more precisely, the second of 2 its PCI functions, no matter in what
order) into the D3 state causes EEH with the "PCT timeout" error.
This has been noticed on garrison machines only and firestones do not
seem to have this issue.
This disables D-states changing for devices on root buses on Naples by
installing a config space access filter (copied from PHB4).
|
