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author | Vasant Hegde <hegdevasant@linux.vnet.ibm.com> | 2019-06-30 17:07:27 +0530 |
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committer | Stewart Smith <stewart@linux.ibm.com> | 2019-07-02 08:40:31 +1000 |
commit | 197ee04e276b87c2546acee643a934f5da31c535 (patch) | |
tree | 95b1fa2c719ddfb9988c347dbd5f192559e15993 /doc | |
parent | 695240b0cadd29170a14c9c76048ab1192a70edf (diff) | |
download | skiboot-197ee04e276b87c2546acee643a934f5da31c535.zip skiboot-197ee04e276b87c2546acee643a934f5da31c535.tar.gz skiboot-197ee04e276b87c2546acee643a934f5da31c535.tar.bz2 |
skiboot v6.3.2 release notes
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
(cherry picked from commit 7a2b63d5457345c7dd8b6d7d9524b58a0aa0ae5e)
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/release-notes/skiboot-6.3.2.rst | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/doc/release-notes/skiboot-6.3.2.rst b/doc/release-notes/skiboot-6.3.2.rst new file mode 100644 index 0000000..0282fc7 --- /dev/null +++ b/doc/release-notes/skiboot-6.3.2.rst @@ -0,0 +1,219 @@ +.. _skiboot-6.3.2: + +============== +skiboot-6.3.2 +============== + +skiboot 6.3.2 was released on Monday July 1st, 2019. It replaces +:ref:`skiboot-6.3.1` as the current stable release in the 6.3.x series. + +It is recommended that 6.3.2 be used instead of 6.3.1 version due to the +bug fixes it contains. + +Bug fixes included in this release are: + +- npu2: Purge cache when resetting a GPU + + After putting all a GPU's links in reset, do a cache purge in case we + have CPU cache lines belonging to the now-unaccessible GPU memory. + +- npu2: Reset NVLinks when resetting a GPU + + Resetting a V100 GPU brings its NVLinks down and if an NPU tries using + those, an HMI occurs. We were lucky not to observe this as the bare metal + does not normally reset a GPU and when passed through, GPUs are usually + before NPUs in QEMU command line or Libvirt XML and because of that NPUs + are naturally reset first. However simple change of the device order + brings HMIs. + + This defines a bus control filter for a PCI slot with a GPU with NVLinks + so when the host system issues secondary bus reset to the slot, it resets + associated NVLinks. + +- hw/phb4: Assert Link Disable bit after ETU init + + The cursed RAID card in ozrom1 has a bug where it ignores PERST being + asserted. The PCIe Base spec is a little vague about what happens + while PERST is asserted, but it does clearly specify that when + PERST is de-asserted the Link Training and Status State Machine + (LTSSM) of a device should return to the initial state (Detect) + defined in the spec and the link training process should restart. + + This bug was worked around in 9078f8268922 ("phb4: Delay training till + after PERST is deasserted") by setting the link disable bit at the + start of the FRESET process and clearing it after PERST was + de-asserted. Although this fixed the bug, the patch offered no + explaination of why the fix worked. + + In b8b4c79d4419 ("hw/phb4: Factor out PERST control") the link disable + workaround was moved into phb4_assert_perst(). This is called + always in the CRESET case, but a following patch resulted in + assert_perst() not being called if phb4_freset() was entered following a + CRESET since p->skip_perst was set in the CRESET handler. This is bad + since a side-effect of the CRESET is that the Link Disable bit is + cleared. + + This, combined with the RAID card ignoring PERST results in the PCIe + link being trained by the PHB while we're waiting out the 100ms + ETU reset time. If we hack skiboot to print a DLP trace after returning + from phb4_hw_init() we get: :: + + PHB#0001[0:1]: Initialization complete + PHB#0001[0:1]: TRACE:0x0000102101000000 0ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000001101000000 23ms GEN1:x16:detect + PHB#0001[0:1]: TRACE:0x0000102101000000 23ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000183101000000 29ms training GEN1:x16:config + PHB#0001[0:1]: TRACE:0x00001c5881000000 30ms training GEN1:x08:recovery + PHB#0001[0:1]: TRACE:0x00001c5883000000 30ms training GEN3:x08:recovery + PHB#0001[0:1]: TRACE:0x0000144883000000 33ms presence GEN3:x08:L0 + PHB#0001[0:1]: TRACE:0x0000154883000000 33ms trained GEN3:x08:L0 + PHB#0001[0:1]: CRESET: wait_time = 100 + PHB#0001[0:1]: FRESET: Starts + PHB#0001[0:1]: FRESET: Prepare for link down + PHB#0001[0:1]: FRESET: Assert skipped + PHB#0001[0:1]: FRESET: Deassert + PHB#0001[0:1]: TRACE:0x0000154883000000 0ms trained GEN3:x08:L0 + PHB#0001[0:1]: TRACE: Reached target state + PHB#0001[0:1]: LINK: Start polling + PHB#0001[0:1]: LINK: Electrical link detected + PHB#0001[0:1]: LINK: Link is up + PHB#0001[0:1]: LINK: Went down waiting for stabilty + PHB#0001[0:1]: LINK: DLP train control: 0x0000105101000000 + PHB#0001[0:1]: CRESET: Starts + + What has happened here is that the link is trained to 8x Gen3 33ms after + we return from phb4_init_hw(), and before we've waitined to 100ms + that we normally wait after re-initialising the ETU. When we "deassert" + PERST later on in the FRESET handler the link in L0 (normal) state. At + this point we try to read from the Vendor/Device ID register to verify + that the link is stable and immediately get a PHB fence due to a PCIe + Completion Timeout. Skiboot attempts to recover by doing another CRESET, + but this will encounter the same issue. + + This patch fixes the problem by setting the Link Disable bit (by calling + phb4_assert_perst()) immediately after we return from phb4_init_hw(). + This prevents the link from being trained while PERST is asserted which + seems to avoid the Completion Timeout. With the patch applied we get: :: + + PHB#0001[0:1]: Initialization complete + PHB#0001[0:1]: TRACE:0x0000102101000000 0ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000001101000000 23ms GEN1:x16:detect + PHB#0001[0:1]: TRACE:0x0000102101000000 23ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000909101000000 29ms presence GEN1:x16:disabled + PHB#0001[0:1]: CRESET: wait_time = 100 + PHB#0001[0:1]: FRESET: Starts + PHB#0001[0:1]: FRESET: Prepare for link down + PHB#0001[0:1]: FRESET: Assert skipped + PHB#0001[0:1]: FRESET: Deassert + PHB#0001[0:1]: TRACE:0x0000001101000000 0ms GEN1:x16:detect + PHB#0001[0:1]: TRACE:0x0000102101000000 0ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000001101000000 24ms GEN1:x16:detect + PHB#0001[0:1]: TRACE:0x0000102101000000 36ms presence GEN1:x16:polling + PHB#0001[0:1]: TRACE:0x0000183101000000 97ms training GEN1:x16:config + PHB#0001[0:1]: TRACE:0x00001c5881000000 97ms training GEN1:x08:recovery + PHB#0001[0:1]: TRACE:0x00001c5883000000 97ms training GEN3:x08:recovery + PHB#0001[0:1]: TRACE:0x0000144883000000 99ms presence GEN3:x08:L0 + PHB#0001[0:1]: TRACE: Reached target state + PHB#0001[0:1]: LINK: Start polling + PHB#0001[0:1]: LINK: Electrical link detected + PHB#0001[0:1]: LINK: Link is up + PHB#0001[0:1]: LINK: Link is stable + PHB#0001[0:1]: LINK: Card [9005:028c] Optimal Retry:disabled + PHB#0001[0:1]: LINK: Speed Train:GEN3 PHB:GEN4 DEV:GEN3 + PHB#0001[0:1]: LINK: Width Train:x08 PHB:x08 DEV:x08 + PHB#0001[0:1]: LINK: RX Errors Now:0 Max:8 Lane:0x0000 + +- npu2: Reset PID wildcard and refcounter when mapped to LPID + + Since 105d80f85b "npu2: Use unfiltered mode in XTS tables" we do not + register every PID in the XTS table so the table has one entry per LPID. + Then we added a reference counter to keep track of the entry use when + switching GPU between the host and guest systems (the "Fixes:" tag below). + + The POWERNV platform setup creates such entries and references them + at the boot time when initializing IOMMUs and only removes it when + a GPU is passed through to a guest. This creates a problem as POWERNV + boots via kexec and no defererencing happens; the XTS table state remains + undefined. So when the host kernel boots, skiboot thinks there are valid + XTS entries and does not update the XTS table which breaks ATS. + + This adds the reference counter and the XTS entry reset when a GPU is + assigned to LPID and we cannot rely on the kernel to clean that up. + +- hw/phb4: Use read/write_reg in assert_perst + + While the PHB is fenced we can't use the MMIO interface to access PHB + registers. While processing a complete reset we inject a PHB fence to + isolate the PHB from the rest of the system because the PHB won't + respond to MMIOs from the rest of the system while being reset. + + We assert PERST after the fence has been erected which requires us to + use the XSCOM indirect interface to access the PHB registers rather than + the MMIO interface. Previously we did that when asserting PERST in the + CRESET path. However in b8b4c79d4419 ("hw/phb4: Factor out PERST + control"). This was re-written to use the raw in_be64() accessor. This + means that CRESET would not be asserted in the reset path. On some + Mellanox cards this would prevent them from re-loading their firmware + when the system was fast-reset. + + This patch fixes the problem by replacing the raw {in|out}_be64() + accessors with the phb4_{read|write}_reg() functions. + +- opal-prd: Fix prd message size issue + + If prd messages size is insufficient then read_prd_msg() call fails with + below error. And caller is not reallocating sufficient buffer. Also its + hard to guess the size. + + sample log::: + ----------- + Mar 28 03:31:43 zz24p1 opal-prd: FW: error reading from firmware: alloc 32 rc -1: Invalid argument + Mar 28 03:31:43 zz24p1 opal-prd: FW: error reading from firmware: alloc 32 rc -1: Invalid argument + Mar 28 03:31:43 zz24p1 opal-prd: FW: error reading from firmware: alloc 32 rc -1: Invalid argument + .... + + Lets use opal-msg-size device tree property to allocate memory + for prd message. + +- npu2: Fix clearing the FIR bits + + FIR registers are SCOM-only so they cannot be accesses with the indirect + write, and yet we use SCOM-based addresses for these; fix this. + +- opal-gard: Account for ECC size when clearing partition + + When 'opal-gard clear all' is run, it works by erasing the GUARD then + using blockevel_smart_write() to write nothing to the partition. This + second write call is needed because we rely on libflash to set the ECC + bits appropriately when the partition contained ECCed data. + + The API for this is a little odd with the caller specifying how much + actual data to write, and libflash writing size + size/8 bytes + since there is one additional ECC byte for every eight bytes of data. + + We currently do not account for the extra space consumed by the ECC data + in reset_partition() which is used to handle the 'clear all' command. + Which results in the paritition following the GUARD partition being + partially overwritten when the command is used. This patch fixes the + problem by reducing the length we would normally write by the number + of ECC bytes required. + +- nvram: Flag dangerous NVRAM options + + Most nvram options used by skiboot are just for debug or testing for + regressions. They should never be used long term. + + We've hit a number of issues in testing and the field where nvram + options have been set "temporarily" but haven't been properly cleared + after, resulting in crashes or real bugs being masked. + + This patch marks most nvram options used by skiboot as dangerous and + prints a chicken to remind users of the problem. + +- devicetree: Don't set path to dtc in makefile + + By setting the path we fail to build under buildroot which has it's own + set of host tools in PATH, but not at /usr/bin. + + Keep the variable so it can be set if need be but default to whatever + 'dtc' is in the users path. |