Progress:
* VIRT-65 [QEMU upstream maintainership]
- code review
+ more microbit device models
+ some raspi device model improvements
- sent patches for more Coverity issue fixes
- put together a list of source files still with legacy
non-QOM device models (about 60 files total)
- tagged QEMU 3.1.0 rc0
* VIRT-251 [aarch32 Hyp/running microvisors]
- tracked down a regression affecting L4Re guest: we had
misimplemented HCR.{VI,VF}. Sent patchset reverting the
broken version and implementing the correct semantics.
- finally tracked down why the 32-bit version of L4Re/Fiasco was
crashing -- we were incorrectly implementing Hyp mode as having
a banked r14, but it shares that register with User and System modes.
- These patches fix all the known issues with these guests.
thanks
-- PMM
=== Work done during the past week ===
* Resurrect code size optimization for fmul/dmul from Tony Wang:
+ clean up new testsuite directive andd testcases
* Fix -mslow-flash-data:
+ resurrect / rebase Arm internal patch to fix -mslow-flash-data
once and for all
+ many fixes to make it pass all testsuite with -mslow-flash-data without ICE
* Line management.
=== Plan for week 45 ===
* LLVM-432 (Support arithmetic on FileCheck regex variable):
+ extend testcase coverage (add tests for latest syntax change and
add more negative testing)
+ finish cleaning up the code
* Try to reproduce perf issue mentioned in week #30's weekly report on
latest perf
o Two days off.
o LLVM
* Machine Outliner on ARM prototype:
- catch-up after vacation
- re-based prototype branch on upstream
- Investigating issues in PIC mode
== This Week ==
* PR83750: CSE erf/erfc pair (6/10)
- Submitted patch upstream
* SVE ACLE (2/10)
- Started working on shift intrinsics
* GNU-235 (1/10)
- Cancelled card after I realized vrp does not support floating point ranges -:/
* Misc (1/10)
- Meetings
== Next Week ==
- PR83750: Address upstream comments
- GNU-405: Benchmark patch to provide more evidence to make it acceptable.
- SVE ACLE: Continue work on shift intrinsics.
[VIRT-241 # QEMU ARMv8.3 support ]
Finished filling out the sub-tasks for v8.3. Added some implementation
notes to some of those tasks as I reread the relevant documentation.
[VIRT-246 # ARMv8.1-LOR Limited Ordering Regions ]
Posted a trivial implementation.
[VIRT-247 # ARMv8.1-HPD and ARMv8.2-AA32HPD ]
Posted.
[Upstream]
Dirty tlb patches and decodetree changes squeeked in for softfreeze.
Another round of tlb flush reduction for aa64. This time exposing
asid's to the softmmu core and allowing it to flush when necessary.
Some more work toward moving x86 softmmu load sequences out of line.
The bulk of the code for 32-bit is now written, but it doesn't work yet.
Fix my thinko wrt divdeu and power7.
[GCC]
The cleanup part of my atomics patch set has been approved and committed.
Posted v3 of the out-of-line atomics part as well.
r~
Upstream Work ([VIRT-109])
==========================
- reviewed {Qemu-arm} {RFC v4 00/71} per-CPU locks Message-Id:
<20181025151103.GA19931@flamenco>
- this is a precursor to Emilio's {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
QEMU Tooling ([VIRT-252])
=========================
[VIRT-252] https://projects.linaro.org/browse/VIRT-252
QEMU plugin support ([VIRT-280])
- go through Emilio's {RFC 00/48} Plugin support Message-Id:
<20181025172057.20414-1-cota(a)braap.org> :todo
- port my example tools to his framework
[VIRT-280] https://projects.linaro.org/browse/VIRT-280
Kernel Debug via gdbstub
- started re-spin of [KVM/QEMU guest debug fix]
- reviewed/tested problem fixed by {Qemu-devel} {PATCH 0/5}
target/arm: KVM vs ARMISARegisters Message-Id:
<20181024113709.16599-1-richard.henderson(a)linaro.org>
- found a weird bug w.r.t single-stepping first instruction
- started down the debugging rabbit hole
[KVM/QEMU guest debug fix]
https://github.com/stsquad/qemu/tree/kvm/fix-breakpoints-v2
Other Tasks
===========
- Wrote up [KVM Forum 2018 report]
- started looking at {RFC PATCH v2 00/23} KVM: arm64: Initial support
for SVE guests Message-Id:
<1538141967-15375-1-git-send-email-Dave.Martin(a)arm.com>
[KVM Forum 2018 report]
https://collaborate.linaro.org/display/CR/20181024+KVM+Forum+2018
Completed Reviews [2/2]
=======================
{PATCH v2 0/3} Modern shell scripting (use $() instead of ``)
Message-Id: <20181018031723.23459-1-maozhongyi(a)cmss.chinamobile.com>
- CLOSING NOTE [2018-10-31 Wed 15:37]
The bit that touched bootstrap was fine
{Qemu-arm} {RFC v4 00/71} per-CPU locks
Message-Id: <20181025151103.GA19931@flamenco>
- CLOSING NOTE [2018-10-31 Wed 16:58]
Looks good, needs a minor tweak for linux-user mode. Will check
final patches on the next iteration.
Absences
========
- Christmas Holidays
- Connect BKK19 (1-5th April 2019)
Current Review Queue
====================
* {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
* {RFC PATCH v2 00/23} KVM: arm64: Initial support for SVE guests
Message-Id: <1538141967-15375-1-git-send-email-Dave.Martin(a)arm.com>
* {PATCH 0/7} Acceptance Tests: basic architecture support
Message-Id: <20181004151429.7232-1-crosa(a)redhat.com>
* {PATCH v7 00/19} Fixing record/replay and adding reverse debugging
Message-Id: <20181010133333.24538.53169.stgit@pasha-VirtualBox>
* {PATCH v2 0/3} Bootstrap Python venv and acceptance/functional tests
Message-Id: <20181009041826.19462-1-crosa(a)redhat.com>
* {Qemu-arm} {PATCH 00/13} target/arm: Implement v8M stack limit checks
Message-Id: <20181002163556.10279-1-peter.maydell(a)linaro.org>
--
Alex Bennée
Progress:
* VIRT-65 [QEMU upstream maintainership]
- code review
- target-arm pull requests
- lots of pull request processing (softfreeze was this week)
- investigated and sent patches to fix a bug where a PC related
pullrequest was failing tests on my merge test setup (turned
out to be a build system issue where we were doing things in
configure that meant make didn't notice it needed to rerun it)
- some simple patches for coverity issues
thanks
-- PMM
[LLVM-203] Code-Size investigation with PGO
- Finished up the remain tasks and resolved the ticket.
- Tidied up the patches and added tests so that I can potentially
share them with other interested parties.
-- Writing tests took a lot longer than I thought as it involves
faking a profile and there were quite a few caveats to doing that.
Some prototyping in LLVM and LLD for some internal ABI discussions.
* 1 day off
== Progress ==
* FDPIC
- Cortex-M fix for binutils committed. uClibc-ng patch on-going
- GCC: handling feedback on v3 patches.
Trying to build/check xtensa uclinux toolchain to check my patches
do not affect it. No satisfactory reference build yet.
* GCC upstream validation:
- reported a few regressions
- one of last week's regressions is causing timeouts on some
validations, thus delaying the full queue. I haven't isolated the
cause yet
- dealing with some random results, again
* GCC:
- bug report on aarch64 about misaligned accesses. Waiting for more
details to reproduce the problem.
* misc (conf-calls, meetings, emails, ....)
- Benchmarking harness hopefully fixed
- reviewing infra script patches
- bugzilla cleanup
== Next ==
FDPIC:
- GCC: followup v3 patches
- uclibc-ng: look at how to test fdpic mode with openadk
- use qemu-system mode to run more tests
Benchmarking:
- fix harness until they support gcc-8
=== Work done during this past week ===
* GNU-296 / GCC PR85434 / CVE-2018-12886: upstream review
+ avoid useless cmp after eors
+ fix another missing earlyclobber
+ full Thumb-1, Thumb-2 and Arm bootstrap with testing with and
without -fPIC, with and without -fstack-protector-all
* Continue patch to further update cpus and architectures in bfd:
external review
+ also teach GAS about Armv5TEJ and newer wrt. bfd architectures tags
+ fix ld action in run_dump_test
+ add testing for all this and submit for external review
* Resurrect code size optimization for fmul/dmul from Tony Wang:
+ rebase on trunk
* Line management
=== Plan for week 43 ===
* LLVM-432 (Support arithmetic on FileCheck regex variable):
+ extend testcase coverage (add tests for latest syntax change and
add more negative testing)
+ finish cleaning up the code
* Try to reproduce perf issue mentioned in week #30's weekly report on
latest perf
* Line management
Progress:
* Attended OSS Europe/KVM Forum
- as usual, a good week (helpful conversations, interesting sessions)
- full conference writeup later in the week
thanks
-- PMM
[VIRT-198 # QEMU: SVE Emulation Support ]
Last of the patches merged to mainline. Epic is now closed.
[VIRT-282 # QEMU: Accelerate TCG with KVM ]
A hallway talk with Paolo lead to a write-up, and Alex encouraged me to create
the epic. The epic description contains a link to the write-up, if anyone is
interested. I'd like to at least create a vm, measure some round-trip costs,
and properly gauge the level of difficulty. Beyond that... we'll see.
[Upstream]
Patch review:
- risc-v decodetree patches v2.
Produced some patches against decodetree itself in response.
I'm hopeful to see a much cleaner v3.
- per-cpu locks
[KVM Forum]
- Unsurprisingly, lots of people worked on speculation mitigation this year.
- Lots of focus on "ram", and the allocation and management thereof.
- Four talks on improving nested virtualization.
- The rest to follow in the trip report.
r~
== Progress ==
* FDPIC
- Posted binutils and uClibc-ng patches to fix cortex-M support, under
discussion
- GCC: handling feedback on v3 patches.
Experimented thumb-1 builds, failed.
* GCC upstream validation:
- reported a few regressions
- dealing with some random results, again
* GCC:
- bug report on aarch64 about misaligned accesses. Waiting for more
details to reproduce the problem.
* misc (conf-calls, meetings, emails, ....)
- Working on fixes of our benchmarking harness to support new gcc-8 releases.
== Next ==
FDPIC:
- GCC: followup v3 patches
- uclibc-ng: look at how to test fdpic mode with openadk
- use qemu-system mode to run more tests
Benchmarking:
- fix harness until they support gcc-8
== This Week ==
* GNU-405: Implement division using vrecpe / vrecps (4/10)
- Patch validated and posted upstream.
* SVE ACLE intrinsics (4/10)
- Going thru documentation.
* GNU-235: Provide value-range info for erf family of functions (1/10)
- Working on patch.
* Misc (1/10)
- Meetings
== Next Week ==
- Continue GNU-235, SVE ACLE intrinsics
Upstream Work ([VIRT-109])
==========================
- started looking at {Qemu-arm} {RFC v4 00/71} per-CPU locks
Message-Id: <20181025151103.GA19931@flamenco>
- this is a precursor to Emilio's {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
[VIRT-109] https://projects.linaro.org/browse/VIRT-109
Other Tasks
===========
- Attended KVM Forum 2018
- I am now Spectre'd out ;-)
- Some interesting discussions on upstream CI
- will save the rest of my notes for the conference report
- Delivered QEMU Keynote/Status report @ KVM Forum 2018
- Here are [the slides]
[the slides]
http://people.linaro.org/~alex.bennee/org/presentations/kvm18-qemu-keynote.…
Current Review Queue
====================
* {Qemu-arm} {RFC v4 00/71} per-CPU locks
Message-Id: <20181025151103.GA19931@flamenco>
* {RFC 00/48} Plugin support
Message-Id: <20181025172057.20414-1-cota(a)braap.org>
* {PATCH v2 0/3} Modern shell scripting (use $() instead of ``)
Message-Id: <20181018031723.23459-1-maozhongyi(a)cmss.chinamobile.com>
* {PATCH 0/7} Acceptance Tests: basic architecture support
Message-Id: <20181004151429.7232-1-crosa(a)redhat.com>
* {PATCH v7 00/19} Fixing record/replay and adding reverse debugging
Message-Id: <20181010133333.24538.53169.stgit@pasha-VirtualBox>
* {PATCH v2 0/3} Bootstrap Python venv and acceptance/functional tests
Message-Id: <20181009041826.19462-1-crosa(a)redhat.com>
--
Alex Bennée
[LLVM-203] Investigation into profiling and code-size optimizations
- Collected the remaining data I needed over the weekend.
- Wrote up report
- Rebased patches on tip of trunk
- Attached results and report to Jira issue.
- A one line summary of the results is that if you are lucky you can
get close to peak performance at close to Os code size if your program
happens to spend most of its time in a few small places. If you are
unlucky then increased inlining and unrolling can still result in an
overall code size increase over -O3 but the effect will be limited.
[LLVM-158] Monitor and maintain buildbots
- Relatively quiet week, a couple of patches pinged for fixes/reverts.
== This Week ==
* TCWG-1234: Coremark regression (7/10)
- Fixed golang regressions with the patch.
- Posted patch upstream to change hoisting order and apply cost model.
* Public holiday (2/10)
* Misc (1/10)
- Meetings
== Next Week ==
- TCWG-319, SVE
[VIRT-214 # SVE System Registers ]
v4 posted and merged to target-arm.next; will be in master shortly.
That will complete basic SVE system mode support.
[UPSTREAM]
tcg-next patches collected and flushed.
Dug into apparently excessive overhead in aarch64 guest tlb flushing, noticed
by chance while doing something else. Two patches upstream, several more
written but need cleanup. Total overhead down from 25% to 9%.
r~
=== Work done during this past week ===
* GNU-296 / GCC PR85434 / CVE-2018-12886:
+ few more issues fixed and associated testing
+ now also running Thumb-1 bootstrap and testing
* Prepare patch to further update cpus and architectures in bfd
* Line management
=== Plan for week 43 ===
* GNU-296 / GCC PR85434 / CVE-2018-12886:
+ finish testing, and submit new stack protector patch for upstream review
* LLVM-432 (Support arithmetic on FileCheck regex variable):
+ extend testcase coverage (add tests for latest syntax change and
add more negative testing)
+ finish cleaning up the code
* Try to reproduce perf issue mentioned in week #30's weekly report on
latest perf
* Line management
Progress:
* VIRT-65 [QEMU upstream maintainership]
- code review
- use ID registers as master source for "should this CPU
have this feature" information (rth)
- clean up 32-bit Neon to use vector infrastructure (rth)
- don't let the kernel get loaded on top of our builtin
bootloader if it happens to ask for a zero text offset
- Xilinx Versal board patches
- target-arm pull requests
- some minor patches to fix new clang warnings
- preparation for KVM Forum/QEMU Summit etc next week
thanks
-- PMM
== Progress ==
* FDPIC
- GCC: handled feedback on v3 patches.
Not much info on how to test other existing uclinux targets.
Noticed that GCC trunk build fails when targeting cortex-m23
(v8-m.baseline), problems in support libs (libgcc, newlib)
* GCC upstream validation:
- reported a few regressions
- dealing with some random results, again
* GCC:
- bug report on aarch64 about misaligned accesses. Waiting for more
details to reproduce the problem.
* misc (conf-calls, meetings, emails, ....)
== Next ==
FDPIC:
- GCC: discuss v3 patches where the way forward is not clear yet
- uclibc-ng: look at how to test fdpic mode with openadk
- use qemu-system mode to run more tests
[LLVM-203] (was TCWG-1424, we've moved issues to a new project)
Started writing up results to close out this investigation.
- Reran some sample profiling test cases with a higher sample rate.
- Investigated why some test cases exploded in code-size with LTO.
- Got some results for thin LTO (broadly similar to LTO).
- Discovered that I need to pass in extra linker options to enable LTO
to use the new pass manager, sample profiling and setting of
optimisation level.
-- Need to rerun these configurations over the weekend.
- Have most of the surrounding text of the report written, now need to
work on presentation of results.
[TCWG-1473] Fix big-endian linux kernel builds for AArch32
Now committed upstream
Holiday Friday
