== Progress ==
* [GlobalISel] Add support for integers > 32 bits wide [LLVM-310]
- While looking into this I found and fixed a bug in the generic
part of IRTranslator, which reduced the number of fallbacks on the ARM
test-suite by about 20%
- Currently working on lowering function calls etc for 64-bit types
* [GlobalISel] Refactor CallLowering [LLVM-568]
- The CallLowering interface really needs a cleanup before I
continue with LLVM-310
- This has been discussed upstream in the past and would benefit all
targets, so I'm going to give it a shot
* SVE2 code reviews
== Plan ==
* More of the same
* Out of office 29 May - 10 June
== Progress ==
* Out of office on Friday (sick)
* [GlobalISel] Better support for small types [LLVM-553]
- Committed upstream
* GlobalISel
- quickfix for a DBG_VALUE-related bug
- code reviews
* SVE code reviews
* Catching up on Connect / EuroLLVM
== Plan ==
* More of the same
* Out of office end of May - beginning of June
[VIRT-343 # ARMv8.5-RNG, Random Number Generator ]
Posted v4, v5, v6. I think this is now ready for merge.
[VIRT-327 # Richard's upstream QEMU work ]
Posted v3 of the CPUNegativeOffset patch set.
Posted v2, v3, and a pull request for the tlb_fill patch set.
Debugged one more fix for Sparc testthreads.
Reposted some long dormant linux-user fixes.
Started reviving the do_syscall split patch set,
since Laurent asked after it.
r~
o 4 days week.
o LLVM
* Machine outliner:
- Fixed LR save issue, when saved into a register.
- Dealing with LR save/restore when outlined region is a
pop{...,PC} tail-call.
- Investigating potential issue with condition flags.
o Misc
* Various meetings and discussions.
[LLVM-158] buildbot maintenance
- Increased timeouts on some libfuzzer tests, aarch64 full bots should
fail less frequently under load.
[LLVM-534] -n -N support in LLD (needed for Linux kernel allyesconfig
CI with LLD on AArch64)
Rewrote using a different approach after upstream comments
[LLVM-122] BTI and PAC support in LLD
Wrote an implementation, it compiles, but completely untested as of today.
(short week: 3 days)
Brief writeup of a pair of talks I attended on Tuesday at the
Cambridge University Computer Lab by some people from Amazon:
Diana Popa talked about Amazon's new "Firecracker" VMM (virtual
machine monitor -- the userspace component that uses the kernel's KVM
APIs to create and control virtual machines; kvmtool and QEMU are both
VMMs). Their use case is the AWS Lambda service, where VMs are
generally fairly short-lived (on the order of hours), startup time
matters a lot, and the VMs typically don't need very much CPU/RAM
resource. Firecracker is written in Rust, and provides a very simple
guest device model (virtio block and network devices), booting a
kernel that knows it is virtualized. It boots the kernel directly,
without running a BIOS. It has a memory footprint of less than 5MB and
a boot time of 125ms. They are currently working on Arm support (they
have it booting, but some bits still need work, eg the VM doesn't get
the right time because there is no RTC device exposed to the guest).
My feeling was that this shows an advantage of the KVM design: the
kernel/userspace split makes it easy to replace the userspace VMM
part with something customised for the task at hand if you don't
need a full-fat all-bells-and-whistles general-purpose solution.
Andreea Florescu talked next, about the "rust-vmm" libraries. This is
a set of open-source Rust crates which are intended to abstract out
some of the common building blocks for VMMs. Firecracker started as a
fork of Google's crosvm project, but since the use-case requirements
for the two projects are markedly different the code diverged fairly
rapidly. rust-vmm is intended to allow the projects to share code for
things like "nice Rust interfaces to the KVM ioctls" and
"implementations of virtio devices". The project is still in quite an
early stage of development -- they have a few crates that have made it
to the "stable, published on crates.io" phase, but most are either in
"being developed" or still just "planned/proposed/discussed". It's
currently Apache-2.0 licensed, but they are planning to dual-license
to Apache-2.0 | 3-BSD because Apache-2.0 isn't GPL-2.0 compatible, and
they have had some interest in being able to experiment with using
these crates with QEMU. (That sounds a bit outlandish but it's
actually something I'm planning to look into myself -- the nice thing
about Rust is that you can potentially incrementally add it to an
existing C codebase without requiring a ground-up rewrite, so allowing
security hardening of the more "risky" parts. This is very definitely
all still just "exploratory prototyping" though.)
Progress:
* just miscellaneous upstream stuff
thanks
-- PMM
* 1 day off (public holiday)
== Progress ==
* FDPIC
- rebased GCC FDPIC patches. Fixing conflict with fstack-protector.
* GCC upstream validation:
- Fixed ST internal validation broken since GCC bumped to version 10.
Still some spurious failures probably caused by NFS. Testing
workarounds.
- reported a couple of regressions
* GCC
- ubsan on bare-metal toolchain: no news.
* Infra
- [stalled] working on adding binutils regression testing to round-robin jobs
== Next ==
FDPIC:
- GCC: fix problems with fstack-protector
UBSAN/bare-metal: look at how to make it easier to use on CPUs that
lack sync primivites (eg cortex-m0)
o 4 days week.
o LLVM
* Machine outliner:
- Identified an issue related to LR saving inside an outlined
chunk, working on a proper fix.
o Misc
* Various meetings and discussions.
