Re: [PATCH v11 00/31] LoongArch64 port of QEMU TCG

[Richard Henderson <richard.henderson@linaro.org>]

On 12/20/21 9:40 PM, WANG Xuerui wrote:
> Hi all,
> 
> This is a port of QEMU TCG to the brand-new CPU architecture LoongArch,
> introduced by Loongson with their 3A5000 chips.
> 
> Everything is tested on real 3A5000 board (system emulation, linux-user,
> make check) and GitLab (CI jobs), and rebased to latest master branch.
> 
> ## About the series
> 
> Only the LP64D ABI is supported, as this is the only one fully
> implemented and supported by Loongson so far. 32-bit support is incomplete
> from outset, and removed from the very latest upstream submissions, so you
> can't even configure for that.
> 
> The architecture's documentation is already translated into English;
> it can be browsed at https://loongson.github.io/LoongArch-Documentation/.
> The LoongArch ELF psABI doc (version 1.00) could be found at [1];
> if anything is missing there, it's most likely the same as RISC-V, but
> you can always raise an issue over their issue tracker at [2].
> 
> [1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html
> [2]: https://github.com/loongson/LoongArch-Documentation/issues
> 
> In this series I made use of generated instruction encodings and
> emitters from https://github.com/loongson-community/loongarch-opcodes
> (a community project started by myself, something I must admit), as the
> LoongArch encoding is highly irregular even for a fixed 32-bit ISA, and
> I want to minimize the maintenance burden for future collaboration.
> 
> This series touches some of the same files as Song Gao's previous
> submission of LoongArch *target* support, which is a bit unfortunate;
> one of us will have to rebase after either series gets in. Actual
> conflict should only happen on build system bits and include/elf.h,
> though, as we're working on entirely different areas.
> 
> ## How to build and test this
> 
> Upstream support for LoongArch is largely WIP for now, which means you
> must apply a lot of patches if you want to even cross-build for this arch.
> The main sources I used are as follows:
> 
> * binutils: (already upstream as of November 2021)
> * gcc: https://github.com/xen0n/gcc/tree/for-gentoo-gcc-12-v5
>    based on https://github.com/loongson/gcc/tree/loongarch_upstream_v3
> * glibc: https://github.com/xen0n/glibc/tree/for-gentoo-glibc-2.34-v3
>    based on https://github.com/loongson/glibc/tree/loongarch_2_34_dev
> * Linux: https://github.com/xen0n/linux/tree/loongarch-playground-v7
>    based on https://github.com/loongson/linux/tree/loongarch-next
> * Gentoo overlay: https://github.com/xen0n/loongson-overlay
> 
> I have made ready-to-use Gentoo stage3 tarballs, but they're served with
> CDN off my personal cloud account, and I don't want the link to be
> exposed so that my bills skyrocket; you can reach me off-list to get the
> links if you're interested.
> 
> As for the hardware availability, the boards can already be bought in
> China on Taobao, and I think some people at Loongson might be able to
> arrange for testing environments, if testing on real hardware other than
> mine is required before merging; they have their in-house Debian spin-off
> from the early days of this architecture. Their kernel is
> ABI-incompatible with the version being upstreamed and used by me, but
> QEMU should work there regardless.
> 
> Lastly, I'm new to QEMU development and this is my first patch series
> here; apologizes if I get anything wrong, and any help or suggestion is
> certainly appreciated!
> 
> ## Changelog
> 
> v11 -> v10:
> 
> - Rebased to latest development branch

Awesome, thanks.  I was just about to ask if you could update for Paolo's meson.build 
changes.  I've tagged the PR for the initial commit, and it'll go in next.


r~