FEX-Emu 2308 Continues Striving To Be "The Greatest x86/x86-64 Emulator On Linux"

[coder]

Let's get over these lists. The TSO memory model is not only implemented by Apple SoCs, Nvidia Denver/Carmel and Fujitsu A64fx implements this mode too. But the Denver/Carmel are less relevant today(too old) and the Fujitsu A64fx is an HPC oriented SoC which is not suitable for personal computing.

I'm guessing Fujitsu did it to make it easier to port code from x86.

Denver/Carmel are supposedly VLIW cores which support AArch64 via JIT-emulation and maybe had the same idea that they could use TSO to efficiently emulate x86, as well.

It is called FEAT_AFP documented in ARMv8.7.

Cool. Then we should get good x86 emulation from other vendors, too. Do you know if it's a standard part of ARMv9-A? I'm guess it came too late for that.

[rmfx]

Shouldn't these kind of arch conversions be handled by the kernel itself ?

[QwertyChouskie]

Shouldn't these kind of arch conversions be handled by the kernel itself ?

CPU emulation/binary translation is more similar to a decompiler/compiler than anything you would find in a kernel. (Technically, you could shove whatever you want into a kernel, but there's 0 reason to for this type of thing.)

[gnattu]

Cool. Then we should get good x86 emulation from other vendors, too. Do you know if it's a standard part of ARMv9-A? I'm guess it came too late for that.

Arm's doc states that an Armv9.2 compliant implementation must also be Armv8.7 and Armv9.1 compliant, and this feature is mandatory in Armv8.7 implementations that implement floating-point support. So an Armv9.2 compliant processor that supporting floating-point has to have FEAT_AFP. For Armv9.0 processors that already available, yes the extension comes too late.

[Anux]

Second, for personal computers, Apple just proved it's totally feasible.

True but someone at Apple made a decision and everyone had to follow. In Linux most software is easily recompiled for any architecture so there is no real need to emulate. Afterall there is nothing wrong with x86 and it's plenty available from emmbedded to HPC.

If Apple can, Linux world can too.

Can? sure. Will? maybe.

[gnattu]

True but someone at Apple made a decision and everyone had to follow. In Linux most software is easily recompiled for any architecture so there is no real need to emulate. Afterall there is nothing wrong with x86 and it's plenty available from emmbedded to HPC.


Can? sure. Will? maybe.

It depends. The "easily recompiled" actually results in years of eco-system development. The RISC-V situation was far from "easily recompiled" years ago due to whatever compatibility issue you may encounter. It is in great shape now but we can still not compile chromium on some RISC-V processors because nodejs keeps crashing. The emulation need also comes from running windows-based games because you almost never get the source from Windows Apps.

[Anux]

It depends. The "easily recompiled" actually results in years of eco-system development. The RISC-V situation was far from "easily recompiled" years ago due to whatever compatibility issue you may encounter.

Ofcourse it's not that easy but still easier than making a performant emulater. Or do you know any emulators for x86 on RiscV?

The emulation need also comes from running windows-based games because you almost never get the source from Windows Apps.

You can always use x86 and wine, that's what I meant with "need". Whereas if your in the Apple cage you actually need an emulator or you are stuck with old badly designed hardware.

[coder]

Afterall there is nothing wrong with x86 and it's plenty available from emmbedded to HPC.

Oh sure. x86 is so devoid of deficiencies that Intel won't ever have to make any fundamental revisions to the core ISA:

https://www.phoronix.com/news/Intel-APX

/s

[Anux]

Oh sure. x86 is so devoid of deficiencies that Intel won't ever have to make any fundamental revisions to the core ISA:

Not sure what Intels extension segmentation has to do with that? You can allways buy AMD.

[ayumu]

Box86/64 supports a RISC-V host.

Whereas FEX Emu only supports the legacy ARM platform as host. Bummer.