11:00 <linkmauve> Hi, I built an amd64 Mesa with just panfrost in order to run it in FEX-Emu on a rk3588, is that the proper way to do it or should I instead rely entirely on thunking to the host Mesa?

11:37 <alyssa> linkmauve: that's more of a FEX question than a Panfrost one but

11:38 <alyssa> in principle that should work

11:38 <alyssa> and "Linux FEX" (including when you use FEX to emulate an x86 wine binary), depends on having those host libraries, since we treat thunking as "just" an optimization

11:38 <alyssa> (notably, Steam breaks with thunking rn for some reason..)

11:39 <alyssa> thunking of course improves performance

11:39 <linkmauve> I won’t be using Steam anyway.

11:39 <alyssa> OK

11:39 <alyssa> "Windows FEX" (including when you use a FEX dll with an arm64 build of Wine), does not use host libraries, and is thunked 100% of the time (inside Wine, not FEX)

11:40 <alyssa> which means wine-arm64ec generally gets better performance than linux FEX + x86 wine -- since you're not emulating wine itself / the windows system library

11:40 <alyssa> also, Steam is broken with wine-arm64ec (-:

11:40 <linkmauve> Oh, I want to try this Windows FEX as well!

11:41 <alyssa> you may need a sufficiently new Mesa for the fix in https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34573

11:41 <linkmauve> So this one rely entirely on AArch64 userland, no need for any rootfs?

11:41 <alyssa> Correct

11:41 <alyssa> Or well, the "rootfs" is your wine prefix

11:41 <linkmauve> I’m running Mesa main always.

11:42 <alyssa> Windows FEX and Linux FEX are very similar, it's just that Linux FEX has to simulate a Linux environment (including rootfs), whereas Windows FEX gets to be "just" an emulator since WINE simulates a Windows environment (including the rootfs at ~/.wine/drive_c )

11:43 <alyssa> FWIW, on Asahi we ship Linux FEX + x86 steam since that's what actually works today

11:43 <alyssa> although I use custom builds of Windows FEX for testing locally

11:43 <linkmauve> Do you have any instructions to build Windows FEX?

11:43 <linkmauve> I already have Linux FEX built and running.

11:49 <linkmauve> Speaking of Linux FEX though, how do you install packages in your rootfs? Here FEXInterpreter complains that my rootfs isn’t mounted as suid (even though it is) when using sudo.

11:52 <alyssa> generally you don't

11:52 <linkmauve> How do you maintain your rootfs then, with updates and such? Through qemu?

11:53 <alyssa> generally you don't

11:53 <alyssa> it's like an immutable distro

11:53 <alyssa> we prebake one big rootfs for e.g. fedora 42

11:53 <alyssa> then it says the same until you upgrade the whole system to fedora 43 (incl a new rootfs)

11:54 <alyssa> https://github.com/FEX-Emu/FEX/pull/4632 https://wiki.fex-emu.com/index.php/Development:ARM64EC

11:54 <alyssa> no good guide but you should be able to cobble it together

11:54 <alyssa> the wiki's out of date

11:58 <linkmauve> Ah, I’m using an old amd64 laptop’s NVMe which was running ArchLinux, so ideally I would just keep it up to date and emulate it as normal.

11:58 <linkmauve> I’ll try to figure out how to do that, maybe using qemu instead of FEX.

12:08 <alyssa> Uhhh

12:08 <alyssa> Yeah that's not really how this is supposed to work lol