[HN Gopher] Felix86: Run x86-64 programs on RISC-V Linux
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       Felix86: Run x86-64 programs on RISC-V Linux
        
       Author : rguiscard
       Score  : 118 points
       Date   : 2025-05-02 00:07 UTC (22 hours ago)
        
 (HTM) web link (felix86.com)
 (TXT) w3m dump (felix86.com)
        
       | badmonster wrote:
       | What remaining challenges are you most interested in solving for
       | felix86--GPU driver support, full 32-bit compatibility, better
       | Wine integration, or something else entirely?
        
         | westurner wrote:
         | The felix86 compatibility list also lists SuperTux and
         | SuperTuxCart.
         | 
         | "lsteamclient: Add support for ARM64."
         | https://github.com/ValveSoftware/Proton/commit/8ff40aad6ef00...
         | .. https://news.ycombinator.com/item?id=43847860
         | 
         | /? box86:
         | https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...
         | 
         | "New box86 v0.3.2 and Box64 v0.2.4 released - RISC-V and WoW64
         | support" (2023) https://news.ycombinator.com/item?id=37197074
         | 
         | /? box64 is:pr RISC-V is:closed:
         | https://github.com/ptitSeb/box64/pulls?q=is%3Apr+risc-v+is%3...
        
       | JonChesterfield wrote:
       | Haven't found the source code
       | (https://github.com/orgs/felix86-emu/repositories looked likely
       | but no), curious whether this is a qemu fork or a DIY effort.
        
         | drmpeg wrote:
         | https://github.com/OFFTKP/felix86/
        
           | JonChesterfield wrote:
           | Nice, thanks! I appreciate seeing a bunch of the instruction
           | definitions written in a serialisation format (e.g. https://g
           | ithub.com/OFFTKP/felix86/blob/master/counts/SSE2.js...) as
           | opposed to C macros.
        
             | bonzini wrote:
             | Those are tests, it seems. The actual sources are at
             | https://github.com/OFFTKP/felix86/tree/master/src/felix86
             | and the disassembler is https://zydis.re.
        
       | guerrilla wrote:
       | This is good. Maybe it means some day we'll able to run Steam on
       | it. Wouldn't that be funny? Windows emulation on x86-64 emulation
       | on RISC-V.
        
         | snvzz wrote:
         | I am hopeful valve will release a risc-v build themselves.
         | 
         | And wine/proton will integrate with this or some similar
         | solution for running x86 binaries.
        
           | guerrilla wrote:
           | They can't. The games themselves are compiled for x86-64 and
           | closed source. It's not enough if they just recompiled Steam,
           | Proton, etc.
        
             | rwmj wrote:
             | It seems as if there are unofficial(?) Steam ports to Arm
             | which presumably run the x86-64 binaries in emulation, so
             | that would be a similar sort of thing.
        
       | OptionX wrote:
       | Always wondered why RISC-V doesn't get more mainstream adoption.
       | 
       | Even if not at the consumer level, having your data center, for
       | example, running a cheaper (I assume since no license for the
       | instruction set means not having to pay for it and more options
       | to buy from leading to lower prices) and less power demanding
       | option when compared to x86-64 sounds enticing to me.
       | 
       | Maybe no one wants to be the genea pig to iron out the kinks of
       | the transition or maybe the raw performance of x86 is bigger deal
       | than I think it is and its worth the price and power. Dunno.
        
         | bobmcnamara wrote:
         | > Always wondered why RISC-V doesn't get more mainstream
         | adoption.
         | 
         | For me, it's because the ecosystem has fragged even harder than
         | Xtensa, who will sell you custom CPUs. THead made yet another
         | vector unit that's required to approach anything near the
         | Intel/AMD moat numbers.
         | 
         | SpecInt/GHz last year was around half of Intel/AMD/ARM numbers.
         | 
         | The imminent demise of CISC has been trumpeted from the
         | rooftops for at least the last 30 years...
        
           | deaddodo wrote:
           | ARM isn't CISC and has, by sheer numbers, completely
           | dominated x86 for decades now; not counting the massive
           | number of MIPS, AVR, etc embedded chips.
           | 
           | Additionally, if you want to get super technical (as if there
           | were ever a real delineation between RISC/CISC), both AMD and
           | Intel decode x86 into internal micro-ops which are
           | essentially RISC.
           | 
           | So, for all intents and purposes, CISC _is_ dead _and_
           | buried.
        
             | jcranmer wrote:
             | > Additionally, if you want to get super technical (as if
             | there were ever a real delineation between RISC/CISC), both
             | AMD and Intel decode x86 into internal micro-ops which are
             | essentially RISC.
             | 
             | Given that most CISC chips also relied on microcoding and
             | micro-ops, x86 having micro-ops wouldn't have made it
             | anything like RISC as far as the original CISC/RISC debate
             | goes.
             | 
             | The only reason that the "x86 is really RISC because of
             | micro-ops" comes up is because x86 implementations are
             | superscalar, which was supposed to be impossible with RISC
             | chips, so people started coming up with the micro-op fudge
             | to salvage the story that you need RISC to be an advanced
             | modern microprocessor.
             | 
             | The truth is that CISC was never a meaningful category in
             | the first place (it was only ever "not-RISC"), and RISC
             | itself ceased to be a meaningful category around 30 years
             | ago.
        
         | Kampfschnitzel wrote:
         | From what I've seen, most RISC V chips are still far behind x86
         | and ARM when it comes to raw power. I don't think the loss in
         | performance is justifiable with lower cost (yet)
        
         | choffee wrote:
         | I think there has been a big uptake in things you don't see
         | like embedded or FPGA cores but as a general CPU it's nowhere
         | near as efficient as ARM/x86 right now is my understanding. So
         | it might be running in the SSD and the Fan controller but not
         | as the CPU. I think a large part of the cost of a CPU core is
         | not the instruction set but the optimisation of the CPU and
         | ARM/Intel/AMD are still way ahead in those. And so it needs
         | people to optimise the cores, which when they have done that
         | they charge for being a better CPU.
        
         | rwmj wrote:
         | There's a fair bit of adoption where you don't see it (for
         | example, if you have an NVidia GPU or a WD hard drive, you
         | likely have a few embedded RISC-V cores already). We're
         | expecting server hardware with good performance in a year or
         | two.
        
         | brucehoult wrote:
         | > Always wondered why RISC-V doesn't get more mainstream
         | adoption.
         | 
         | It's very simple!
         | 
         | Because the amount of time it takes to design and produce a
         | data centre level CPU microarchitecture is greater than the
         | time RISC-V extensions needed for data centre CPUs have
         | existed.
         | 
         | The original RISC-V specification was ratified less than six
         | years ago, but you really couldn't create a data centre CPU
         | until at least RVA22, ratified two years ago in March 2023 --
         | or preferably RVA23 which was ratified in October 2024 and has
         | the features needed for efficient hypervisors.
         | 
         | You can knock out a microcontroller CPU core in a weekend, but
         | something to compete with current Apple, AMD, Amazon etc CPUs
         | takes a long time to make. Most companies doing that started
         | work only in 2021 or 2022.
         | 
         | It is simply too soon. A lot of stuff is in the pipeline.
        
           | OptionX wrote:
           | Makes sense. There's always value in a maturity of a system
           | especially in the enterprise world.
        
         | junon wrote:
         | They're significantly slower than x86 and ARM at the moment.
        
         | usrusr wrote:
         | What fraction of the total cost of operating a datacenter do
         | you suppose goes into ARM licensing? That's how much more
         | efficient than RISC-V an ARM would have to be in order to make
         | it the preferred CPU in a "we don't need x86" scenario. That's
         | a very low bar to clear (for ARM, not for RISC-V)
        
         | Veserv wrote:
         | Any price advantage, even if we assumed a fully mature
         | ecosystem with equivalent processors and systems available, is
         | massively overstated. ARM had a total revenue of just ~3.7 G$
         | in 2024 over ~29 billion chips [1].
         | 
         | In contrast, Qualcomm, just one of many large suppliers of ARM-
         | based systems, had a total revenue of ~39 G$ and a operating
         | income of ~10 G$. ARM's _entire_ revenue would easily fit into
         | Qualcomm 's profit and only increase costs by ~12%. And that is
         | just one supplier. You have Samsung, Apple, Broadcom, Google,
         | Amazon, Nvidia, TI, NXP, etc. to help round that out.
         | 
         | The total impact of ARM licensing and IP costs is almost
         | certainly less than 1%. And given that RISC-V does not
         | currently have a fully mature ecosystem, you get to trade that
         | for a 1% cost improvement; not really a winning strategy right
         | now.
         | 
         | It is likely the main advantage in the long run for RISC-V is
         | that not requiring a license might enable a more vibrant
         | ecosystem due to removing the licensing barrier which might
         | enable better designs at comparable costs (because, again, the
         | cost differential should only be on the order of 1% in the long
         | run) rather than just creating comparable designs that just
         | chip off the licensing cost. That or RISC-V could win because
         | the giant manufacturers feel like putting the squeeze on ARM to
         | drive 1% off their BoM.
         | 
         | [1] https://www.acquired.fm/episodes/how-arm-became-the-
         | worlds-d...
        
           | gary_0 wrote:
           | Using 2024 numbers for ARM might not give a clear picture,
           | because that was many years after major companies like nVidia
           | and WD already switched all their major internal chips to
           | RISC-V. ARM's lunch was already partly eaten; many billions
           | of RISC-V chips were already in the wild in 2024. And
           | companies like Tenstorrent have been building high-
           | performance stuff on RISC-V for a while. If Jim Keller thinks
           | RISC-V is worth it, the advantage must be worth more than 1%.
        
             | Veserv wrote:
             | That speculation is trivially incorrect. ARM had a revenue
             | of 3.2 G$ in 2023, 2.7 G$ in 2022, 2 G$ in 2021.
        
       | ValdikSS wrote:
       | How's it different from box86/box64? It also has RISC-V with JIT
       | support.
       | 
       | https://box86.org/
        
       | sylware wrote:
       | Funny, I am doing exactly the other way around: I run small RV64
       | linux programs on x86_64 linux.
       | 
       | I cannot way for the first AAA games to run on ultra-performant
       | RISC-V(RV23+) microarchitectures made with the state-of-the-art
       | silicon process.
        
       | gitroom wrote:
       | Love that folks are hacking stuff like this already, even if
       | RISC-V still feels ages behind x86 for anything heavy. I def
       | wanna see how far these emulators can actually push things. Kinda
       | makes me hope for that wacky Steam-on-RISC-V future lol.
        
         | _joel wrote:
         | Almost heh
         | https://www.reddit.com/r/RISCV/comments/1jfkng6/windows_stea...
        
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       (page generated 2025-05-02 23:02 UTC)