From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0859FC636D6 for ; Fri, 17 Feb 2023 16:05:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pT3EA-00044n-3Z; Fri, 17 Feb 2023 11:04:50 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pT3E8-00043f-63 for qemu-devel@nongnu.org; Fri, 17 Feb 2023 11:04:48 -0500 Received: from mail-ed1-x52e.google.com ([2a00:1450:4864:20::52e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1pT3E4-0000uM-TK for qemu-devel@nongnu.org; Fri, 17 Feb 2023 11:04:47 -0500 Received: by mail-ed1-x52e.google.com with SMTP id g29so1149216eda.5 for ; Fri, 17 Feb 2023 08:04:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bsdimp-com.20210112.gappssmtp.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=DOlw6I1Krs04agT4rdADeZfSSB5JoAhXaqfCeO8n06I=; b=GCOtGr3Tnuqpbp7oF3cH1cJFg0C30a+9e2M9wgKp4cKFfDmjit7WDwsD16iygJr05F HuxtX/4RyPvXk3lWXcsDv+KtWC5h7z1Xb4Pqo2AbkQZ5QC6+3fhWAYOLB7sDthgSPY9Y kqANFIQ+qeupYgTMQiScUWpAwgkQwyNidZ/2YBdKuCe2xZw1lw3zpB/93Kbulj+1WM0i HXsS6nzC16oi9WRaIoLg5rb+D4HPkL0gdsuLtO/a4/iiPma5+TSxM0+qLw4pJpJx4kRy cDDfLHDD0Dew3H7z7i6V8CODTeIvusW2xqB6MtRW5LIVv+Dz7Akl+chwfanVX5w/GfXc IB1Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=DOlw6I1Krs04agT4rdADeZfSSB5JoAhXaqfCeO8n06I=; b=tdXD1GPPSdYAuhln1BeujeFqIPVfGJ6UCd/jCfmvD4OuJ9KJfqKIpO8sfIR0ZqsPCp Oce6mIMXv2FlFNqZvLM0xBzvZ2TP1Xb4hV7FpZw3qPgFKK/Yoj7ldks9yAdP9qRAv/bD xIO1ncRIDZrMB0KT+XXJ+/2Yu9o01Tr5Qv6IJWpI68Ajb+f4Pwob3deehk2f9osn5jjv SvggDdWNaJcIzXGVfgFwMshyAi5v9SdumbyBWsuHhbbW+I2cVfRS9zSt83m0jcz1HM7q QJrBkHUeQ0ajkEN8vUVzVpqCl0YHgDd/HYw16cORgkKPsSn/4VIirJ3EHeGUP7y4HD9D QhAA== X-Gm-Message-State: AO0yUKVyXb/ANJsn8mMdB7Nv1lSLl6du3VnKyjTJKEU3TiLevOXQBd8N Bl/0GslO4IJYR3iXS7lNZ4JZtMHXQCxCHgfpMBuZOw== X-Google-Smtp-Source: AK7set8Mac+S+ab4lAbPXGwiJvZMIcPezLIS29Xk+kfI/jcN+otFgJ/1WrpSG3w01E350SoX6aDKwV1LTiJvaaqToXU= X-Received: by 2002:a50:bb43:0:b0:4ac:b74b:a6a3 with SMTP id y61-20020a50bb43000000b004acb74ba6a3mr976772ede.0.1676649881877; Fri, 17 Feb 2023 08:04:41 -0800 (PST) MIME-Version: 1.0 References: <4ea862746a066107573650d04f4eee6992e0ede9.camel@infradead.org> <5c7026171d3ab5d530784308a5ce71d32e6760c7.camel@infradead.org> In-Reply-To: <5c7026171d3ab5d530784308a5ce71d32e6760c7.camel@infradead.org> From: Warner Losh Date: Fri, 17 Feb 2023 09:04:48 -0700 Message-ID: Subject: Re: Runnig solaris binary(32 bit) on linux(64 bit) To: David Woodhouse Cc: Richard Henderson , Peter Maydell , ginu samuel , qemu-devel@nongnu.org Content-Type: multipart/alternative; boundary="0000000000009f515705f4e778c1" Received-SPF: none client-ip=2a00:1450:4864:20::52e; envelope-from=wlosh@bsdimp.com; helo=mail-ed1-x52e.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --0000000000009f515705f4e778c1 Content-Type: text/plain; charset="UTF-8" On Thu, Feb 16, 2023 at 12:40 PM David Woodhouse wrote: > On Thu, 2023-02-16 at 09:29 -1000, Richard Henderson wrote: > > On 2/16/23 09:02, David Woodhouse wrote: > > > It wouldn't be beyond the wit of man to extend qemu-user to support the > > > similar personality variations for SCO/Solaris/etc. using that as a > > > guide. > > > > Not beyond wit but perhaps beyond patience. > > > > It would certainly be possible to emulate the "easy middle" of one POSIX > guest on a > > different POSIX host. But the dusty corners are going to get in the > way, where we > > currently rely on guest and host having identical semantics, and pass > the system call > > through to the host. > > > > It's a big job. > > True, but the existing iBCS / linux-abi kernel patches should highlight > a lot of those dusty corners. > So one thing to understand, the iBCS is a separate ABI. This means that you'd have to rewrite everything from the syscall dispatch on down. Even if this were relevant, it would be a huge job. A lot would depend on how much of Solaris is used. Solaris is ELF, which is good (it would be even worse if it were SunOS 4, then it's a.out and a whole lot of other complication that's more of a bsd-user thing). However, as others have pointed out, linux-user assumes a linux kernel. While one can run linux-user on FreeBSD with its Linux ABI implementation, even that's quite limited in what it can do (I needed to do this for some kexec support I was adding to FreeBSD boot loader that ran as a Linux binary). I had to make tweaks to FreeBSD's emulation to make it work, and that was for a binary that used only 10 system calls, no threads, no signals, nothing "messy" and apart from some extensions to 64-bits, nothing that wasn't in 7th Edition Unix. And there's also a number of special filesystems, IIRC, on Solaris that are used like linux's /sys and /proc filesystems, but with different details. And a million other details. Knowing the details isn't enough, assuming you could know them from cribbing from existing code. You have to actually go implement the details and that would be a very tedious job. Even if you kept it to a subset that your program uses... I started on a Venix emulator (ancient Unix V7 port to 8088/8086 micros I cut my teeth on), and even that was daunting. Now, with 3 years of bsd-user hacking and upstreaming under my belt, it would be easier, but there's a *HUGE* learning curve to understand the CPU, its exception model, how system calls are handled, how memory is mapped, etc. And the 'assume we're on linux' is definitely leveraged for memory mapping in the existing linux-user code if you were to copy it all as a starting point. When people say it's a big job, they are underselling it somewhat. It would be a big job for the maintainers of linux-user who have all the context and know where the gotchas are. For anybody else, learning everything you need to know itself is a big job. Your best bet is qemu-sparc-system + Solaris install. Warner P.S. Sorry to go into partial rant mode, but 4 years ago when I started helping the folks working with bsd-user, I thought how hard could it be... now I know... --0000000000009f515705f4e778c1 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


=
On Thu, Feb 16, 2023 at 12:40 PM Davi= d Woodhouse <dwmw2@infradead.org<= /a>> wrote:
O= n Thu, 2023-02-16 at 09:29 -1000, Richard Henderson wrote:
> On 2/16/23 09:02, David Woodhouse wrote:
> > It wouldn't be beyond the wit of man to extend qemu-user to s= upport the
> > similar personality variations for SCO/Solaris/etc. using that as= a
> > guide.
>
> Not beyond wit but perhaps beyond patience.
>
> It would certainly be possible to emulate the "easy middle" = of one POSIX guest on a
> different POSIX host.=C2=A0 But the dusty corners are going to get in = the way, where we
> currently rely on guest and host having identical semantics, and pass = the system call
> through to the host.
>
> It's a big job.

True, but the existing iBCS / linux-abi kernel patches should highlight
a lot of those dusty corners.

(it would be even worse if it w= ere SunOS 4, then it's a.out and a whole lot of other
complication that's more of a bsd-user thing). However= , as others have pointed
out, linux-user as= sumes a linux kernel. While one can run linux-user on FreeBSD
needed to do = this for some kexec support I was adding to FreeBSD boot loader
to make it work, and= that was for a binary that used only 10 system calls, no
threads, no signals, nothing "messy" and apart f= rom some extensions to 64-bits,
nothing tha= t wasn't in 7th Edition Unix.

<= /div>
And there's also a number of special fi= lesystems, IIRC, on Solaris that are used
l= ike linux's /sys and /proc filesystems, but with different details. And= a million other
details. Knowing the detai= ls isn't enough, assuming you could know them from
cribbing from existing code. You have to actually go implement = the details and
that would be a very tediou= s job. Even if you kept it to a subset that your program
uses...

I started on a Venix emulator (ancient Unix V7 port to = 8088/8086 micros I cut my
teeth on), and ev= en that was daunting. Now, with 3 years of bsd-user hacking and
upstreaming under my belt, it would be easier, but the= re's a *HUGE* learning curve
to underst= and the CPU, its exception model, how system calls are handled, how
memory is mapped, etc. And the 'assume we'= re on linux' is definitely leveraged
fo= r memory mapping in the existing linux-user code if you were to copy it all=
as a starting point.

When people say it's a = big job, they are underselling it somewhat. It would be
where the gotchas are.= For anybody else, learning everything you need to
know itself is a big job.

<= /div>
Your best bet is qemu-sparc-system + Solari= s install.

Warner

P.S. Sorry to go into partial rant mode, but 4 years ago when I s= tarted helping
the folks working with bsd-u= ser, I thought how hard could it be... now I know...
--0000000000009f515705f4e778c1--