Date: Tue, 13 Oct 2009 00:20:58 +0200 From: Juergen Lock <nox@jelal.kn-bremen.de> To: Blue Swirl <blauwirbel@gmail.com> Cc: freebsd-emulation@freebsd.org, Toni <tonygio04@gmail.com>, Juergen Lock <nox@jelal.kn-bremen.de>, Aleksej Saushev <asau@inbox.ru>, qemu-devel@nongnu.org Subject: Re: [Qemu-devel] Re: playing with qemu usermode emulation on FreeBSD... Message-ID: <20091012222058.GA43121@triton8.kn-bremen.de> In-Reply-To: <f43fc5580910121255i626e8c53t3ada32be0aa25a8f@mail.gmail.com> References: <20091007220549.GA65997@triton8.kn-bremen.de> <20091011221840.GA55502@triton8.kn-bremen.de> <f43fc5580910121255i626e8c53t3ada32be0aa25a8f@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Oct 12, 2009 at 10:55:24PM +0300, Blue Swirl wrote: > On Mon, Oct 12, 2009 at 1:18 AM, Juergen Lock <nox@jelal.kn-bremen.de> wrote: > > On Thu, Oct 08, 2009 at 12:05:49AM +0200, Juergen Lock wrote: > >> I recently noticed there are x86 bsd-user targets now (yeah I totally > >> missed those commits...) and now got it working a tiny little bit: > >> I can run > >> qemu-x86_64 -bsd freebsd /rescue/echo foo bar > >> here on FreeBSD 8/amd64 and it echoes foo bar as expected, but > >> segfaults afterwards. :) (in pthread_setcancelstate() invoked from > >> a guest write() syscall, in case anyone is wondering.) Other things > >> I tried either exit with errors or segfault as well, and i386 hosts > >> probably still don't work at all yet. (qemu-i386 here on amd64 does > >> at least something, but probably needs lock_user() treatment for all > >> kinds of syscalls, I only tried adding that for sysctl so far.) > >> > >> Anyway, here is an emulators/qemu-devel git head snapshot port > >> update with my current patches (files/patch-bsd-user), feel free to > >> test/debug/improve: > >> http://people.freebsd.org/~nox/qemu/qemu-devel-20091007.patch > >> (For the folks reading this on the qemu list: I shall start doing > >> `proper' patch submissions later, this is more for the FreeBSD folks > >> and because I was asked to send what I have...) > > > > New version at the same place, which now runs FreeBSD/{i386,sparc64} > > /rescue/echo on FreeBSD/amd64, the FreeBSD/amd64 target now segfaults > > in pthread_setcancelstate() invoked from the final writev() tho. > > Oh and I also uploaded the snapshot tarball so others can now actually > > build the port too... :) And I have switched to the cpu-exec.c patch > > posted by Aleksej Saushev on the qemu list and added back amd64 > > code there. > > > > Here is the bsd-user patch again: > > Please add Signed-off-by: line and use 'diff -u' (or preferably git diff). > Well I wasn't expecting this diff to be committed just yet anyway, it's still more a wip version... > > + if (1 /* bsd_type == target_freebsd */) > > + regs->rdi = infop->start_stack; > > Why the if and comment? > > > + if (1 /* bsd_type == target_freebsd */) { > > + regs->u_regs[8] = infop->start_stack; > > + regs->u_regs[11] = infop->start_stack; > > Same here. > Because bsd_type isn't available at these places in the code but probably should be checked, I still wanted to fix that. (Maybe make it global?) > > case 0x100: > > + /* FreeBSD uses 0x141 for syscalls too */ > > + case 0x141: > > + if (bsd_type != target_freebsd) > > + goto badtrap; > > You are now also trapping on case 0x100 if bsd_type != target_freebsd, > which probably breaks other BSDs. > Right, thats broken, the 0x141 case should come before the 0x100 here of course. > > +/* XXX this needs to be emulated on non-FreeBSD hosts... */ > > +static abi_long do_freebsd_sysctl(abi_ulong namep, int32_t namelen, abi_ulong oldp, > > + abi_ulong oldlenp, abi_ulong newp, abi_ulong newlen) > > What kind of call is this, is it possible to emulate on other BSDs? Is > it important? Its used mostly for things that on linux is done by manipulating /proc or /sys, like getting the kernel version, number of cpus, pagesize, etc. - and there are also sysctls that can be written to, like to enable ip forwarding or change sysV ipc settings. Although changes are usually restriced to root so `regular' executables rarely do them and I'm not really handling those yet. See here: http://www.freebsd.org/cgi/man.cgi?query=sysctl&apropos=0&sektion=3&manpath=FreeBSD+7.2-RELEASE&format=html > I'm just wondering if the cross-BSD emulation makes > sense after all. It would make the emulator much simpler if we could > assume that host_bsdness == target_bsdness. Yeah I was wondering about that too... Cheers, Juergen
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20091012222058.GA43121>