On 08/27/2015 03:14 PM, Mark Morgan Lloyd wrote: > The (unofficial?) FAQ at http://uml.devloop.org.uk/faq.html implies that > it is possible to build UML on a 64-bit system to run a 32-bit guest. > > The best that I can manage on e.g. Debian "Jessie" x86-64 is to use > make ARCH=um SUBARCH=i386 which results in a 32-bit ELF to presumably > run a 32-bit guest. Prerequisites appear to be the multiarch-support > and gcc-multiarch packages. > > Is it possible to build UML as a 64-bit binary, but to run a 32-bit > guest? What I'd like to be able to do is to put it on a system which has > no multiarch stuff, i.e. to completely sequester the 32-bit libraries > etc. within the guest filesystem. > > [Background: I used UML fairly heavily in the 2.4 era, but I'm a > comparative newcomer to x86-64. I'm trying to avoid overuse of > multi-arch stuff.] >
UML 32 bits works on 64 bits because the 32 bits ISA is available. I don't think it is possible on the other way (albeit pure emulation). J. ------------------------------------------------------------------------------ _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
