-Several factors influence the choice:
-
-(a) The host architecture.
-
-(b) The guest architecture.
-
-(c) What kernel(s) we find at runtime.
-
-(d) What compiler(s) we find at configure time.
-
-(e) In general, we would prefer to run a 32 bit kernel over a 64 bit
-kernel, because that reduces the amount of system memory we have to
-give to qemu significantly, and makes libguestfs smaller, faster and
-use less memory.
-
-For example, if (a) the host is x86-64, then it might be running a
-mixture of (b) i386 and x86-64 guests. Disk formats are stable, even
-across 32 and 64 bit and endianness changes, so it doesn't really
-matter what kernel we use if we just want to access files in the
-guest. In the absence of any other factors, we would choose an i386
-kernel and run it in plain 'qemu', because that would use the least
-amount of memory.
-
-But if we wanted to enable the feature of running a guest program in
-an x86-64 guest, then we have to run an x86-64 kernel and
-qemu-system-x86_64 (an i386 kernel can't run 64 bit programs). The
-same applies if we didn't find a 32 bit kernel at runtime, or if we
-couldn't run "gcc -m32" at configure time (because we can't compile
-the daemon).
-
-SO: to enable maximum features on 64 bit architectures:
-
-(1) Ensure that "gcc -m32" can create usable binaries.
-
-(2) Provide 32 and 64 bit kernels binaries at runtime.
-
-If you have a really weird environment, eg. you want to run programs
-inside PPC64 guests on your MIPS machine, then:
-
-(3) Provide gcc cross-compiler and glibc for each architecture, and
-cross-compile the daemon and NFS server:
-
- mkdir daemon/build-ppc64
- pushd daemon/build-ppc64
- ../configure --host=ppc64-gnu-linux
- make
- popd
git.annexia.org / libguestfs.git / commitdiff