Dimitri John Ledkov <dimitri.led...@canonical.com> writes: > BugLink: https://bugs.launchpad.net/bugs/2038587 > > ppc64le is exclusively little endian and 64-bit, thus there is no need > for COMPAT_32BIT_TIME, nor COMPAT.
To be pedantic, the ppc64le kernel does support running 32-bit little endian userspace in compat mode (CONFIG_COMPAT=y). It's a distro choice as to whether you support COMPAT. Notably there are two other major distros that don't support COMPAT for ppc64le, and the set of 32-bit LE software is effectively empty. > diffconfig result of these changes is: > > -ARCH_MMAP_RND_COMPAT_BITS 13 > -ARCH_WANT_COMPAT_IPC_PARSE_VERSION y > -ARCH_WANT_OLD_COMPAT_IPC y > -COMPAT_BINFMT_ELF y > -COMPAT_NETLINK_MESSAGES y > -COMPAT_OLD_SIGACTION y > -HAVE_ARCH_MMAP_RND_COMPAT_BITS y > -KVM_COMPAT y > -NETFILTER_XTABLES_COMPAT y > -SYSVIPC_COMPAT y > -VDSO32 y > COMPAT y -> n > COMPAT_32BIT_TIME y -> n > +ARCH_HAS_SYSCALL_WRAPPER y > +INTERRUPT_SANITIZE_REGISTERS y > > What confused me, if the above combination is even valid or just pure > dead code. I don't entirely understand what that diff is saying, but I'll try and answer anyway. > Is it really possible to run 32bit big-endian KVM on a 64bit > little-endian POWER? Are you referring to KVM_COMPAT being disabled? That's nothing to do with big-endian. It's just controlling whether the KVM ioctls (which qemu calls) support compat handling, ie. whether you can run a 32-bit qemu under a 64-bit kernel. It's entirely expected that when COMPAT is turned off KVM_COMPAT also gets turned off. > Or is Kconfig slightly buggy and should be fixed up to prevent > offering COMPAT options when little-endian 64bit POWER kernel is being > configured? No. Like I said at the top, the kernel does support 32-bit LE compat, eventhough it's not very widely used. cheers
