On 2015-07-17 17:30, Paolo Bonzini wrote: > > > On 17/07/2015 03:33, Peter Maydell wrote: > > On 16 July 2015 at 22:25, Richard Henderson <r...@twiddle.net> wrote: > > > This saves 2 insns and 10 bytes from the implementation of > > > each memory operation. > > > > Do we have an idea of which platforms/configs don't let > > us have a segment register for guest_base? > > Everything non-Linux I think, which for user-mode emulation means bsd-user.
Linux might also not allow to use a segment register if the prctl call with ARCH_SET_GS fails. OTOH I have no idea why it can fail, but we actually check that it doesn't fail before using %gs. -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
