Re: [Qemu-devel] [PATCH 2/2] tcg/i386: Reserve register for guest_base if a segment isn't available

[Richard Henderson]

On 07/17/2015 02:33 AM, Peter Maydell wrote:
> On 16 July 2015 at 22:25, Richard Henderson <address@hidden> 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?

We've only bothered to fill in code for Linux so far.

These days we should probably probe for fsgsbase insns and use those.  Though I 
don't know how many of the various operating systems enable that...


r~