Re: [Qemu-devel] [PATCH 2/5] configure: Don't allow user-only targets for unknown CPU architectures

[Richard Henderson]

On 06/14/2016 02:52 AM, Peter Maydell wrote:
> For the user-only targets, we need to know something about the host CPU
> architecture even if we are using the TCI interpreter rather than TCG.
> (In particular user-exec.c has code for handling signals that needs
> to know about that host's context structures.)
> 
> Specifically forbid building the user-only targets on unknown CPU
> architectures, rather than allowing them to configure but then fail
> when building user-exec.c.
> 
> This change drops supports for two configurations which were theoretically
> possible before:
>  * linux-user targets on M68K hosts using TCI
>  * linux-user targets on HPPA hosts using TCI
> 
> We don't think anybody is actually trying to use these in practice, though:
>  * interpreted TCG on a slow host CPU would be unusably slow
>  * the m68k user-exec.c support is missing is_write detection so guest
>    code which writes to the same page it is executing from was broken
>    (will include any guest program using signals)
>  * HPPA TCG backend support was dropped two and a half years ago
>    with no complaints
> 
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>  configure | 7 +++++++
>  1 file changed, 7 insertions(+)


Reviewed-by: Richard Henderson <address@hidden>


r~