Re: [Qemu-devel] [PATCH v5 0/2] e1000: add interrupt mitigation support

[Stefan Hajnoczi]

On Wed, Jul 31, 2013 at 03:39:05PM +0200, Vincenzo Maffione wrote:
> Ok, but it's unclear how do you prefer to create and "empty"
> PC_COMPAT_1_6 in Patch 1.
> If you want to keep this declaration form
> 
> [...]
> .compat_props = (GlobalProperty[]) {
>         PC_COMPAT_1_6,
>         { /* end of list */ }
>     },
> [...]
> 
> in the two pc_*_machine_v1_6 structs, I'm forced to define
> 
> #define PC_COMPAT_1_6 { /*empty*/ }
> 
> but then I can't extend PC_COMPAT_1_5 with PC_COMPAT_1_6 as "header"
> (like you guys do for PC_COMPAT_1_5 and PC_COMPAT_1_4), because
> otherwise PC_COMPAT_1_6 would act as a premature terminator for
> PC_COMPAT_1_5 (right?).
> 
> Should I extend PC_COMPAT_1_5 with PC_COMPAT_1_6 as a "tail", or
> should I avoid extending it in the Patch 1, and do the extension in
> Patch 2 (when I have a non-empty PC_COMPAT_1_6)?

You are right, (GlobalProperty[]) {, {...}} is not valid syntax.  In
that case I would switch PC_COMPAT_1_6 into the e1000 interrupt
mitigation patch.  That way the patches are bisectable.

You can still introduce the QEMU 1.7 pc machine type as a separate
patch if you wish, but I no longer see a big win if PC_COMPAT_1_6 cannot
be isolated from the e1000 change.

Andreas: Do you agree to do everything in a single patch?

Stefan