Re: [Qemu-trivial] [Qemu-devel] [RFC PATCH 4/4] qemu-options: Do not show -enable-kvm and -enable-hax in the docs anymore

[Eduardo Habkost <ehabkost@redhat.com>]

On Tue, Jun 26, 2018 at 03:05:33PM +0200, Paolo Bonzini wrote:
> On 26/06/2018 14:29, Eduardo Habkost wrote:
> > On Tue, Jun 26, 2018 at 07:57:18AM +0200, Paolo Bonzini wrote:
> >> On 25/06/2018 21:51, Eduardo Habkost wrote:
> >>> In either case, I'm not arguing (yet) for changing the default
> >>> upstream.  I'm just arguing for upstream QEMU to not make any
> >>> promises about the default.
> >>
> >> It would be a guest ABI breakage for TCG guests, so it would only apply
> >> to new machine types.  I don't think it's worth the complication.
> > 
> > That's exactly the point: I want to stop promising a stable guest
> > ABI when the accelerator is omitted, because I see no benefit in
> > wasting energy on this.
> 
> On the other hand I see no benefit in changing a default that people are
> obviously not using (since most people use KVM, not TCG).  Distros will
> keep shipping, and people will keep using qemu-kvm even if we change the
> default.

Not changing the default is different from promising we will keep
ABI compatibility if the accelerator is omitted.  I just want to
get rid of the latter.


> > (I don't think we ever kept the guest ABI correctly with TCG, by
> > the way.)
> 
> It would not be any different from KVM.  Less tested and likely to be
> more buggy, yes, but not particularly harder.

We can keep trying to not break it when "-accel tcg" is
explicitly provided.

-- 
Eduardo