Re: [PATCH for-6.0] spapr: Allow memory unplug to always succeed

[Greg Kurz]

On Thu, 10 Dec 2020 14:38:44 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Tue, Dec 08, 2020 at 10:06:09AM +0100, Greg Kurz wrote:
> > On Tue, 8 Dec 2020 15:30:04 +1100
> > David Gibson <david@gibson.dropbear.id.au> wrote:
> > 
> > > On Mon, Dec 07, 2020 at 02:37:04PM +0100, Greg Kurz wrote:
> > > > It is currently impossible to hot-unplug a memory device between
> > > > machine reset and CAS.
> > > > 
> > > > (qemu) device_del dimm1
> > > > Error: Memory hot unplug not supported for this guest
> > > > 
> > > > This limitation was introduced in order to provide an explicit
> > > > error path for older guests that didn't support hot-plug event
> > > > sources (and thus memory hot-unplug).
> > > > 
> > > > The linux kernel has been supporting these since 4.11. All recent
> > > > enough guests are thus capable of handling the removal of a memory
> > > > device at all time, including during early boot.
> > > > 
> > > > Lift the limitation for the latest machine type. This means that
> > > > trying to unplug memory from a guest that doesn't support it will
> > > > likely just do nothing and the memory will only get removed at
> > > > next reboot. Such older guests can still get the existing behavior
> > > > by using an older machine type.
> > > > 
> > > > Signed-off-by: Greg Kurz <groug@kaod.org>
> > > 
> > > Looks like this conflicts with something I've added to for-6.0
> > > recently.  Can you rebase and resend, please.
> > > 
> > 
> > I'm not quite sure what for-6.0 you're talking about. Despite
> > you're recent announcement about moving to gitlab, it seems
> > that the branch at github is the most up to date.
> > 
> > gitlab:
> > - HEAD is "xive: Add trace events"
> > - Date: 26 Nov, 2020
> > 
> > github:
> > - HEAD is "MAINTAINERS: Add Greg Kurz as co-maintainer for ppc"
> > - Date: Dec 4, 2020
> > 
> > I've thus based this patch on github. Also, this is based on Connie's
> > "hw: add compat machines for 6.0" patch...
> > 
> > > > ---
> > > > Based-on: 20201109173928.1001764-1-cohuck@redhat.com
> > 
> > ... maybe I should have made it more clear than just
> > mentioning the message id ?
> > 
> > I think I'll just wait for Connie's patch to get merged and I'll repost 
> > after
> > you've rebased ppc-for-6.0.
> 
> Sorry, I think I forgot to push the latest to either gitlab *or*
> github.  I've pushed some new stuff now.
> 

Np. I see you now have the 6.0 compat machine types in your tree on gitlab.
This patch should apply flawlessly.

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