On Mon, Nov 20, 2017 at 01:07:42PM +0100, Greg Kurz wrote:
> On Fri, 17 Nov 2017 15:50:53 +1100
> David Gibson <da...@gibson.dropbear.id.au> wrote:
>
> > On Tue, Nov 14, 2017 at 10:42:24AM +0100, Greg Kurz wrote:
> > > On Fri, 10 Nov 2017 15:20:11 +0000
> > > Cédric Le Goater <c...@kaod.org> wrote:
> > >
> > > > Let's define a new set of XICSFabric IRQ operations for the latest
> > > > pseries machine. These simply use a a bitmap 'irq_map' as a IRQ number
> > > > allocator.
> > > >
> > > > The previous pseries machines keep the old set of IRQ operations using
> > > > the ICSIRQState array.
> > > >
> > > > Signed-off-by: Cédric Le Goater <c...@kaod.org>
> > > > ---
> > > >
> > > > Changes since v2 :
> > > >
> > > > - introduced a second set of XICSFabric IRQ operations for older
> > > > pseries machines
> > > >
> > > > hw/ppc/spapr.c | 76
> > > > ++++++++++++++++++++++++++++++++++++++++++++++----
> > > > include/hw/ppc/spapr.h | 3 ++
> > > > 2 files changed, 74 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> > > > index 4bdceb45a14f..4ef0b73559ca 100644
> > > > --- a/hw/ppc/spapr.c
> > > > +++ b/hw/ppc/spapr.c
> > > > @@ -1681,6 +1681,22 @@ static const VMStateDescription
> > > > vmstate_spapr_patb_entry = {
> > > > },
> > > > };
> > > >
> > > > +static bool spapr_irq_map_needed(void *opaque)
> > > > +{
> > > > + return true;
> > >
> > > I see that the next patch adds some code to avoid sending the
> > > bitmap if it doesn't contain state, but I guess you should also
> > > explicitly have this function to return false for older machine
> > > types (see remark below).
> >
> > I don't see that you should need to migrate this at all. The machine
> > needs to reliably allocate the same interrupts each time, and that
> > means source and dest should have the same allocations without
> > migrating data.
> >
>
> Is this true for MSIs ? With the current code, the guest can change
> the allocation of such interrupts with the ibm,rtas-change-msi RTAS
> call. How can the dest know about that ?
Yeah, true. The MSIs really are dynamically allocated by the guest
and so will need to have information migrated.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
