From 4da5757f8ad715c203e2ef9320c49432e8259ee8 Mon Sep 17 00:00:00 2001

From: David Gibson <dgibson@redhat.com>

Date: Thu, 30 May 2019 04:37:23 +0100

Subject: [PATCH 2/8] spapr: Fix ibm, max-associativity-domains property number

 of nodes

RH-Author: David Gibson <dgibson@redhat.com>

Message-id: <20190530043728.32575-2-dgibson@redhat.com>

Patchwork-id: 88418

O-Subject: [RHEL-8.1 qemu-kvm PATCH 1/6] spapr: Fix ibm, max-associativity-domains property number of nodes

Bugzilla: 1710662

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Auger Eric <eric.auger@redhat.com>

RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

From: Serhii Popovych <spopovyc@redhat.com>

Laurent Vivier reported off by one with maximum number of NUMA nodes

provided by qemu-kvm being less by one than required according to

description of "ibm,max-associativity-domains" property in LoPAPR.

It appears that I incorrectly treated LoPAPR description of this

property assuming it provides last valid domain (NUMA node here)

instead of maximum number of domains.

  ### Before hot-add

  (qemu) info numa

  3 nodes

  node 0 cpus: 0

  node 0 size: 0 MB

  node 0 plugged: 0 MB

  node 1 cpus:

  node 1 size: 1024 MB

  node 1 plugged: 0 MB

  node 2 cpus:

  node 2 size: 0 MB

  node 2 plugged: 0 MB

  $ numactl -H

  available: 2 nodes (0-1)

  node 0 cpus: 0

  node 0 size: 0 MB

  node 0 free: 0 MB

  node 1 cpus:

  node 1 size: 999 MB

  node 1 free: 658 MB

  node distances:

  node   0   1

    0:  10  40

    1:  40  10

  ### Hot-add

  (qemu) object_add memory-backend-ram,id=mem0,size=1G

  (qemu) device_add pc-dimm,id=dimm1,memdev=mem0,node=2

  (qemu) [   87.704898] pseries-hotplug-mem: Attempting to hot-add 4 ...

  <there is no "Initmem setup node 2 [mem 0xHEX-0xHEX]">

  [   87.705128] lpar: Attempting to resize HPT to shift 21

  ... <HPT resize messages>

  ### After hot-add

  (qemu) info numa

  3 nodes

  node 0 cpus: 0

  node 0 size: 0 MB

  node 0 plugged: 0 MB

  node 1 cpus:

  node 1 size: 1024 MB

  node 1 plugged: 0 MB

  node 2 cpus:

  node 2 size: 1024 MB

  node 2 plugged: 1024 MB

  $ numactl -H

  available: 2 nodes (0-1)

  ^^^^^^^^^^^^^^^^^^^^^^^^

             Still only two nodes (and memory hot-added to node 0 below)

  node 0 cpus: 0

  node 0 size: 1024 MB

  node 0 free: 1021 MB

  node 1 cpus:

  node 1 size: 999 MB

  node 1 free: 658 MB

  node distances:

  node   0   1

    0:  10  40

    1:  40  10

After fix applied numactl(8) reports 3 nodes available and memory

plugged into node 2 as expected.

>From David Gibson:

------------------

  Qemu makes a distinction between "non NUMA" (nb_numa_nodes == 0) and

  "NUMA with one node" (nb_numa_nodes == 1).  But from a PAPR guests's

  point of view these are equivalent.  I don't want to present two

  different cases to the guest when we don't need to, so even though the

  guest can handle it, I'd prefer we put a '1' here for both the

  nb_numa_nodes == 0 and nb_numa_nodes == 1 case.

This consolidates everything discussed previously on mailing list.

Fixes: da9f80fbad21 ("spapr: Add ibm,max-associativity-domains property")

Reported-by: Laurent Vivier <lvivier@redhat.com>

Signed-off-by: Serhii Popovych <spopovyc@redhat.com>

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

Reviewed-by: Greg Kurz <groug@kaod.org>

Reviewed-by: Laurent Vivier <lvivier@redhat.com>

(cherry picked from commit 3908a24fcb83913079d315de0ca6d598e8616dbb)

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1710662

Signed-off-by: David Gibson <dgibson@redhat.com>

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>

---

 hw/ppc/spapr.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c

index ea72782..b57c0be 100644

--- a/hw/ppc/spapr.c

+++ b/hw/ppc/spapr.c

@@ -915,7 +915,7 @@ static void spapr_dt_rtas(sPAPRMachineState *spapr, void *fdt)

         cpu_to_be32(0),

         cpu_to_be32(0),

         cpu_to_be32(0),

-        cpu_to_be32(nb_numa_nodes ? nb_numa_nodes - 1 : 0),

+        cpu_to_be32(nb_numa_nodes ? nb_numa_nodes : 1),

     };

     _FDT(rtas = fdt_add_subnode(fdt, 0, "rtas"));

-- 

1.8.3.1