From 0584216921b243fac91395aa8975dbc34997381a Mon Sep 17 00:00:00 2001
From: David Gibson <dgibson@redhat.com>
Date: Mon, 4 Dec 2017 06:30:08 +0100
Subject: [PATCH 28/36] Match POWER max cpus to x86

RH-Author: David Gibson <dgibson@redhat.com>
Message-id: <20171204063008.31826-1-dgibson@redhat.com>
Patchwork-id: 78091
O-Subject: [RHEL-7.5 qemu-kvm-rhev PATCH] [RHEL only] Match POWER max cpus to x86
Bugzilla: 1495456
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Serhii Popovych <spopovyc@redhat.com>

On at least some x86 configurations we now support 384 guest vcpus.
POWER supports more than that in theory, but set the cap to 384 as a
supported maximum for feature parity.  This includes updating the
downstream lie about what KVM supports (in fact it supports 2048 vcpus
as of right now).

As of the current kernel, even with this patch 384 vcpus can only be
created with threads=2 or greater (in the guest), otherwise the
spacing of guest vcpu numbers causes us to exhaust the 2048 vcpu ids
in KVM.  There are a few ways we could address that, which we'll track
as a different bug.

Testing: Started guest with -smp 384,threads=2 using new qemu

Signed-off-by: David Gibson <dgibson@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 accel/kvm/kvm-all.c | 4 ++--
 hw/ppc/spapr.c      | 3 ++-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 80ab1c7..94c4968 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1638,9 +1638,9 @@ static int kvm_init(MachineState *ms)
      *
      * However the POWER hard limit advertised by the kernel is 2048
      * (== NR_CPUS) but we only want to allow up to the number of
-     * vCPUs we actually test, so we force the hard limit to 240
+     * vCPUs we actually test, so we force the hard limit to 384
      */
-    hard_vcpus_limit = 240;
+    hard_vcpus_limit = 384;
     if (soft_vcpus_limit > hard_vcpus_limit) {
         soft_vcpus_limit = hard_vcpus_limit;
     }
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 6c64c55..8623996 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -3580,7 +3580,8 @@ static void spapr_machine_class_init(ObjectClass *oc, void *data)
     mc->init = ppc_spapr_init;
     mc->reset = ppc_spapr_reset;
     mc->block_default_type = IF_SCSI;
-    mc->max_cpus = 1024;
+    /* RHEL: set to max # of supported vcpus */
+    mc->max_cpus = 384;
     mc->no_parallel = 1;
     mc->default_boot_order = "";
     mc->default_ram_size = 512 * M_BYTE;
-- 
1.8.3.1