qemu-kvm/SOURCES/0015-globally-limit-the-maximum-number-of-CPUs.patch

From c9c3cf721b0e9e359418f64c2a5121c3f8b5d27a Mon Sep 17 00:00:00 2001
From: Andrew Jones <drjones@redhat.com>
Date: Tue, 21 Jan 2014 10:46:52 +0100
Subject: globally limit the maximum number of CPUs

We now globally limit the number of VCPUs.
Especially, there is no way one can specify more than
max_cpus VCPUs for a VM.

This allows us the restore the ppc max_cpus limitation to the upstream
default and minimize the ppc hack in kvm-all.c.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
Signed-off-by: Danilo Cesar Lemes de Paula <ddepaula@redhat.com>

Rebase notes (2.11.0):
- Removed CONFIG_RHV reference
- Update commit log

Merged patches (2.11.0):
- 92fef14623 redhat: remove manual max_cpus limitations for ppc
- bb722e9eff redhat: globally limit the maximum number of CPUs
- fdeef3c1c7 RHEL: Set vcpus hard limit to 240 for Power
- 0584216921 Match POWER max cpus to x86

Signed-off-by: Andrew Jones <drjones@redhat.com>
(cherry picked from commit a4ceb63bdc5cbac19f5f633ec761b9de0dedb55e)
(cherry picked from commit a1f26d85171b4d554225150053700e93ba6eba10)

redhat: globally limit the maximum number of CPUs

RH-Author: David Hildenbrand <david@redhat.com>
Message-id: <20180109103253.24517-2-david@redhat.com>
Patchwork-id: 78531
O-Subject: [RHEL-7.5 qemu-kvm-ma PATCH v2 1/2] redhat: globally limit the maximum number of CPUs
Bugzilla: 1527449
RH-Acked-by: David Gibson <dgibson@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

Upstream-status: n/a

For RHEL, we support 240, for RHV up to 384 VCPUs. Let's limit this
globally instead of fixing up all machines. This way, we can easily
change (increase) the product specific levels later.

Signed-off-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

redhat: remove manual max_cpus limitations for ppc

RH-Author: David Hildenbrand <david@redhat.com>
Message-id: <20180109103253.24517-3-david@redhat.com>
Patchwork-id: 78532
O-Subject: [RHEL-7.5 qemu-kvm-ma PATCH v2 2/2] redhat: remove manual max_cpus limitations for ppc
Bugzilla: 1527449
RH-Acked-by: David Gibson <dgibson@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Cornelia Huck <cohuck@redhat.com>

Upstream-status: n/a

RH-Author: Andrew Jones <drjones@redhat.com>
Message-id: <1390301212-15344-1-git-send-email-drjones@redhat.com>
Patchwork-id: 56862
O-Subject: [RHEL7.0 qemu-kvm PATCH v6] use recommended max vcpu count
Bugzilla: 998708
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>

The recommended vcpu max limit (KVM_CAP_NR_VCPUS) should be used instead
of the actual max vcpu limit (KVM_CAP_MAX_VCPUS) to give an error.

This commit matches the limit to current KVM_CAP_NR_VCPUS value.

Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 accel/kvm/kvm-all.c | 12 ++++++++++++
 vl.c                | 18 ++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index ca00daa2f5..dc3ed7f04e 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1943,6 +1943,18 @@ static int kvm_init(MachineState *ms)
     soft_vcpus_limit = kvm_recommended_vcpus(s);
     hard_vcpus_limit = kvm_max_vcpus(s);
 
+#ifdef HOST_PPC64
+    /*
+     * On POWER, the kernel advertises a soft limit based on the
+     * number of CPU threads on the host.  We want to allow exceeding
+     * this for testing purposes, so we don't want to set hard limit
+     * to soft limit as on x86.
+     */
+#else
+    /* RHEL doesn't support nr_vcpus > soft_vcpus_limit */
+    hard_vcpus_limit = soft_vcpus_limit;
+#endif
+
     while (nc->name) {
         if (nc->num > soft_vcpus_limit) {
             warn_report("Number of %s cpus requested (%d) exceeds "
diff --git a/vl.c b/vl.c
index 9f3e7e7733..1550aa2aaa 100644
--- a/vl.c
+++ b/vl.c
@@ -134,6 +134,8 @@ int main(int argc, char **argv)
 
 #define MAX_VIRTIO_CONSOLES 1
 
+#define RHEL_MAX_CPUS 384
+
 static const char *data_dir[16];
 static int data_dir_idx;
 const char *bios_name = NULL;
@@ -1339,6 +1341,20 @@ static MachineClass *find_default_machine(GSList *machines)
     return NULL;
 }
 
+/* Maximum number of CPUs limited for Red Hat Enterprise Linux */
+static void limit_max_cpus_in_machines(void)
+{
+    GSList *el, *machines = object_class_get_list(TYPE_MACHINE, false);
+
+    for (el = machines; el; el = el->next) {
+        MachineClass *mc = el->data;
+
+        if (mc->max_cpus > RHEL_MAX_CPUS) {
+            mc->max_cpus = RHEL_MAX_CPUS;
+        }
+    }
+}
+
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
     ObjectProperty *prop;
@@ -3857,6 +3873,8 @@ int main(int argc, char **argv, char **envp)
                      "mutually exclusive");
         exit(EXIT_FAILURE);
     }
+    /* Maximum number of CPUs limited for Red Hat Enterprise Linux */
+    limit_max_cpus_in_machines();
 
     configure_rtc(qemu_find_opts_singleton("rtc"));
 
-- 
2.21.0