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authorGreg Kurz <groug@kaod.org>2017-09-21 18:01:02 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2017-10-02 14:38:06 +0200
commit11748ba72ea4fc03e975aa5f5d876b5b0902e356 (patch)
treea240ffa568d52cd8b529ace7c90e78c4602eaa57 /accel
parent62dd4edaaf859b60f74a51f2a526d4d3d85d0248 (diff)
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kvm: check KVM_CAP_NR_VCPUS with kvm_vm_check_extension()
On a modern server-class ppc host with the following CPU topology: Architecture: ppc64le Byte Order: Little Endian CPU(s): 32 On-line CPU(s) list: 0,8,16,24 Off-line CPU(s) list: 1-7,9-15,17-23,25-31 Thread(s) per core: 1 If both KVM PR and KVM HV loaded and we pass: -machine pseries,accel=kvm,kvm-type=PR -smp 8 We expect QEMU to warn that this exceeds the number of online CPUs: Warning: Number of SMP cpus requested (8) exceeds the recommended cpus supported by KVM (4) Warning: Number of hotpluggable cpus requested (8) exceeds the recommended cpus supported by KVM (4) but nothing is printed... This happens because on ppc the KVM_CAP_NR_VCPUS capability is VM specific ndreally depends on the KVM type, but we currently use it as a global capability. And KVM returns a fallback value based on KVM HV being present. Maybe KVM on POWER shouldn't presume anything as long as it doesn't have a VM, but in all cases, we should call KVM_CREATE_VM first and use KVM_CAP_NR_VCPUS as a VM capability. This patch hence changes kvm_recommended_vcpus() accordingly and moves the sanity checking of smp_cpus after the VM creation. It is okay for the other archs that also implement KVM_CAP_NR_VCPUS, ie, mips, s390, x86 and arm, because they don't depend on the VM being created or not. Signed-off-by: Greg Kurz <groug@kaod.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Thomas Huth <thuth@redhat.com> Message-Id: <150600966286.30533.10909862523552370889.stgit@bahia.lan> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'accel')
-rw-r--r--accel/kvm/kvm-all.c43
1 files changed, 22 insertions, 21 deletions
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f54a337..90c88b5 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1440,7 +1440,7 @@ static void kvm_irqchip_create(MachineState *machine, KVMState *s)
*/
static int kvm_recommended_vcpus(KVMState *s)
{
- int ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS);
+ int ret = kvm_vm_check_extension(s, KVM_CAP_NR_VCPUS);
return (ret) ? ret : 4;
}
@@ -1530,26 +1530,6 @@ static int kvm_init(MachineState *ms)
s->nr_slots = 32;
}
- /* check the vcpu limits */
- soft_vcpus_limit = kvm_recommended_vcpus(s);
- hard_vcpus_limit = kvm_max_vcpus(s);
-
- while (nc->name) {
- if (nc->num > soft_vcpus_limit) {
- warn_report("Number of %s cpus requested (%d) exceeds "
- "the recommended cpus supported by KVM (%d)",
- nc->name, nc->num, soft_vcpus_limit);
-
- if (nc->num > hard_vcpus_limit) {
- fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
- "the maximum cpus supported by KVM (%d)\n",
- nc->name, nc->num, hard_vcpus_limit);
- exit(1);
- }
- }
- nc++;
- }
-
kvm_type = qemu_opt_get(qemu_get_machine_opts(), "kvm-type");
if (mc->kvm_type) {
type = mc->kvm_type(kvm_type);
@@ -1584,6 +1564,27 @@ static int kvm_init(MachineState *ms)
}
s->vmfd = ret;
+
+ /* check the vcpu limits */
+ soft_vcpus_limit = kvm_recommended_vcpus(s);
+ hard_vcpus_limit = kvm_max_vcpus(s);
+
+ while (nc->name) {
+ if (nc->num > soft_vcpus_limit) {
+ warn_report("Number of %s cpus requested (%d) exceeds "
+ "the recommended cpus supported by KVM (%d)",
+ nc->name, nc->num, soft_vcpus_limit);
+
+ if (nc->num > hard_vcpus_limit) {
+ fprintf(stderr, "Number of %s cpus requested (%d) exceeds "
+ "the maximum cpus supported by KVM (%d)\n",
+ nc->name, nc->num, hard_vcpus_limit);
+ exit(1);
+ }
+ }
+ nc++;
+ }
+
missing_cap = kvm_check_extension_list(s, kvm_required_capabilites);
if (!missing_cap) {
missing_cap =