KVM: PPC: Add KVM_CAP_NR_VCPUS and KVM_CAP_MAX_VCPUS

PPC KVM lacks these two capabilities, and as such a userland system must assume
a max of 4 VCPUs (following api.txt).  With these, a userland can determine
a more realistic limit.

Signed-off-by: Matt Evans <matt@ozlabs.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 25171037a36c..f4380cb264e0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -249,6 +249,22 @@ int kvm_dev_ioctl_check_extension(long ext)
                 r = cpu_has_feature(CPU_FTR_ARCH_206) ? 1 : 0;
                 break;
 #endif
+        case KVM_CAP_NR_VCPUS:
+                /*
+                 * Recommending a number of CPUs is somewhat arbitrary; we
+                 * return the number of present CPUs for -HV (since a host
+                 * will have secondary threads "offline"), and for other KVM
+                 * implementations just count online CPUs.
+                 */
+#ifdef CONFIG_KVM_BOOK3S_64_HV
+                r = num_present_cpus();
+#else
+                r = num_online_cpus();
+#endif
+                break;
+        case KVM_CAP_MAX_VCPUS:
+                r = KVM_MAX_VCPUS;
+                break;
         default:
                 r = 0;
                 break;