[PATCH] KVM: PPC: Add KVM_CAP_NR_VCPUS and KVM_CAP_MAX_VCPUS

[Matt Evans <matt@ozlabs.org>]

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>
---

Alex: For when you're back in civilisation -- the kvmtool/PPC stuff will be
limited to 4 VCPUs until the kernel returns something for these caps.

Cheers, Matt

 arch/powerpc/kvm/powerpc.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 7c7220c..3f7219d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -245,6 +245,21 @@ int kvm_dev_ioctl_check_extension(long ext)
 			r = 2;
 		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;
-- 
1.7.0.4