Patchwork [44/50] KVM: PPC: Add KVM_CAP_NR_VCPUS and KVM_CAP_MAX_VCPUS

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Submitter Alexander Graf
Date Jan. 4, 2012, 1:10 a.m.
Message ID <1325639448-9494-45-git-send-email-agraf@suse.de>
Download mbox | patch
Permalink /patch/134141/
State New
Headers show

Comments

Alexander Graf - Jan. 4, 2012, 1:10 a.m.
From: 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>
Signed-off-by: Alexander Graf <agraf@suse.de>
---
 arch/powerpc/kvm/powerpc.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)

Patch

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 9483d20..64c738d 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -248,6 +248,22 @@  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;