From 0b1b1dfd52a67f4f09a18cb82337199bc90ad7fb Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Mon, 9 May 2016 18:13:37 +0200 Subject: kvm: introduce KVM_MAX_VCPU_ID The KVM_MAX_VCPUS define provides the maximum number of vCPUs per guest, and also the upper limit for vCPU ids. This is okay for all archs except PowerPC which can have higher ids, depending on the cpu/core/thread topology. In the worst case (single threaded guest, host with 8 threads per core), it limits the maximum number of vCPUS to KVM_MAX_VCPUS / 8. This patch separates the vCPU numbering from the total number of vCPUs, with the introduction of KVM_MAX_VCPU_ID, as the maximal valid value for vCPU ids plus one. The corresponding KVM_CAP_MAX_VCPU_ID allows userspace to validate vCPU ids before passing them to KVM_CREATE_VCPU. This patch only implements KVM_MAX_VCPU_ID with a specific value for PowerPC. Other archs continue to return KVM_MAX_VCPUS instead. Suggested-by: Radim Krcmar Signed-off-by: Greg Kurz Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini --- include/uapi/linux/kvm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index a7f1f8032ec1..05ebf475104c 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -865,6 +865,7 @@ struct kvm_ppc_smmu_info { #define KVM_CAP_SPAPR_TCE_64 125 #define KVM_CAP_ARM_PMU_V3 126 #define KVM_CAP_VCPU_ATTRIBUTES 127 +#define KVM_CAP_MAX_VCPU_ID 128 #ifdef KVM_CAP_IRQ_ROUTING -- cgit v1.2.3-58-ga151