diff options
| -rw-r--r-- | Documentation/virtual/kvm/api.txt | 11 | ||||
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 3 | ||||
| -rw-r--r-- | arch/x86/kvm/x86.c | 3 | ||||
| -rw-r--r-- | include/linux/kvm.h | 3 |
4 files changed, 16 insertions, 4 deletions
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index b0e4b9cd6a66..75cd8fba0cde 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -175,10 +175,17 @@ Parameters: vcpu id (apic id on x86) Returns: vcpu fd on success, -1 on error This API adds a vcpu to a virtual machine. The vcpu id is a small integer -in the range [0, max_vcpus). You can use KVM_CAP_NR_VCPUS of the -KVM_CHECK_EXTENSION ioctl() to determine the value for max_vcpus at run-time. +in the range [0, max_vcpus). + +The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of +the KVM_CHECK_EXTENSION ioctl() at run-time. +The maximum possible value for max_vcpus can be retrieved using the +KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. + If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 cpus max. +If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is +same as the value returned from KVM_CAP_NR_VCPUS. On powerpc using book3s_hv mode, the vcpus are mapped onto virtual threads in one or more virtual CPU cores. (This is because the diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index dd51c83aa5de..c00ec28e7147 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -26,7 +26,8 @@ #include <asm/mtrr.h> #include <asm/msr-index.h> -#define KVM_MAX_VCPUS 64 +#define KVM_MAX_VCPUS 254 +#define KVM_SOFT_MAX_VCPUS 64 #define KVM_MEMORY_SLOTS 32 /* memory slots that does not exposed to userspace */ #define KVM_PRIVATE_MEM_SLOTS 4 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2b76ae3cb501..41dfebea6218 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2086,6 +2086,9 @@ int kvm_dev_ioctl_check_extension(long ext) r = !kvm_x86_ops->cpu_has_accelerated_tpr(); break; case KVM_CAP_NR_VCPUS: + r = KVM_SOFT_MAX_VCPUS; + break; + case KVM_CAP_MAX_VCPUS: r = KVM_MAX_VCPUS; break; case KVM_CAP_NR_MEMSLOTS: diff --git a/include/linux/kvm.h b/include/linux/kvm.h index aace6b8691a2..206979877888 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -463,7 +463,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_VAPIC 6 #define KVM_CAP_EXT_CPUID 7 #define KVM_CAP_CLOCKSOURCE 8 -#define KVM_CAP_NR_VCPUS 9 /* returns max vcpus per vm */ +#define KVM_CAP_NR_VCPUS 9 /* returns recommended max vcpus per vm */ #define KVM_CAP_NR_MEMSLOTS 10 /* returns max memory slots per vm */ #define KVM_CAP_PIT 11 #define KVM_CAP_NOP_IO_DELAY 12 @@ -553,6 +553,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_SPAPR_TCE 63 #define KVM_CAP_PPC_SMT 64 #define KVM_CAP_PPC_RMA 65 +#define KVM_CAP_MAX_VCPUS 66 /* returns max vcpus per vm */ #define KVM_CAP_S390_GMAP 71 #ifdef KVM_CAP_IRQ_ROUTING |