Add a Kconfig entry to set the maximum number of vCPUs per KVM guest and set the default value to 4096 when MAXSMP is enabled. Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> Signed-off-by: Kyle Meyer <kyle.meyer@xxxxxxx> --- v2 -> v3: Default KVM_MAX_VCPUS to 1024 when CONFIG_KVM_MAX_NR_VCPUS is not defined. This prevents build failures in arch/x86/events/intel/core.c and drivers/vfio/vfio_main.c when KVM is disabled. arch/x86/include/asm/kvm_host.h | 4 ++++ arch/x86/kvm/Kconfig | 11 +++++++++++ 2 files changed, 15 insertions(+) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 3bc146dfd38d..cd27e0a00765 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -39,7 +39,11 @@ #define __KVM_HAVE_ARCH_VCPU_DEBUGFS +#ifdef CONFIG_KVM_MAX_NR_VCPUS +#define KVM_MAX_VCPUS CONFIG_KVM_MAX_NR_VCPUS +#else #define KVM_MAX_VCPUS 1024 +#endif /* * In x86, the VCPU ID corresponds to the APIC ID, and APIC IDs diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig index 89ca7f4c1464..e730e8255e22 100644 --- a/arch/x86/kvm/Kconfig +++ b/arch/x86/kvm/Kconfig @@ -141,4 +141,15 @@ config KVM_XEN config KVM_EXTERNAL_WRITE_TRACKING bool +config KVM_MAX_NR_VCPUS + int "Maximum number of vCPUs per KVM guest" + depends on KVM + range 1024 4096 + default 4096 if MAXSMP + default 1024 + help + Set the maximum number of vCPUs per KVM guest. Larger values will increase + the memory footprint of each KVM guest, regardless of how many vCPUs are + configured. + endif # VIRTUALIZATION -- 2.26.2
