Since KVM_MAX_VCPUS is currently defined to 1024 for x86 as shown in arch/x86/include/asm/kvm_host.h, update QEMU limits to the same number.
In case KVM could not support the specified number of vcpus, QEMU would return the following error message: qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (xxx): Invalid argument Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> --- Changes from V1: (https://lore.kernel.org/all/ynkdgsii1vfvx...@redhat.com/T/) * Bump from 512 to KVM_MAX_VCPUS (per Igor's suggestion) Note: From the last discussion, Daniel mentioned that SMBIO 2.1 tables might cause overflow at approx 720 CPUs, and it might require using the SMBIO 3.0 entry point. Also, we might need to change the default for the x86 machine type to SMBIO 3.0. However, I do not know the status of this. Thank you, Suravee hw/i386/pc_q35.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c index f02919d92c..e7dc226bd5 100644 --- a/hw/i386/pc_q35.c +++ b/hw/i386/pc_q35.c @@ -370,7 +370,7 @@ static void pc_q35_machine_options(MachineClass *m) machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE); machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE); machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE); - m->max_cpus = 288; + m->max_cpus = 1024; } static void pc_q35_8_1_machine_options(MachineClass *m) -- 2.34.1
