KVM vCPU creation is done once during the initialization of the VM when Qemu threads are spawned. This is common to all the architectures.
Hot-unplug of vCPU results in destruction of the vCPU objects in QOM but the KVM vCPU objects in the Host KVM are not destroyed and their representative KVM vCPU objects/context in Qemu are parked. Refactor common logic so that some APIs could be reused by vCPU Hotplug code. Signed-off-by: Salil Mehta <salil.me...@huawei.com> --- accel/kvm/kvm-all.c | 61 ++++++++++++++++++++++++++++++++++---------- include/sysemu/kvm.h | 2 ++ 2 files changed, 49 insertions(+), 14 deletions(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index ff1578bb32..57889c5f6c 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -137,6 +137,7 @@ static QemuMutex kml_slots_lock; #define kvm_slots_unlock() qemu_mutex_unlock(&kml_slots_lock) static void kvm_slot_init_dirty_bitmap(KVMSlot *mem); +static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id); static inline void kvm_resample_fd_remove(int gsi) { @@ -320,11 +321,51 @@ err: return ret; } +void kvm_park_vcpu(CPUState *cpu) +{ + unsigned long vcpu_id = cpu->cpu_index; + struct KVMParkedVcpu *vcpu; + + vcpu = g_malloc0(sizeof(*vcpu)); + vcpu->vcpu_id = vcpu_id; + vcpu->kvm_fd = cpu->kvm_fd; + QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); +} + +int kvm_create_vcpu(CPUState *cpu) +{ + unsigned long vcpu_id = cpu->cpu_index; + KVMState *s = kvm_state; + int ret; + + DPRINTF("kvm_create_vcpu\n"); + + /* check if the KVM vCPU already exist but is parked */ + ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu)); + if (ret > 0) { + goto found; + } + + /* create a new KVM vCPU */ + ret = kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); + if (ret < 0) { + return ret; + } + +found: + cpu->vcpu_dirty = true; + cpu->kvm_fd = ret; + cpu->kvm_state = s; + cpu->dirty_pages = 0; + cpu->throttle_us_per_full = 0; + + return 0; +} + static int do_kvm_destroy_vcpu(CPUState *cpu) { KVMState *s = kvm_state; long mmap_size; - struct KVMParkedVcpu *vcpu = NULL; int ret = 0; DPRINTF("kvm_destroy_vcpu\n"); @@ -353,10 +394,7 @@ static int do_kvm_destroy_vcpu(CPUState *cpu) } } - vcpu = g_malloc0(sizeof(*vcpu)); - vcpu->vcpu_id = kvm_arch_vcpu_id(cpu); - vcpu->kvm_fd = cpu->kvm_fd; - QLIST_INSERT_HEAD(&kvm_state->kvm_parked_vcpus, vcpu, node); + kvm_park_vcpu(cpu); err: return ret; } @@ -384,7 +422,7 @@ static int kvm_get_vcpu(KVMState *s, unsigned long vcpu_id) } } - return kvm_vm_ioctl(s, KVM_CREATE_VCPU, (void *)vcpu_id); + return -1; } int kvm_init_vcpu(CPUState *cpu, Error **errp) @@ -395,19 +433,14 @@ int kvm_init_vcpu(CPUState *cpu, Error **errp) trace_kvm_init_vcpu(cpu->cpu_index, kvm_arch_vcpu_id(cpu)); - ret = kvm_get_vcpu(s, kvm_arch_vcpu_id(cpu)); + ret = kvm_create_vcpu(cpu); if (ret < 0) { - error_setg_errno(errp, -ret, "kvm_init_vcpu: kvm_get_vcpu failed (%lu)", + error_setg_errno(errp, -ret, + "kvm_init_vcpu: kvm_create_vcpu failed (%lu)", kvm_arch_vcpu_id(cpu)); goto err; } - cpu->kvm_fd = ret; - cpu->kvm_state = s; - cpu->vcpu_dirty = true; - cpu->dirty_pages = 0; - cpu->throttle_us_per_full = 0; - mmap_size = kvm_ioctl(s, KVM_GET_VCPU_MMAP_SIZE, 0); if (mmap_size < 0) { ret = mmap_size; diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h index ee9025f8e9..17919567a8 100644 --- a/include/sysemu/kvm.h +++ b/include/sysemu/kvm.h @@ -464,6 +464,8 @@ void kvm_set_sigmask_len(KVMState *s, unsigned int sigmask_len); int kvm_physical_memory_addr_from_host(KVMState *s, void *ram_addr, hwaddr *phys_addr); +int kvm_create_vcpu(CPUState *cpu); +void kvm_park_vcpu(CPUState *cpu); #endif /* NEED_CPU_H */ -- 2.34.1