libvirt uses "none" machine type to test KVM availability. Before this change, QEMU used to pass 0 as machine type when calling KVM_CREATE_VM. The kernel documentation says: > On arm64, the physical address size for a VM (IPA Size limit) is > limited to 40bits by default. The limit can be configured if the host > supports the extension KVM_CAP_ARM_VM_IPA_SIZE. When supported, use > KVM_VM_TYPE_ARM_IPA_SIZE(IPA_Bits) to set the size in the machine type > identifier, where IPA_Bits is the maximum width of any physical > address used by the VM. The IPA_Bits is encoded in bits[7-0] of the > machine type identifier. > > e.g, to configure a guest to use 48bit physical address size:: > > vm_fd = ioctl(dev_fd, KVM_CREATE_VM, KVM_VM_TYPE_ARM_IPA_SIZE(48)); > > The requested size (IPA_Bits) must be: > > == ========================================================= > 0 Implies default size, 40bits (for backward compatibility) > N Implies N bits, where N is a positive integer such that, > 32 <= N <= Host_IPA_Limit > == ========================================================= > Host_IPA_Limit is the maximum possible value for IPA_Bits on the host > and is dependent on the CPU capability and the kernel configuration. > The limit can be retrieved using KVM_CAP_ARM_VM_IPA_SIZE of the > KVM_CHECK_EXTENSION ioctl() at run-time. > > Creation of the VM will fail if the requested IPA size (whether it is > implicit or explicit) is unsupported on the host. https://docs.kernel.org/virt/kvm/api.html#kvm-create-vm So if Host_IPA_Limit < 40, such KVM_CREATE_VM will fail, and libvirt incorrectly thinks KVM is not available. This actually happened on M2 MacBook Air. Fix this by specifying 32 for IPA_Bits as any arm64 system should support the value according to the documentation. Signed-off-by: Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> --- Resending due to inactivity. accel/kvm/kvm-all.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 373d876c05..3bd362e346 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -2458,7 +2458,11 @@ static int kvm_init(MachineState *ms) KVMState *s; const KVMCapabilityInfo *missing_cap; int ret; +#ifdef TARGET_AARCH64 + int type = 32; +#else int type = 0; +#endif uint64_t dirty_log_manual_caps; qemu_mutex_init(&kml_slots_lock); -- 2.41.0
