Hi Vitaly, 2018-05-16 23:21 GMT+08:00 Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>: > Changes since v3 [Radim Krcmar]: > - PATCH2 fixing 'HV_GENERIC_SET_SPARCE_4K' typo added. > - PATCH5 introducing kvm_make_vcpus_request_mask() API added. > - Fix undefined behavior for hv->vp_index >= 64. > - Merge kvm_hv_flush_tlb() and kvm_hv_flush_tlb_ex() > - For -ex case preload all banks with a single kvm_read_guest(). > > Description: > > This is both a new feature and a bugfix. > > Bugfix description: > > It was found that Windows 2016 guests on KVM crash when they have > 64 > vCPUs, non-flat topology (>1 core/thread per socket; in case it has >64 > sockets Windows just ignores vCPUs above 64) and Hyper-V enlightenments We try the below command line, the Windows 2016 guest successfully to login and there are 80 vCPUs can be observed in the guest w/o the patchset, why you mentioned the crash and ignore? /usr/local/bin/qemu-system-x86_64 -machine pc-i440fx-rhel7.3.0 -m 8192 -smp 80,sockets=2,cores=40,threads=1 -device ide-drive,bus=ide.0,drive=test -drive id=test,if=none,file=/instanceimage/359b18ab-05bb-460d-9b53-89505bca68ed/359b18ab-05bb-460d-9b53-89505bca68ed_vda_1.qcow2 -net nic,model=virtio -net user -monitor stdio -usb -usbdevice tablet --enable-kvm --cpu host -vnc 0.0.0.0:2 Regards, Wanpeng Li