2018-05-18 19:19 GMT+08:00 Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>: > Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> writes: > >> Wanpeng Li <kernellwp@xxxxxxxxx> writes: >> >>> 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 >> >> Crash happens when you manifest yourself as Hyper-V, you can do this by >> adding any 'hv-*' feature (e.g. try '-cpu host,hv_vpindex'). > > Oh, and the 'ignore' happens when you pass more than 64 sockets > (somthing like "-smp 128,sockets=128,cores=1,threads=1") -- and this > happens regardless of Hyper-V enlightenments. But I guess it's just > because Windows doesn't support more than 64 sockets. Is there an option in the guest to avoid to check pvtlb support in hyperv? Regards, Wanpeng Li
