Hello Arnabjyoti, Sean, and everyone, I'm having a similiar but slightly differnt issue about the rdtsc in KVM. I want to obtain the timestamp counter of physical/host machine inside the VMs. Acccording to the previous threads, I know I need to disable the offsetting, VM exit, and scaling. I specify the correspoding parameters in the qemu arguments. The booting command is listed below: qemu-system-x86_64 -m 10240 -smp 4 -chardev socket,id=SOCKSYZ,server=on,nowait,host=localhost,port=3258 -mon chardev=SOCKSYZ,mode=control -display none -serial stdio -device virtio-rng-pci -enable-kvm -cpu host,migratable=off,tsc=on,rdtscp=on,vmx-tsc-offset=off,vmx-rdtsc-exit=off,tsc-scale=off,tsc-adjust=off,vmx-rdtscp-exit=off -netdev bridge,id=hn40 -device virtio-net,netdev=hn40,mac=e6:c8:ff:09:76:38 -hda XXX -kernel XXX -append "root=/dev/sda console=ttyS0" But the rdtsc still returns the adjusted tsc. The vmxcap script shows the TSC settings as below: Use TSC offsetting no RDTSC exiting no Enable RDTSCP no TSC scaling yes I would really appreciate it if anyone can tell me whether and how I can get the tsc of physical machine insdie the VM. Thanks a lot.
