[Qemu-discuss] How to enable KVM processor tracing?

[Han Han]

Hello,
>From qemu-2.12 release note( https://wiki.qemu.org/ChangeLog/2.12#KVM_2 ),
I find that qemu supports processor tracing now. But it doesn't say which
option can enable that. Do you have any ideas?
I tried kvm-hint-dedicated=on but it didn't work:
1. My host: debian 9, kernel-4.16.0-2-amd64 && qemu-kvm-2.12+dfsg-3,
Broadwell cpu, supports perf intel_pt event.

2.  Start a VM with following qemu cmdline:
# kvm -m 2048 -nic user,ipv6=off,model=e1000e,mac=52:54:98:76:54:32 -cpu
Broadwell,vme=on,ss=on,f16c=on,rdrand=on,hypervisor=on,arat=on,tsc_adjust=on,xsaveopt=on,pdpe1gb=on,abm=on,kvm-hint-dedicated=on
-spice
port=5900,addr=127.0.0.1,disable-ticketing,image-compression=off,seamless-migration=on
/var/lib/libvirt/images/generic.qcow2

My VM: fedora 28, kernel-4.16.13-300

Try to run perf:
# perf record -C 0 -e intel_pt -a sleep 1
event syntax error: 'intel_pt'
                     \___ Cannot find PMU `intel_pt'. Missing kernel
support?
Run 'perf list' for a list of valid events

 Usage: perf record [<options>] [<command>]
    or: perf record [<options>] -- <command> [<options>]

    -e, --event <event>   event selector. use 'perf list' to list available
events

-- 
Best regards,
-----------------------------------
Han Han
Quality Engineer
Redhat.

Email: address@hidden
Phone: +861065339333