Intel Processor Tracing (PT) Exposed to KVM Guest

[Zion Yang]

Hi,

 

I am trying to do Intel Processor Tracing (Intel PT) from within a KVM guest VM started with `-cpu host`. However, I cannot find the `/sys/devices/intel_pt` device in the VM, which exists on the host. I compared the output of `cat /proc/cpuinfo` between the host and the guest and find that `flag: intel_pt` is missing from the guest while it exists in the host.

 

I am aware of the related thread from the qemu-devel list

[PATCH v2 6/8] target/i386/intel-pt: Enable host pass through of Intel P

But after applying the patch I still can’t get it working. The flag and the device are still missing from within the guest.

 

Can another give a pointer? Related infos are attached below:

 

QEMU version: 7.1.0

CPU: Intel i9 12900k

Host OS:ubuntu 22.04

Guest OS: mainline Linux kernel 5.10

 

Thanks!

Regards,

- Zion