Single Step Example on Xen 4.6.1

[00150891]

Hi,

is the singlestep-event-example not running on Xen (using 4.6.1)?

I am getting the following error, when running it: VMI_ERROR: xen_start_single_step error: no system support for event type
Also setting up a similar event manually or with the makro leads to the same result.

Xen-events are enabled in by configuration.

I am glad if anyone can give me a hint :)

[Tamas K Lengyel]

It depends on the hardware. It seems you have a CPU which doesn't have
Monitor Trap Flag capability. Or at least Xen thinks that way, so
singlestepping is disabled on your machine.

Tamas

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[00150891]

Is there a way to tell if my CPU doesn't have a Monitor Trap Flag?
According to /proc/cpuinfo the flags "monitor" as well as "hypervisor" are enabled on my machine.

[Tamas K Lengyel]

Xen checks the following bit in the MSR_IA32_VMX_PROCBASED_CTLS MSR of
the cpu to determine if singlestep is supported:

#define CPU_BASED_MONITOR_TRAP_FLAG 0x08000000

[00150891]

Thanks for the information! Got it running,
Cheers

[Tamas K Lengyel]

Would you mind sharing what you did to get it working?

Thanks!

[00150891]

I switched my machine. Intel Core 2 Duo (with VT-x enabled) seems to be too old. On an i5 there were no troubles getting everything running.