On Mon, Aug 2, 2021 at 3:21 PM Krish Sadhukhan
[off-list ref] wrote:

On 8/2/21 9:39 AM, Paolo Bonzini wrote:

quoted

On 02/08/21 18:34, Sean Christopherson wrote:

quoted

On Mon, Aug 02, 2021, Paolo Bonzini wrote:

quoted

On 21/06/21 22:43, Krish Sadhukhan wrote:

quoted

With this patch KVM entry and exit tracepoints will
show "guest_mode = 0" if it is a guest and "guest_mode = 1" if it is a
nested guest.

What about adding a "(nested)" suffix for L2, and nothing for L1?

That'd work too, though it would be nice to get vmcx12 printed as
well so that
it would be possible to determine which L2 is running without having
to cross-
reference other tracepoints.

Yes, it would be nice but it would also clutter the output a bit.
It's like what we have already in kvm_inj_exception:

        TP_printk("%s (0x%x)",
                  __print_symbolic(__entry->exception,
kvm_trace_sym_exc),
                  /* FIXME: don't print error_code if not present */
                  __entry->has_error ? __entry->error_code : 0)

It could be done with a trace-cmd plugin, but that creates other
issues since
it essentially forces the tracepoints to have a stable API.

Paolo

Also, the vmcs/vmcb address is vCPU-specific, so if L2 runs on 10 vCPUs,
traces will show 10 different addresses for the same L2 and it's not
convenient on a cloud host where hundreds of L1s and L2s run.

The vmcx02 address is vCPU-specific. However, Sean asked for the
vmcx12 address, which is a GPA that is common across all vCPUs.