On Tue, 30 Jul 2024 16:24:32 +0800
Liju-clr Chen [off-list ref] wrote:

From: Liju Chen <redacted>

Add tracepoints for hypervisor calls and VCPU exit reasons in GenieZone
driver. It aids performance debugging by providing more information
about hypervisor operations and VCPU behavior.

Command Usage:
echo geniezone:* >> /sys/kernel/tracing/set_event
echo 1 > /sys/kernel/tracing/tracing_on
echo 0 > /sys/kernel/tracing/tracing_on
cat /sys/kernel/tracing/trace

For example:
crosvm_vcpu0-4874    [007] .....    94.757349: mtk_hypcall_enter: id=0xfb001005
crosvm_vcpu0-4874    [007] .....    94.760902: mtk_hypcall_leave: id=0xfb001005 invalid=0
crosvm_vcpu0-4874    [007] .....    94.760902: mtk_vcpu_exit: vcpu exit_reason=IRQ(0x92920003)

This example tracks a hypervisor function call by an ID (`0xbb001005`)
from initiation to termination, which is supported (invalid=0). A vCPU
exit is triggered by an Interrupt Request (IRQ) (exit reason: 0x92920003).

/* VM exit reason */
enum {
	GZVM_EXIT_UNKNOWN = 0x92920000,
	GZVM_EXIT_MMIO = 0x92920001,
	GZVM_EXIT_HYPERCALL = 0x92920002,
	GZVM_EXIT_IRQ = 0x92920003,
	GZVM_EXIT_EXCEPTION = 0x92920004,
	GZVM_EXIT_DEBUG = 0x92920005,
	GZVM_EXIT_FAIL_ENTRY = 0x92920006,
	GZVM_EXIT_INTERNAL_ERROR = 0x92920007,
	GZVM_EXIT_SYSTEM_EVENT = 0x92920008,
	GZVM_EXIT_SHUTDOWN = 0x92920009,
	GZVM_EXIT_GZ = 0x9292000a,
};

Signed-off-by: Yi-De Wu <redacted>
Signed-off-by: Liju Chen <redacted>

From a tracing POV, I don't see any issues with this patch.

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

---
 arch/arm64/geniezone/vm.c          |  4 ++
 drivers/virt/geniezone/gzvm_vcpu.c |  3 ++
 include/trace/events/geniezone.h   | 84 ++++++++++++++++++++++++++++++
 3 files changed, 91 insertions(+)
 create mode 100644 include/trace/events/geniezone.h