[PATCH v1 1/3] KVM: arm64: Add ESR class to the hyp_enter hyp event

[Vincent Donnefort <vdonnefort@google.com>]

Give a more detailed reason the hyp has been entered by reading the ESR
class when relevant (that is on trap). Encode the ESR class directly
into the existing reason field.

To distinguish between a trap from host and from guest, add a "from="
field, which has 3 possibilities: "host", "vcpu" or "firmware". This
value can be deducted based on the existing vcpu field.

Finally, add a "to=" field to the hyp_exit event to mirror "hyp_enter".

Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
---
 arch/arm64/include/asm/kvm_hypevents.h | 21 ++++++-----
 arch/arm64/kvm/hyp/nvhe/hyp-main.c     |  7 +---
 arch/arm64/kvm/hyp/nvhe/psci-relay.c   |  2 +-
 arch/arm64/kvm/hyp/nvhe/switch.c       |  6 ++-
 arch/arm64/kvm/hyp_trace.c             | 52 ++++++++++++++++++++------
 5 files changed, 59 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hypevents.h b/arch/arm64/include/asm/kvm_hypevents.h
index 5f6e6789d121..96985c93a15e 100644
--- a/arch/arm64/include/asm/kvm_hypevents.h
+++ b/arch/arm64/include/asm/kvm_hypevents.h
@@ -10,15 +10,10 @@
 #ifndef __HYP_ENTER_EXIT_REASON
 #define __HYP_ENTER_EXIT_REASON
 enum hyp_enter_exit_reason {
-	HYP_REASON_SMC,
-	HYP_REASON_HVC,
-	HYP_REASON_SYS,
+	HYP_REASON_SMC = ESR_ELx_EC_MAX + 1,
 	HYP_REASON_PSCI,
-	HYP_REASON_HOST_ABORT,
-	HYP_REASON_GUEST_EXIT,
-	HYP_REASON_ERET_HOST,
-	HYP_REASON_ERET_GUEST,
-	HYP_REASON_UNKNOWN	/* Must be last */
+	HYP_REASON_IRQ,
+	HYP_REASON_ERET,
 };
 #endif
 
@@ -32,7 +27,10 @@ HYP_EVENT(hyp_enter,
 		__entry->reason = reason;
 		__entry->vcpu = __tracing_get_vcpu_pid(host_ctxt);
 	),
-	HE_PRINTK("reason=%s vcpu=%d", __hyp_enter_exit_reason_str(__entry->reason), __entry->vcpu)
+	HE_PRINTK("from=%s reason=%s vcpu=%d",
+		  __hyp_enter_exit_str(__entry->reason, __entry->vcpu),
+		  __hyp_enter_exit_reason_str(__entry->reason),
+		  __entry->vcpu)
 );
 
 HYP_EVENT(hyp_exit,
@@ -45,7 +43,10 @@ HYP_EVENT(hyp_exit,
 		__entry->reason = reason;
 		__entry->vcpu = __tracing_get_vcpu_pid(host_ctxt);
 	),
-	HE_PRINTK("reason=%s vcpu=%d", __hyp_enter_exit_reason_str(__entry->reason), __entry->vcpu)
+	HE_PRINTK("to=%s reason=%s vcpu=%d",
+		  __hyp_enter_exit_str(__entry->reason, __entry->vcpu),
+		  __hyp_enter_exit_reason_str(__entry->reason),
+		  __entry->vcpu)
 );
 
 HYP_EVENT(selftest,
diff --git a/arch/arm64/kvm/hyp/nvhe/hyp-main.c b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
index ac64a036b0a9..76d08c503dc0 100644
--- a/arch/arm64/kvm/hyp/nvhe/hyp-main.c
+++ b/arch/arm64/kvm/hyp/nvhe/hyp-main.c
@@ -1112,23 +1112,20 @@ void handle_trap(struct kvm_cpu_context *host_ctxt)
 {
 	u64 esr = read_sysreg_el2(SYS_ESR);
 
+	trace_hyp_enter(host_ctxt, ESR_ELx_EC(esr));
 
 	switch (ESR_ELx_EC(esr)) {
 	case ESR_ELx_EC_HVC64:
-		trace_hyp_enter(host_ctxt, HYP_REASON_HVC);
 		handle_host_hcall(host_ctxt);
 		break;
 	case ESR_ELx_EC_SMC64:
-		trace_hyp_enter(host_ctxt, HYP_REASON_SMC);
 		handle_host_smc(host_ctxt);
 		break;
 	case ESR_ELx_EC_IABT_LOW:
 	case ESR_ELx_EC_DABT_LOW:
-		trace_hyp_enter(host_ctxt, HYP_REASON_HOST_ABORT);
 		handle_host_mem_abort(host_ctxt);
 		break;
 	case ESR_ELx_EC_SYS64:
-		trace_hyp_enter(host_ctxt, HYP_REASON_SYS);
 		if (handle_host_mte(esr))
 			break;
 		fallthrough;
@@ -1136,5 +1133,5 @@ void handle_trap(struct kvm_cpu_context *host_ctxt)
 		BUG();
 	}
 
-	trace_hyp_exit(host_ctxt, HYP_REASON_ERET_HOST);
+	trace_hyp_exit(host_ctxt, HYP_REASON_ERET);
 }
diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
index e20db999e328..c771c1d150c4 100644
--- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c
+++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
@@ -213,7 +213,7 @@ static void __noreturn __kvm_host_psci_cpu_entry(unsigned long pc, unsigned long
 	write_sysreg_el1(INIT_SCTLR_EL1_MMU_OFF, SYS_SCTLR);
 	write_sysreg(INIT_PSTATE_EL1, SPSR_EL2);
 
-	trace_hyp_exit(host_ctxt, HYP_REASON_PSCI);
+	trace_hyp_exit(host_ctxt, HYP_REASON_ERET);
 	__host_enter(host_ctxt);
 }
 
diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
index 7318e3e6a5f3..cf4de8287b97 100644
--- a/arch/arm64/kvm/hyp/nvhe/switch.c
+++ b/arch/arm64/kvm/hyp/nvhe/switch.c
@@ -324,13 +324,15 @@ int __kvm_vcpu_run(struct kvm_vcpu *vcpu)
 	__debug_switch_to_guest(vcpu);
 
 	do {
-		trace_hyp_exit(host_ctxt, HYP_REASON_ERET_GUEST);
+		trace_hyp_exit(host_ctxt, HYP_REASON_ERET);
 
 		/* Jump in the fire! */
 		exit_code = __guest_enter(vcpu);
 
 		/* And we're baaack! */
-		trace_hyp_enter(host_ctxt, HYP_REASON_GUEST_EXIT);
+		trace_hyp_enter(host_ctxt,
+				ARM_EXCEPTION_CODE(exit_code) == ARM_EXCEPTION_IRQ ?
+				HYP_REASON_IRQ : ESR_ELx_EC(read_sysreg_el2(SYS_ESR)));
 	} while (fixup_guest_exit(vcpu, &exit_code));
 
 	__sysreg_save_state_nvhe(guest_ctxt);
diff --git a/arch/arm64/kvm/hyp_trace.c b/arch/arm64/kvm/hyp_trace.c
index 9644c424819b..e47b91bf3ae1 100644
--- a/arch/arm64/kvm/hyp_trace.c
+++ b/arch/arm64/kvm/hyp_trace.c
@@ -400,25 +400,55 @@ static struct trace_remote_callbacks trace_remote_callbacks = {
 	.enable_event		= hyp_trace_enable_event,
 };
 
+static const char *__hyp_enter_exit_str(u8 reason, pid_t vcpu);
 static const char *__hyp_enter_exit_reason_str(u8 reason);
 
 #include <asm/kvm_define_hypevents.h>
 
+static const char *__hyp_enter_exit_str(u8 reason, pid_t vcpu)
+{
+	switch (reason) {
+	case 0 ... ESR_ELx_EC_MAX:
+	case HYP_REASON_IRQ:
+	case HYP_REASON_ERET:
+		return vcpu ? "vcpu" : "host";
+	case HYP_REASON_SMC:
+	case HYP_REASON_PSCI:
+		return "firmware";
+	default:
+		return "unknown";
+	}
+}
+
 static const char *__hyp_enter_exit_reason_str(u8 reason)
 {
-	static const char strs[][12] = {
-		"smc",
-		"hvc",
-		"sys",
-		"psci",
-		"host_abort",
-		"guest_exit",
-		"eret_host",
-		"eret_guest",
-		"unknown",
+	static const struct trace_print_flags class[] = {
+		kvm_arm_exception_class
 	};
 
-	return strs[min(reason, HYP_REASON_UNKNOWN)];
+	if (reason <= ESR_ELx_EC_MAX) {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(class); i++) {
+			if (class[i].mask == reason)
+				return class[i].name;
+		}
+
+		return "UNKNOWN_ESR";
+	}
+
+	switch (reason) {
+	case HYP_REASON_SMC:
+		return "SMC";
+	case HYP_REASON_PSCI:
+		return "PSCI";
+	case HYP_REASON_IRQ:
+		return "IRQ";
+	case HYP_REASON_ERET:
+		return "ERET";
+	default:
+		return "UNKNOWN_REASON";
+	}
 }
 
 static void __init hyp_trace_init_events(void)
-- 
2.56.0.385.gd3acb90ef8-goog