KVM: PPC: Book3S HV: Add ICP real mode counters

Add two counters to count how often we generate real-mode ICS resend
and reject events. The counters provide some performance statistics
that could be used in the future to consider if the real mode functions
need further optimizing. The counters are displayed as part of IPC and
ICP state provided by /sys/debug/kernel/powerpc/kvm* for each VM.

Also added two counters that count (approximately) how many times we
don't find an ICP or ICS we're looking for. These are not currently
exposed through sysfs, but can be useful when debugging crashes.

Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>

arch/powerpc/kvm/book3s_hv_rm_xics.c

@@ -227,6 +227,7 @@ static void icp_rm_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
 	ics = kvmppc_xics_find_ics(xics, new_irq, &src);
 	if (!ics) {
 		/* Unsafe increment, but this does not need to be accurate */
+		xics->err_noics++;
 		return;
 	}
 	state = &ics->irq_state[src];
@@ -239,6 +240,7 @@ static void icp_rm_deliver_irq(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
 		icp = kvmppc_xics_find_server(xics->kvm, state->server);
 		if (!icp) {
 			/* Unsafe increment again*/
+			xics->err_noicp++;
 			goto out;
 		}
 	}
@@ -383,6 +385,7 @@ static void icp_rm_down_cppr(struct kvmppc_xics *xics, struct kvmppc_icp *icp,
 	 * separately here as well.
 	 */
 	if (resend) {
+		icp->n_check_resend++;
 		icp_rm_check_resend(xics, icp);
 	}
 }
@@ -500,11 +503,13 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
 
 	/* Handle reject in real mode */
 	if (reject && reject != XICS_IPI) {
+		this_icp->n_reject++;
 		icp_rm_deliver_irq(xics, icp, reject);
 	}
 
 	/* Handle resends in real mode */
 	if (resend) {
+		this_icp->n_check_resend++;
 		icp_rm_check_resend(xics, icp);
 	}
 
@@ -566,6 +571,7 @@ int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
 	 * attempt (see comments in icp_rm_deliver_irq).
 	 */
 	if (reject && reject != XICS_IPI) {
+		icp->n_reject++;
 		icp_rm_deliver_irq(xics, icp, reject);
 	}
  bail:
@@ -616,6 +622,7 @@ int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
 
 	/* Still asserted, resend it */
 	if (state->asserted) {
+		icp->n_reject++;
 		icp_rm_deliver_irq(xics, icp, irq);
 	}
 

arch/powerpc/kvm/book3s_xics.c

@@ -901,6 +901,7 @@ static int xics_debug_show(struct seq_file *m, void *private)
 	unsigned long flags;
 	unsigned long t_rm_kick_vcpu, t_rm_check_resend;
 	unsigned long t_rm_reject, t_rm_notify_eoi;
+	unsigned long t_reject, t_check_resend;
 
 	if (!kvm)
 		return 0;
@@ -909,6 +910,8 @@ static int xics_debug_show(struct seq_file *m, void *private)
 	t_rm_notify_eoi = 0;
 	t_rm_check_resend = 0;
 	t_rm_reject = 0;
+	t_check_resend = 0;
+	t_reject = 0;
 
 	seq_printf(m, "=========\nICP state\n=========\n");
 
@@ -928,12 +931,15 @@ static int xics_debug_show(struct seq_file *m, void *private)
 		t_rm_notify_eoi += icp->n_rm_notify_eoi;
 		t_rm_check_resend += icp->n_rm_check_resend;
 		t_rm_reject += icp->n_rm_reject;
+		t_check_resend += icp->n_check_resend;
+		t_reject += icp->n_reject;
 	}
 
-	seq_puts(m, "ICP Guest Real Mode exit totals: ");
-	seq_printf(m, "\tkick_vcpu=%lu check_resend=%lu reject=%lu notify_eoi=%lu\n",
+	seq_printf(m, "ICP Guest->Host totals: kick_vcpu=%lu check_resend=%lu reject=%lu notify_eoi=%lu\n",
 			t_rm_kick_vcpu, t_rm_check_resend,
 			t_rm_reject, t_rm_notify_eoi);
+	seq_printf(m, "ICP Real Mode totals: check_resend=%lu resend=%lu\n",
+			t_check_resend, t_reject);
 	for (icsid = 0; icsid <= KVMPPC_XICS_MAX_ICS_ID; icsid++) {
 		struct kvmppc_ics *ics = xics->ics[icsid];
 

arch/powerpc/kvm/book3s_xics.h

@@ -83,6 +83,9 @@ struct kvmppc_icp {
 	unsigned long n_rm_check_resend;
 	unsigned long n_rm_reject;
 	unsigned long n_rm_notify_eoi;
+	/* Counters for handling ICP processing in real mode */
+	unsigned long n_check_resend;
+	unsigned long n_reject;
 
 	/* Debug stuff for real mode */
 	union kvmppc_icp_state rm_dbgstate;
@@ -102,6 +105,8 @@ struct kvmppc_xics {
 	u32 max_icsid;
 	bool real_mode;
 	bool real_mode_dbg;
+	u32 err_noics;
+	u32 err_noicp;
 	struct kvmppc_ics *ics[KVMPPC_XICS_MAX_ICS_ID + 1];
 };