diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index 7ebacac03dc3..a1cb861154e9 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -162,13 +162,16 @@ static int pseries_smp_prepare_cpu(int cpu)
 	return 0;
 }
 
-static void smp_pseries_cause_ipi(int cpu)
+/* Cause IPI as setup by the interrupt controller (xics or xive) */
+static void (*ic_cause_ipi)(int cpu) __ro_after_init;
+
+/* Use msgsndp doorbells target is a sibling, else use interrupt controller */
+static void dbell_or_ic_cause_ipi(int cpu)
 {
-	/* POWER9 should not use this handler */
 	if (doorbell_try_core_ipi(cpu))
 		return;
 
-	icp_ops->cause_ipi(cpu);
+	ic_cause_ipi(cpu);
 }
 
 static int pseries_cause_nmi_ipi(int cpu)
@@ -192,26 +195,41 @@ static int pseries_cause_nmi_ipi(int cpu)
 	return 0;
 }
 
-static __init void pSeries_smp_probe_xics(void)
-{
-	xics_smp_probe();
-
-	if (cpu_has_feature(CPU_FTR_DBELL) && !is_secure_guest())
-		smp_ops->cause_ipi = smp_pseries_cause_ipi;
-	else
-		smp_ops->cause_ipi = icp_ops->cause_ipi;
-}
-
 static __init void pSeries_smp_probe(void)
 {
 	if (xive_enabled())
-		/*
-		 * Don't use P9 doorbells when XIVE is enabled. IPIs
-		 * using MMIOs should be faster
-		 */
 		xive_smp_probe();
 	else
-		pSeries_smp_probe_xics();
+		xics_smp_probe();
+
+	/* No doorbell facility, must use the interrupt controller for IPIs */
+	if (!cpu_has_feature(CPU_FTR_DBELL))
+		return;
+
+	/* Doorbells can only be used for IPIs between SMT siblings */
+	if (!cpu_has_feature(CPU_FTR_SMT))
+		return;
+
+	/*
+	 * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp faults
+	 * to the hypervisor which then reads the instruction from guest
+	 * memory. This can't be done if the guest is secure, so don't use
+	 * doorbells in secure guests.
+	 *
+	 * Under PowerVM, FSCR[MSGP] is enabled so doorbells could be used
+	 * by secure guests if we distinguished this from KVM.
+	 */
+	if (is_secure_guest())
+		return;
+
+	/*
+	 * The guest can use doobells for SMT sibling IPIs, which stay in
+	 * the core rather than going to the interrupt controller. This
+	 * tends to be slower under KVM where doorbells are emulated, but
+	 * faster for PowerVM where they're enabled.
+	 */
+	ic_cause_ipi = smp_ops->cause_ipi;
+	smp_ops->cause_ipi = dbell_or_ic_cause_ipi;
 }
 
 static struct smp_ops_t pseries_smp_ops = {