powerpc/xive: Native exploitation of the XIVE interrupt controller

The XIVE interrupt controller is the new interrupt controller
found in POWER9. It supports advanced virtualization capabilities
among other things.

Currently we use a set of firmware calls that simulate the old
"XICS" interrupt controller but this is fairly inefficient.

This adds the framework for using XIVE along with a native
backend which OPAL for configuration. Later, a backend allowing
the use in a KVM or PowerVM guest will also be provided.

This disables some fast path for interrupts in KVM when XIVE is
enabled as these rely on the firmware emulation code which is no
longer available when the XIVE is used natively by Linux.

A latter patch will make KVM also directly exploit the XIVE, thus
recovering the lost performance (and more).

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Fixup pr_xxx("XIVE:"...), don't split pr_xxx() strings,
 tweak Kconfig so XIVE_NATIVE selects XIVE and depends on POWERNV,
 fix build errors when SMP=n, fold in fixes from Ben:
   Don't call cpu_online() on an invalid CPU number
   Fix irq target selection returning out of bounds cpu#
   Extra sanity checks on cpu numbers
 ]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 32 insertions, 7 deletions

diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c
index 8b67e1eefb5c..f57195588c6c 100644
--- a/arch/powerpc/platforms/powernv/smp.c
+++ b/arch/powerpc/platforms/powernv/smp.c
@@ -29,6 +29,7 @@
 #include <asm/vdso_datapage.h>
 #include <asm/cputhreads.h>
 #include <asm/xics.h>
+#include <asm/xive.h>
 #include <asm/opal.h>
 #include <asm/runlatch.h>
 #include <asm/code-patching.h>
@@ -47,7 +48,9 @@
 
 static void pnv_smp_setup_cpu(int cpu)
 {
-	if (cpu != boot_cpuid)
+	if (xive_enabled())
+		xive_smp_setup_cpu();
+	else if (cpu != boot_cpuid)
 		xics_setup_cpu();
 
 #ifdef CONFIG_PPC_DOORBELL
@@ -132,7 +135,10 @@ static int pnv_smp_cpu_disable(void)
 	vdso_data->processorCount--;
 	if (cpu == boot_cpuid)
 		boot_cpuid = cpumask_any(cpu_online_mask);
-	xics_migrate_irqs_away();
+	if (xive_enabled())
+		xive_smp_disable_cpu();
+	else
+		xics_migrate_irqs_away();
 	return 0;
 }
 
@@ -213,9 +219,12 @@ static void pnv_smp_cpu_kill_self(void)
 		if (((srr1 & wmask) == SRR1_WAKEEE) ||
 		    ((srr1 & wmask) == SRR1_WAKEHVI) ||
 		    (local_paca->irq_happened & PACA_IRQ_EE)) {
-			if (cpu_has_feature(CPU_FTR_ARCH_300))
-				icp_opal_flush_interrupt();
-			else
+			if (cpu_has_feature(CPU_FTR_ARCH_300)) {
+				if (xive_enabled())
+					xive_flush_interrupt();
+				else
+					icp_opal_flush_interrupt();
+			} else
 				icp_native_flush_interrupt();
 		} else if ((srr1 & wmask) == SRR1_WAKEHDBELL) {
 			unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
@@ -252,10 +261,26 @@ static int pnv_cpu_bootable(unsigned int nr)
 	return smp_generic_cpu_bootable(nr);
 }
 
+static int pnv_smp_prepare_cpu(int cpu)
+{
+	if (xive_enabled())
+		return xive_smp_prepare_cpu(cpu);
+	return 0;
+}
+
+static void __init pnv_smp_probe(void)
+{
+	if (xive_enabled())
+		xive_smp_probe();
+	else
+		xics_smp_probe();
+}
+
 static struct smp_ops_t pnv_smp_ops = {
 	.message_pass	= smp_muxed_ipi_message_pass,
-	.cause_ipi	= NULL,	/* Filled at runtime by xics_smp_probe() */
-	.probe		= xics_smp_probe,
+	.cause_ipi	= NULL, /* Filled at runtime by xi{cs,ve}_smp_probe() */
+	.probe		= pnv_smp_probe,
+	.prepare_cpu	= pnv_smp_prepare_cpu,
 	.kick_cpu	= pnv_smp_kick_cpu,
 	.setup_cpu	= pnv_smp_setup_cpu,
 	.cpu_bootable	= pnv_cpu_bootable,