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, 92 insertions, 2 deletions

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 16321ad9e70c..67435b9bf98d 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -30,6 +30,7 @@
 #include <linux/ctype.h>
 
 #include <asm/ptrace.h>
+#include <asm/smp.h>
 #include <asm/string.h>
 #include <asm/prom.h>
 #include <asm/machdep.h>
@@ -48,7 +49,7 @@
 #include <asm/reg.h>
 #include <asm/debug.h>
 #include <asm/hw_breakpoint.h>
-
+#include <asm/xive.h>
 #include <asm/opal.h>
 #include <asm/firmware.h>
 
@@ -232,7 +233,13 @@ Commands:\n\
   "\
   dr	dump stream of raw bytes\n\
   dt	dump the tracing buffers (uses printk)\n\
-  e	print exception information\n\
+"
+#ifdef CONFIG_PPC_POWERNV
+"  dx#   dump xive on CPU #\n\
+  dxi#  dump xive irq state #\n\
+  dxa   dump xive on all CPUs\n"
+#endif
+"  e	print exception information\n\
   f	flush cache\n\
   la	lookup symbol+offset of specified address\n\
   ls	lookup address of specified symbol\n\
@@ -2338,6 +2345,81 @@ static void dump_pacas(void)
 }
 #endif
 
+#ifdef CONFIG_PPC_POWERNV
+static void dump_one_xive(int cpu)
+{
+	unsigned int hwid = get_hard_smp_processor_id(cpu);
+
+	opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
+	opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
+	opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
+	opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
+	opal_xive_dump(XIVE_DUMP_VP, hwid);
+	opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
+
+	if (setjmp(bus_error_jmp) != 0) {
+		catch_memory_errors = 0;
+		printf("*** Error dumping xive on cpu %d\n", cpu);
+		return;
+	}
+
+	catch_memory_errors = 1;
+	sync();
+	xmon_xive_do_dump(cpu);
+	sync();
+	__delay(200);
+	catch_memory_errors = 0;
+}
+
+static void dump_all_xives(void)
+{
+	int cpu;
+
+	if (num_possible_cpus() == 0) {
+		printf("No possible cpus, use 'dx #' to dump individual cpus\n");
+		return;
+	}
+
+	for_each_possible_cpu(cpu)
+		dump_one_xive(cpu);
+}
+
+static void dump_one_xive_irq(u32 num)
+{
+	s64 rc;
+	__be64 vp;
+	u8 prio;
+	__be32 lirq;
+
+	rc = opal_xive_get_irq_config(num, &vp, &prio, &lirq);
+	xmon_printf("IRQ 0x%x config: vp=0x%llx prio=%d lirq=0x%x (rc=%lld)\n",
+		    num, be64_to_cpu(vp), prio, be32_to_cpu(lirq), rc);
+}
+
+static void dump_xives(void)
+{
+	unsigned long num;
+	int c;
+
+	c = inchar();
+	if (c == 'a') {
+		dump_all_xives();
+		return;
+	} else if (c == 'i') {
+		if (scanhex(&num))
+			dump_one_xive_irq(num);
+		return;
+	}
+
+	termch = c;	/* Put c back, it wasn't 'a' */
+
+	if (scanhex(&num))
+		dump_one_xive(num);
+	else
+		dump_one_xive(xmon_owner);
+}
+#endif /* CONFIG_PPC_POWERNV */
+
 static void dump_by_size(unsigned long addr, long count, int size)
 {
 	unsigned char temp[16];
@@ -2386,6 +2468,14 @@ dump(void)
 		return;
 	}
 #endif
+#ifdef CONFIG_PPC_POWERNV
+	if (c == 'x') {
+		xmon_start_pagination();
+		dump_xives();
+		xmon_end_pagination();
+		return;
+	}
+#endif
 
 	if (c == '\n')
 		termch = c;