[PATCH v5 3/4] KVM: PPC: epapr: install ev_idle hcall for e500 guest

[Liu Yu]

If the guest hypervisor node contains "has-idle" property.

Signed-off-by: Liu Yu <yu.liu at freescale.com>
---
v5: no change

 arch/powerpc/kernel/epapr_hcalls.S   |   29 +++++++++++++++++++++++++++++
 arch/powerpc/kernel/epapr_paravirt.c |   11 ++++++++++-
 2 files changed, 39 insertions(+), 1 deletions(-)

diff --git a/arch/powerpc/kernel/epapr_hcalls.S b/arch/powerpc/kernel/epapr_hcalls.S
index 697b390..72fa234 100644
--- a/arch/powerpc/kernel/epapr_hcalls.S
+++ b/arch/powerpc/kernel/epapr_hcalls.S
@@ -15,6 +15,35 @@
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 
+#define HC_VENDOR_EPAPR		(1 << 16)
+#define HC_EV_IDLE		16
+
+_GLOBAL(epapr_ev_idle)
+epapr_ev_idle:
+	rlwinm	r3,r1,0,0,31-THREAD_SHIFT	/* current thread_info */
+	lwz	r4,TI_LOCAL_FLAGS(r3)	/* set napping bit */
+	ori	r4,r4,_TLF_NAPPING	/* so when we take an exception */
+	stw	r4,TI_LOCAL_FLAGS(r3)	/* it will return to our caller */
+
+	wrteei	1
+
+idle_loop:
+	LOAD_REG_IMMEDIATE(r11, HC_VENDOR_EPAPR | HC_EV_IDLE)
+
+.global epapr_ev_idle_start
+epapr_ev_idle_start:
+	li	r3, -1
+	nop
+	nop
+	nop
+
+	/*
+	 * Guard against spurious wakeups from a hypervisor --
+	 * only interrupt will cause us to return to LR due to
+	 * _TLF_NAPPING.
+	 */
+	b	idle_loop
+
 /* Hypercall entry point. Will be patched with device tree instructions. */
 .global epapr_hypercall_start
 epapr_hypercall_start:
diff --git a/arch/powerpc/kernel/epapr_paravirt.c b/arch/powerpc/kernel/epapr_paravirt.c
index e601da7..43d875e 100644
--- a/arch/powerpc/kernel/epapr_paravirt.c
+++ b/arch/powerpc/kernel/epapr_paravirt.c
@@ -21,6 +21,10 @@
 #include <asm/epapr_hcalls.h>
 #include <asm/cacheflush.h>
 #include <asm/code-patching.h>
+#include <asm/machdep.h>
+
+extern void epapr_ev_idle(void);
+extern u32 epapr_ev_idle_start[];
 
 bool epapr_para_enabled = false;
 
@@ -39,8 +43,13 @@ static int __init epapr_para_init(void)
 
 	insts = of_get_property(hyper_node, "hcall-instructions", &len);
 	if (insts && !(len % 4) && len <= (4 * 4)) {
-		for (i = 0; i < (len / 4); i++)
+		for (i = 0; i < (len / 4); i++) {
 			patch_instruction(epapr_hypercall_start + i, insts[i]);
+			patch_instruction(epapr_ev_idle_start + i, insts[i]);
+		}
+
+		if (of_get_property(hyper_node, "has-idle", NULL))
+			ppc_md.power_save = epapr_ev_idle;
 
 		epapr_para_enabled = true;
 	} else {
-- 
1.7.0.4