[PATCH v3 3/3] KVM: PPC: epapr: install ev_idle hcall for e500 guest

2012-02-10 Thread Liu Yu
If the guest hypervisor node contains has-idle property.

Signed-off-by: Liu Yu yu@freescale.com
---
v3:
1. apply the hcall idle for all ppc platform
2. add a loop to prevent spurious wakeups

 arch/powerpc/kernel/Makefile |2 +-
 arch/powerpc/kernel/epapr.S  |   47 ++
 arch/powerpc/kernel/epapr_para.c |   14 ++-
 3 files changed, 61 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/kernel/epapr.S

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 1e41c76..65e24be 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -134,7 +134,7 @@ ifneq ($(CONFIG_XMON)$(CONFIG_KEXEC),)
 obj-y  += ppc_save_regs.o
 endif
 
-obj-$(CONFIG_EPAPR_PARA)   += epapr_para.o
+obj-$(CONFIG_EPAPR_PARA)   += epapr_para.o epapr.o
 obj-$(CONFIG_KVM_GUEST)+= kvm.o kvm_emul.o
 
 # Disable GCOV in odd or sensitive code
diff --git a/arch/powerpc/kernel/epapr.S b/arch/powerpc/kernel/epapr.S
new file mode 100644
index 000..34cc54f
--- /dev/null
+++ b/arch/powerpc/kernel/epapr.S
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include linux/threads.h
+#include asm/reg.h
+#include asm/page.h
+#include asm/cputable.h
+#include asm/thread_info.h
+#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:
+#ifdef CONFIG_E500
+   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 */
+#endif
+   wrteei  1
+
+idle_loop:
+   LOAD_REG_IMMEDIATE(r11, HC_VENDOR_EPAPR | HC_EV_IDLE)
+
+/* Hypercall entry point. Will be patched with device tree instructions. */
+.global epapr_hypercall_start
+epapr_hypercall_start:
+   li  r3, -1
+   nop
+   nop
+   nop
+
+   /*
+* Guard against spurious wakeups (e.g. from a hypervisor) --
+* any real interrupt will cause us to return to LR due to
+* _TLF_NAPPING.
+*/
+   b   idle_loop
diff --git a/arch/powerpc/kernel/epapr_para.c b/arch/powerpc/kernel/epapr_para.c
index 7e1561a..ff8fb78 100644
--- a/arch/powerpc/kernel/epapr_para.c
+++ b/arch/powerpc/kernel/epapr_para.c
@@ -20,6 +20,10 @@
 #include linux/of.h
 #include asm/epapr_hcalls.h
 #include asm/cacheflush.h
+#include asm/machdep.h
+
+extern void epapr_ev_idle(void);
+extern u32 epapr_hypercall_start[];
 
 u32 *epapr_hcall_insts;
 int epapr_hcall_insts_len;
@@ -28,7 +32,7 @@ static int __init epapr_para_init(void)
 {
struct device_node *hyper_node;
u32 *insts;
-   int len;
+   int len, i;
 
hyper_node = of_find_node_by_path(/hypervisor);
if (!hyper_node)
@@ -38,8 +42,16 @@ static int __init epapr_para_init(void)
if (!(len % 4)  (len = (4 * 4))) {
epapr_hcall_insts = insts;
epapr_hcall_insts_len = len;
+
+   for (i = 0; i  (len / 4); i++)
+   epapr_hypercall_start[i] = insts[i];
+   flush_icache_range((ulong)epapr_hypercall_start,
+  (ulong)epapr_hypercall_start + len);
}
 
+   if (of_get_property(hyper_node, has-idle, NULL))
+   ppc_md.power_save = epapr_ev_idle;
+
return 0;
 }
 
-- 
1.7.0.4


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Re: [PATCH v3 3/3] KVM: PPC: epapr: install ev_idle hcall for e500 guest

2012-02-10 Thread Scott Wood
On 02/10/2012 04:02 AM, Liu Yu wrote:
 +_GLOBAL(epapr_ev_idle)
 +epapr_ev_idle:
 +#ifdef CONFIG_E500
 + 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 */
 +#endif
 + wrteei  1

On what hardware would you not need to use _TLF_NAPPING?

-Scott

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