KVM: PPC: ev_idle hcall support for e500 guests

Signed-off-by: Liu Yu <yu.liu@freescale.com>
[varun: 64-bit changes]
Signed-off-by: Varun Sethi <Varun.Sethi@freescale.com>
Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

2 files changed, 38 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/epapr_hcalls.S b/arch/powerpc/kernel/epapr_hcalls.S
index 697b390ebfd8..62c0dc237826 100644
--- a/arch/powerpc/kernel/epapr_hcalls.S
+++ b/arch/powerpc/kernel/epapr_hcalls.S
@@ -8,13 +8,41 @@
  */
 
 #include <linux/threads.h>
+#include <asm/epapr_hcalls.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-compat.h>
 #include <asm/asm-offsets.h>
 
+/* epapr_ev_idle() was derived from e500_idle() */
+_GLOBAL(epapr_ev_idle)
+        CURRENT_THREAD_INFO(r3, r1)
+        PPC_LL  r4, TI_LOCAL_FLAGS(r3)  /* set napping bit */
+        ori     r4, r4,_TLF_NAPPING     /* so when we take an exception */
+        PPC_STL r4, TI_LOCAL_FLAGS(r3)  /* it will return to our caller */
+
+        wrteei  1
+
+idle_loop:
+        LOAD_REG_IMMEDIATE(r11, EV_HCALL_TOKEN(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 028aeae370b6..f3eab8594d9f 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_paravirt_enabled;
 
@@ -41,8 +45,13 @@ static int __init epapr_paravirt_init(void)
         if (len % 4 || len > (4 * 4))
                 return -ENODEV;
 
-        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_paravirt_enabled = true;