KVM: PPC: ev_idle hcall support for e500 guests

Signed-off-by: Liu Yu <[e-mail]>
[varun: 64-bit changes]
Signed-off-by: Varun Sethi <[e-mail]>
Signed-off-by: Stuart Yoder <[e-mail]>
Signed-off-by: Alexander Graf <[e-mail]>

arch/powerpc/include/asm/epapr_hcalls.h

···
 #ifndef _EPAPR_HCALLS_H
 #define _EPAPR_HCALLS_H
 
-#include <linux/types.h>
-#include <linux/errno.h>
-#include <asm/byteorder.h>
-
 #define EV_BYTE_CHANNEL_SEND		1
 #define EV_BYTE_CHANNEL_RECEIVE		2
 #define EV_BYTE_CHANNEL_POLL		3
···
 #define EV_INVALID_STATE	11	/* The object is in an invalid state */
 #define EV_UNIMPLEMENTED	12	/* Unimplemented hypercall */
 #define EV_BUFFER_OVERFLOW	13	/* Caller-supplied buffer too small */
+
+#ifndef __ASSEMBLY__
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <asm/byteorder.h>
 
 /*
  * Hypercall register clobber list
···
 
 	return r3;
 }
-
+#endif /* !__ASSEMBLY__ */
 #endif

arch/powerpc/kernel/epapr_hcalls.S

···
  */
 
 #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

arch/powerpc/kernel/epapr_paravirt.c

···
 #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;
 
···
 	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;