Patchwork [v10,4/5] KVM: PPC: ev_idle hcall support for e500 guests

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Submitter Stuart Yoder
Date March 15, 2012, 8:52 p.m.
Message ID <1331844737-30869-5-git-send-email-stuart.yoder@freescale.com>
Download mbox | patch
Permalink /patch/147074/
State New
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Comments

Stuart Yoder - March 15, 2012, 8:52 p.m.
From: Liu Yu-B13201 <Yu.Liu@freescale.com>

Signed-off-by: Liu Yu <yu.liu@freescale.com>
[stuart: update patch description]
Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
---
v10:
   -add spaces as per comments
   -use PPC_LL/PPC_STL for long accesses

 arch/powerpc/include/asm/epapr_hcalls.h |   11 ++++++-----
 arch/powerpc/kernel/epapr_hcalls.S      |   28 ++++++++++++++++++++++++++++
 arch/powerpc/kernel/epapr_paravirt.c    |   11 ++++++++++-
 3 files changed, 44 insertions(+), 6 deletions(-)
Alexander Graf - May 8, 2012, 10:45 a.m.
On 15.03.2012, at 21:52, Stuart Yoder wrote:

> From: Liu Yu-B13201 <Yu.Liu@freescale.com>
> 
> Signed-off-by: Liu Yu <yu.liu@freescale.com>
> [stuart: update patch description]
> Signed-off-by: Stuart Yoder <stuart.yoder@freescale.com>
> ---
> v10:
>   -add spaces as per comments
>   -use PPC_LL/PPC_STL for long accesses
> 
> arch/powerpc/include/asm/epapr_hcalls.h |   11 ++++++-----
> arch/powerpc/kernel/epapr_hcalls.S      |   28 ++++++++++++++++++++++++++++
> arch/powerpc/kernel/epapr_paravirt.c    |   11 ++++++++++-
> 3 files changed, 44 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
> index 2173d4c..78460ac 100644
> --- a/arch/powerpc/include/asm/epapr_hcalls.h
> +++ b/arch/powerpc/include/asm/epapr_hcalls.h
> @@ -50,10 +50,6 @@
> #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
> @@ -108,6 +104,11 @@
> #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
>  *
> @@ -500,5 +501,5 @@ static inline unsigned int ev_idle(void)
> 
> 	return r3;
> }
> -
> +#endif /* !__ASSEMBLY__ */
> #endif
> diff --git a/arch/powerpc/kernel/epapr_hcalls.S b/arch/powerpc/kernel/epapr_hcalls.S
> index 697b390..698e7d9 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>
> 
> +_GLOBAL(epapr_ev_idle)
> +epapr_ev_idle:

Please document here that this is a copy from the original idle code.

> +	rlwinm	r3, r1, 0, 0, 31-THREAD_SHIFT	/* current thread_info */
> +	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))

Ah, nice. So why not use EV_HCALL_TOKEN instead of the clumsy _EV_HCALL_TOKEN(EV_EPAPR_VENDOR_ID, EV_IDLE)? We could also add a KVM_HCALL_TOKEN() similar to the fsl one:

  arch/powerpc/include/asm/fsl_hcalls.h:#define FH_HCALL_TOKEN(num)		_EV_HCALL_TOKEN(EV_FSL_VENDOR_ID, num)

which would help us keep our lines short :).


Alex

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Patch

diff --git a/arch/powerpc/include/asm/epapr_hcalls.h b/arch/powerpc/include/asm/epapr_hcalls.h
index 2173d4c..78460ac 100644
--- a/arch/powerpc/include/asm/epapr_hcalls.h
+++ b/arch/powerpc/include/asm/epapr_hcalls.h
@@ -50,10 +50,6 @@ 
 #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
@@ -108,6 +104,11 @@ 
 #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
  *
@@ -500,5 +501,5 @@  static inline unsigned int ev_idle(void)
 
 	return r3;
 }
-
+#endif /* !__ASSEMBLY__ */
 #endif
diff --git a/arch/powerpc/kernel/epapr_hcalls.S b/arch/powerpc/kernel/epapr_hcalls.S
index 697b390..698e7d9 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>
 
+_GLOBAL(epapr_ev_idle)
+epapr_ev_idle:
+	rlwinm	r3, r1, 0, 0, 31-THREAD_SHIFT	/* current thread_info */
+	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 028aeae..f3eab85 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;