[S390] virtualization aware cpu measurement

Use the SPP instruction to set a tag on entry to / exit of the virtual
machine context. This allows the cpu measurement facility to distinguish
the samples from the host and the different guests.

Signed-off-by: Carsten Otte <cotte@de.ibm.com>

2 files changed, 75 insertions, 13 deletions

diff --git a/arch/s390/kvm/Kconfig b/arch/s390/kvm/Kconfig
index a7251580891..2f4b687cc7f 100644
--- a/arch/s390/kvm/Kconfig
+++ b/arch/s390/kvm/Kconfig
@@ -33,6 +33,17 @@ config KVM
 
 	  If unsure, say N.
 
+config KVM_AWARE_CMF
+	depends on KVM
+	bool "KVM aware sampling"
+	---help---
+	  This option enhances the sampling data from the CPU Measurement
+	  Facility with additional information, that allows to distinguish
+	  guest(s) and host when using the kernel based virtual machine
+	  functionality.
+
+	  If unsure, say N.
+
 # OK, it's a little counter-intuitive to do this, but it puts it neatly under
 # the virtualization menu.
 source drivers/vhost/Kconfig
diff --git a/arch/s390/kvm/sie64a.S b/arch/s390/kvm/sie64a.S
index 934fd6a885f..31646bd0e46 100644
--- a/arch/s390/kvm/sie64a.S
+++ b/arch/s390/kvm/sie64a.S
@@ -1,20 +1,60 @@
 /*
  * sie64a.S - low level sie call
  *
- * Copyright IBM Corp. 2008
+ * Copyright IBM Corp. 2008,2010
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License (version 2 only)
  * as published by the Free Software Foundation.
  *
  *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ *		 Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
  */
 
 #include <linux/errno.h>
 #include <asm/asm-offsets.h>
+#include <asm/setup.h>
+#include <asm/asm-offsets.h>
+#include <asm/ptrace.h>
+#include <asm/thread_info.h>
+
+_TIF_EXIT_SIE = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)
+
+/*
+ * offsets into stackframe
+ * SP_	= offsets into stack sie64 is called with
+ * SPI_ = offsets into irq stack
+ */
+SP_GREGS = __SF_EMPTY
+SP_HOOK  = __SF_EMPTY+8
+SP_GPP	 = __SF_EMPTY+16
+SPI_PSW  = STACK_FRAME_OVERHEAD + __PT_PSW
+
 
-SP_R5 =	5 * 8	# offset into stackframe
-SP_R6 =	6 * 8
+	.macro SPP newpp
+#ifdef CONFIG_KVM_AWARE_CMF
+	tm	__LC_MACHINE_FLAGS+6,0x20	# MACHINE_FLAG_SPP
+	jz	0f
+	.insn	s,0xb2800000,\newpp
+	0:
+#endif
+	.endm
+
+sie_irq_handler:
+	SPP	__LC_CMF_HPP			# set host id
+	larl	%r2,sie_inst
+	clg	%r2,SPI_PSW+8(0,%r15)		# intercepted sie
+	jne	1f
+	xc	__LC_SIE_HOOK(8),__LC_SIE_HOOK
+	lg	%r2,__LC_THREAD_INFO		# pointer thread_info struct
+	tm	__TI_flags+7(%r2),_TIF_EXIT_SIE
+	jz	0f
+	larl	%r2,sie_exit			# work pending, leave sie
+	stg	%r2,__LC_RETURN_PSW+8
+	br	%r14
+0:	larl	%r2,sie_reenter			# re-enter with guest id
+	stg	%r2,__LC_RETURN_PSW+8
+1:	br	%r14
 
 /*
  * sie64a calling convention:
@@ -23,23 +63,34 @@ SP_R6 =	6 * 8
  */
 	.globl	sie64a
 sie64a:
-	lgr	%r5,%r3
-	stmg	%r5,%r14,SP_R5(%r15)	# save register on entry
-	lgr	%r14,%r2		# pointer to sie control block
-	lmg	%r0,%r13,0(%r3)		# load guest gprs 0-13
+	stg	%r3,SP_GREGS(%r15)		# save guest register save area
+	stmg	%r6,%r14,__SF_GPRS(%r15)	# save registers on entry
+	lgr	%r14,%r2			# pointer to sie control block
+	larl	%r5,sie_irq_handler
+	stg	%r2,SP_GPP(%r15)
+	stg	%r5,SP_HOOK(%r15)		# save hook target
+	lmg	%r0,%r13,0(%r3)			# load guest gprs 0-13
+sie_reenter:
+	mvc	__LC_SIE_HOOK(8),SP_HOOK(%r15)
+	SPP	SP_GPP(%r15)			# set guest id
 sie_inst:
 	sie	0(%r14)
-	lg	%r14,SP_R5(%r15)
-	stmg	%r0,%r13,0(%r14)	# save guest gprs 0-13
+	xc	__LC_SIE_HOOK(8),__LC_SIE_HOOK
+	SPP	__LC_CMF_HPP			# set host id
+sie_exit:
+	lg	%r14,SP_GREGS(%r15)
+	stmg	%r0,%r13,0(%r14)		# save guest gprs 0-13
 	lghi	%r2,0
-	lmg	%r6,%r14,SP_R6(%r15)
+	lmg	%r6,%r14,__SF_GPRS(%r15)
 	br	%r14
 
 sie_err:
-	lg	%r14,SP_R5(%r15)
-	stmg	%r0,%r13,0(%r14)	# save guest gprs 0-13
+	xc	__LC_SIE_HOOK(8),__LC_SIE_HOOK
+	SPP	__LC_CMF_HPP			# set host id
+	lg	%r14,SP_GREGS(%r15)
+	stmg	%r0,%r13,0(%r14)		# save guest gprs 0-13
 	lghi	%r2,-EFAULT
-	lmg	%r6,%r14,SP_R6(%r15)
+	lmg	%r6,%r14,__SF_GPRS(%r15)
 	br	%r14
 
 	.section __ex_table,"a"