[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 a7251580891c..2f4b687cc7fa 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 934fd6a885f6..31646bd0e469 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"