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s390/cpum_sf: Detect KVM guest samples

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The host-program-parameter (hpp) value of basic sample-data-entries designates
a SIE control block that is set by the LPP instruction in sie64a().
Non-zero values indicate guest samples, a value of zero indicates a host sample.

For perf samples, host and guest samples are distinguished using particular
PERF_MISC_* flags.  The perf layer calls perf_misc_flags() to set the flags
based on the pt_regs content.  For each sample-data-entry, the cpum_sf PMU
creates a pt_regs structure with the sample-data information.  An additional
flag structure is added to easily distinguish between host and guest samples.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Hendrik Brueckner
2013-12-12 17:54:57 +01:00
committed by Martin Schwidefsky
parent 443d4beb82
commit 443e802bab
3 changed files with 50 additions and 1 deletions
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25
arch/s390/kernel/perf_event.c
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@@ -1,7 +1,7 @@
/*
* Performance event support for s390x
*
* Copyright IBM Corp. 2012
* Copyright IBM Corp. 2012, 2013
* Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*
* This program is free software; you can redistribute it and/or modify
@@ -89,8 +89,31 @@ static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
: PERF_RECORD_MISC_GUEST_KERNEL;
}
static unsigned long perf_misc_flags_sf(struct pt_regs *regs)
{
struct perf_sf_sde_regs *sde_regs;
unsigned long flags;
sde_regs = (struct perf_sf_sde_regs *) &regs->int_parm_long;
if (sde_regs->in_guest)
flags = user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
: PERF_RECORD_MISC_GUEST_KERNEL;
else
flags = user_mode(regs) ? PERF_RECORD_MISC_USER
: PERF_RECORD_MISC_KERNEL;
return flags;
}
unsigned long perf_misc_flags(struct pt_regs *regs)
{
/* Check if the cpum_sf PMU has created the pt_regs structure.
* In this case, perf misc flags can be easily extracted. Otherwise,
* do regular checks on the pt_regs content.
*/
if (regs->int_code == 0x1407 && regs->int_parm == CPU_MF_INT_SF_PRA)
if (!regs->gprs[15])
return perf_misc_flags_sf(regs);
if (is_in_guest(regs))
return perf_misc_guest_flags(regs);