s390/cpumf: Use configuration level indication for sampling data

Newer hardware provides the level of virtualization that a particular
sample belongs to. Use that information and fall back to the old
heuristics if the sample does not contain that information.

Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 22 insertions, 8 deletions

diff --git a/arch/s390/include/asm/cpu_mf.h b/arch/s390/include/asm/cpu_mf.h
index 03516476127b..b69d8bc231a5 100644
--- a/arch/s390/include/asm/cpu_mf.h
+++ b/arch/s390/include/asm/cpu_mf.h
@@ -104,7 +104,8 @@ struct hws_basic_entry {
         unsigned int P:1;           /* 28 PSW Problem state              */
         unsigned int AS:2;          /* 29-30 PSW address-space control   */
         unsigned int I:1;           /* 31 entry valid or invalid         */
-        unsigned int:16;
+        unsigned int CL:2;          /* 32-33 Configuration Level         */
+        unsigned int:14;
         unsigned int prim_asn:16;   /* primary ASN                       */
         unsigned long long ia;      /* Instruction Address               */
         unsigned long long gpp;     /* Guest Program Parameter           */
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c
index 4e7ee8647b8b..763dec18edcd 100644
--- a/arch/s390/kernel/perf_cpum_sf.c
+++ b/arch/s390/kernel/perf_cpum_sf.c
@@ -1002,16 +1002,29 @@ static int perf_push_sample(struct perf_event *event, struct sf_raw_sample *sfr)
         psw_bits(regs.psw).as = sfr->basic.AS;
 
         /*
-         * A non-zero guest program parameter indicates a guest
-         * sample.
-         * Note that some early samples or samples from guests without
+         * Use the hardware provided configuration level to decide if the
+         * sample belongs to a guest or host. If that is not available,
+         * fall back to the following heuristics:
+         * A non-zero guest program parameter always indicates a guest
+         * sample. Some early samples or samples from guests without
          * lpp usage would be misaccounted to the host. We use the asn
-         * value as a heuristic to detect most of these guest samples.
-         * If the value differs from the host hpp value, we assume
-         * it to be a KVM guest.
+         * value as an addon heuristic to detect most of these guest samples.
+         * If the value differs from the host hpp value, we assume to be a
+         * KVM guest.
          */
-        if (sfr->basic.gpp || sfr->basic.prim_asn != (u16) sfr->basic.hpp)
+        switch (sfr->basic.CL) {
+        case 1: /* logical partition */
+                sde_regs->in_guest = 0;
+                break;
+        case 2: /* virtual machine */
                 sde_regs->in_guest = 1;
+                break;
+        default: /* old machine, use heuristics */
+                if (sfr->basic.gpp ||
+                    sfr->basic.prim_asn != (u16)sfr->basic.hpp)
+                        sde_regs->in_guest = 1;
+                break;
+        }
 
         overflow = 0;
         if (perf_exclude_event(event, &regs, sde_regs))