[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>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 2d92c2cf92d7..c00856ad4e5a 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -356,6 +356,7 @@ static __init void detect_machine_facilities(void)
 {
 #ifdef CONFIG_64BIT
         unsigned int facilities;
+        unsigned long long facility_bits;
 
         facilities = stfl();
         if (facilities & (1 << 28))
@@ -364,6 +365,9 @@ static __init void detect_machine_facilities(void)
                 S390_lowcore.machine_flags |= MACHINE_FLAG_PFMF;
         if (facilities & (1 << 4))
                 S390_lowcore.machine_flags |= MACHINE_FLAG_MVCOS;
+        if ((stfle(&facility_bits, 1) > 0) &&
+            (facility_bits & (1ULL << (63 - 40))))
+                S390_lowcore.machine_flags |= MACHINE_FLAG_SPP;
 #endif
 }