s390/kvm: Provide a way to prevent reentering SIE
Lets provide functions to prevent KVM from reentering SIE and
to kick cpus out of SIE. We cannot use the common kvm_vcpu_kick code,
since we need to kick out guests in places that hold architecture
specific locks (e.g. pgste lock) which might be necessary on the
other cpus - so no waiting possible.
So lets provide a bit in a private field of the sie control block
that acts as a gate keeper, after we claimed we are in SIE.
Please note that we do not reuse prog0c, since we want to access
that bit without atomic ops.
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 6456bbe..78db633 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -163,6 +163,7 @@
DEFINE(__THREAD_trap_tdb, offsetof(struct task_struct, thread.trap_tdb));
DEFINE(__GMAP_ASCE, offsetof(struct gmap, asce));
DEFINE(__SIE_PROG0C, offsetof(struct kvm_s390_sie_block, prog0c));
+ DEFINE(__SIE_PROG20, offsetof(struct kvm_s390_sie_block, prog20));
#endif /* CONFIG_32BIT */
return 0;
}
