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authorChristian Borntraeger <borntraeger@de.ibm.com>2013-05-17 14:41:35 +0200
committerGleb Natapov <gleb@redhat.com>2013-05-21 11:55:23 +0300
commit49b99e1e0dedbd6cc93b2d2776b60fb7151ff3d7 (patch)
tree204052379d35e6459207571b3e2bb1d460e2cef2 /arch/s390/kernel
parent95d38fd0bcf1996082f5f8762e6f1c849755e0c6 (diff)
downloadblackbird-obmc-linux-49b99e1e0dedbd6cc93b2d2776b60fb7151ff3d7.tar.gz
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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>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/asm-offsets.c1
-rw-r--r--arch/s390/kernel/entry64.S4
2 files changed, 4 insertions, 1 deletions
diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c
index 6456bbe1fbb1..78db6338695d 100644
--- a/arch/s390/kernel/asm-offsets.c
+++ b/arch/s390/kernel/asm-offsets.c
@@ -163,6 +163,7 @@ int main(void)
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;
}
diff --git a/arch/s390/kernel/entry64.S b/arch/s390/kernel/entry64.S
index c2e81b4ea42c..c7daeefb9864 100644
--- a/arch/s390/kernel/entry64.S
+++ b/arch/s390/kernel/entry64.S
@@ -958,7 +958,9 @@ sie_loop:
lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
sie_gmap:
lg %r14,__SF_EMPTY(%r15) # get control block pointer
- oi __SIE_PROG0C+3(%r14),1 # we are in SIE now
+ oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
+ tm __SIE_PROG20+3(%r14),1 # last exit...
+ jnz sie_done
LPP __SF_EMPTY(%r15) # set guest id
sie 0(%r14)
sie_done:
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