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KVM: s390: make exit_sie_sync more robust

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exit_sie_sync is used to kick CPUs out of SIE and prevent reentering at
any point in time. This is used to reload the prefix pages and to
set the IBS stuff in a way that guarantees that after this function
returns we are no longer in SIE. All current users trigger KVM requests.

The request must be set before we block the CPUs to avoid races. Let's
make this implicit by adding the request into a new function
kvm_s390_sync_requests that replaces exit_sie_sync and split out
s390_vcpu_block and s390_vcpu_unblock, that can be used to keep
CPUs out of SIE independent of requests.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
This commit is contained in:
Christian Borntraeger
2015-04-09 13:49:04 +02:00
parent 53df84f8de
commit 8e23654687
4 changed files with 22 additions and 13 deletions
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2
arch/s390/kernel/entry.S
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@@ -1005,7 +1005,7 @@ ENTRY(sie64a)
.Lsie_gmap:
lg %r14,__SF_EMPTY(%r15) # get control block pointer
oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
tm __SIE_PROG20+3(%r14),1 # last exit...
tm __SIE_PROG20+3(%r14),3 # last exit...
jnz .Lsie_done
LPP __SF_EMPTY(%r15) # set guest id
sie 0(%r14)