git.stricted.de - GitHub/moto-9609/android_kernel_motorola

author	Martin Schwidefsky <schwidefsky@de.ibm.com>
	Fri, 16 May 2014 08:34:11 +0000 (10:34 +0200)
committer	Christian Borntraeger <borntraeger@de.ibm.com>
	Fri, 16 May 2014 12:57:17 +0000 (14:57 +0200)
commit	3a801517ad49f586f2016e1b1321e6cd28a97a04
tree	b1d3a84ccbeb491202dd2b402463a0d9e454408f	tree \| snapshot (tar.gz zip)
parent	d9f89b88f5102ce235b75a5907838e3c7ed84b97	commit \| diff

KVM: s390: correct locking for s390_enable_skey

Use the mm semaphore to serialize multiple invocations of s390_enable_skey.
The second CPU faulting on a storage key operation needs to wait for the
completion of the page table update. Taking the mm semaphore writable
has the positive side-effect that it prevents any host faults from
taking place which does have implications on keys vs PGSTE.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>