From: Martin Schwidefsky Date: Fri, 16 May 2014 08:34:11 +0000 (+0200) Subject: KVM: s390: correct locking for s390_enable_skey X-Git-Tag: omap-for-v3.17/soc-cleanup~24^2^2~5^2~11 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3a801517ad49f586f2016e1b1321e6cd28a97a04;p=pandora-kernel.git 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 Signed-off-by: Christian Borntraeger --- Reading git-diff-tree failed