Re: [PATCH] KVM: s390: fix guarded storage control register handling

Christian Borntraeger
2021-04-15T10:50:20Z

On 15.04.21 10:01, Heiko Carstens wrote:
> store_regs_fmt2() has an ordering problem: first the guarded storage
> facility is enabled on the local cpu, then preemption disabled, and
> then the STGSC (store guarded storage controls) instruction is
> executed.
>
> If the process gets scheduled away between enabling the guarded
> storage facility and before preemption is disabled, this might lead to
> a special operation exception and therefore kernel crash as soon as
> the process is scheduled back and the STGSC instruction is executed.
>
> Fixes: 4e0b1ab72b8a ("KVM: s390: gs support for kvm guests")
> Cc: <stable@vger.kernel.org> # 4.12
> Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Thanks applied. Will queue for the s390kvm tree after the CI/regression has finished.