Merge tag 'kvm-s390-next-5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: Fix potential crash in preemptible kernels
There is a potential race for preemptible kernels, where
the host kernel would get a fault when it is preempted as
the wrong point in time.
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index cfe720d..95ef919 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -4313,16 +4313,16 @@ static void store_regs_fmt2(struct kvm_vcpu *vcpu)
kvm_run->s.regs.bpbc = (vcpu->arch.sie_block->fpf & FPF_BPBC) == FPF_BPBC;
kvm_run->s.regs.diag318 = vcpu->arch.diag318_info.val;
if (MACHINE_HAS_GS) {
+ preempt_disable();
__ctl_set_bit(2, 4);
if (vcpu->arch.gs_enabled)
save_gs_cb(current->thread.gs_cb);
- preempt_disable();
current->thread.gs_cb = vcpu->arch.host_gscb;
restore_gs_cb(vcpu->arch.host_gscb);
- preempt_enable();
if (!vcpu->arch.host_gscb)
__ctl_clear_bit(2, 4);
vcpu->arch.host_gscb = NULL;
+ preempt_enable();
}
/* SIE will save etoken directly into SDNX and therefore kvm_run */
}
