[PATCH v7 12/14] KVM: s390: Fix ordering when adding to SCA
Claudio Imbrenda <[email protected]>
| Newsgroups | org.kernel.vger.linux-s390,org.kernel.vger.kvm,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
When adding a new vCPU to the SCA area, the validity bit in the MCN was
set before the pointer to the state description, potentially allowing
for a race.
Fix by setting the pointer before setting the bit.
Fixes: 14542a0a54c5 ("KVM: S390: Remove sca_lock")
Signed-off-by: Claudio Imbrenda <[email protected]>
Reviewed-by: Steffen Eiden <[email protected]>
Reviewed-by: Janosch Frank <[email protected]>
---
arch/s390/kvm/kvm-s390.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 9b8a35e7dc82..518a69c55e85 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3485,8 +3485,8 @@ static void sca_add_vcpu(struct kvm_vcpu *vcpu)
if (!kvm_s390_use_sca_entries())
return;
+ WRITE_ONCE(sca->cpu[vcpu->vcpu_id].sda, virt_to_phys(vcpu->arch.sie_block));
set_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn);
- sca->cpu[vcpu->vcpu_id].sda = virt_to_phys(vcpu->arch.sie_block);
}
static int sca_can_add_vcpu(struct kvm *kvm, unsigned int id)
--
2.55.0