[PATCH v8 04/13] KVM: s390: Fix overclearing ESCA in case of error

[Claudio Imbrenda]

If an attempt is made to create a vCPU with an already existing ID,
the duplicated vCPU will be destroyed. When destroying a vCPU, its
ESCA entry will be cleared. In the above scenario, the spurious
duplicate vCPU is destroyed, but the ESCA entry corresponding to the
original vCPU is cleared.

Fix by skipping clearing the ESCA entry if the vCPU creation was not
successful, i.e. if the vcpu->arch.initialized is still zero.

Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
Reviewed-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
 arch/s390/kvm/interrupt.c | 2 +-
 arch/s390/kvm/kvm-s390.c  | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
index 9e3e6b0d72ad..2acdff130fa6 100644
--- a/arch/s390/kvm/interrupt.c
+++ b/arch/s390/kvm/interrupt.c
@@ -86,7 +86,7 @@ static void sca_clear_ext_call(struct kvm_vcpu *vcpu)
 	struct esca_block *sca = vcpu->kvm->arch.sca;
 	union esca_sigp_ctrl *sigp_ctrl = &sca->cpu[vcpu->vcpu_id].sigp_ctrl;
 
-	if (!kvm_s390_use_sca_entries())
+	if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized)
 		return;
 	kvm_s390_clear_cpuflags(vcpu, CPUSTAT_ECALL_PEND);
 
diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 9be27db0a21e..5b2727d7dfd1 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3462,7 +3462,7 @@ static void sca_del_vcpu(struct kvm_vcpu *vcpu)
 {
 	struct esca_block *sca = vcpu->kvm->arch.sca;
 
-	if (!kvm_s390_use_sca_entries())
+	if (!kvm_s390_use_sca_entries() || !vcpu->arch.initialized)
 		return;
 
 	clear_bit_inv(vcpu->vcpu_id, (unsigned long *)sca->mcn);
-- 
2.55.0