From: Halil Pasic pasic@linux.ibm.com
commit a3e03bc1368c1bc16e19b001fc96dc7430573cc8 upstream.
While in practice vcpu->vcpu_idx == vcpu->vcp_id is often true, it may not always be, and we must not rely on this. Reason is that KVM decides the vcpu_idx, userspace decides the vcpu_id, thus the two might not match.
Currently kvm->arch.idle_mask is indexed by vcpu_id, which implies that code like for_each_set_bit(vcpu_id, kvm->arch.idle_mask, online_vcpus) { vcpu = kvm_get_vcpu(kvm, vcpu_id); do_stuff(vcpu); } is not legit. Reason is that kvm_get_vcpu expects an vcpu_idx, not an vcpu_id. The trouble is, we do actually use kvm->arch.idle_mask like this. To fix this problem we have two options. Either use kvm_get_vcpu_by_id(vcpu_id), which would loop to find the right vcpu_id, or switch to indexing via vcpu_idx. The latter is preferable for obvious reasons.
Let us make switch from indexing kvm->arch.idle_mask by vcpu_id to indexing it by vcpu_idx. To keep gisa_int.kicked_mask indexed by the same index as idle_mask lets make the same change for it as well.
Fixes: 1ee0bc559dc3 ("KVM: s390: get rid of local_int array") Signed-off-by: Halil Pasic pasic@linux.ibm.com Reviewed-by: Christian Bornträger borntraeger@de.ibm.com Reviewed-by: Claudio Imbrenda imbrenda@linux.ibm.com Cc: stable@vger.kernel.org # 3.15+ Link: https://lore.kernel.org/r/20210827125429.1912577-1-pasic@linux.ibm.com [borntraeger@de.ibm.com]: change idle mask, remove kicked_mask Signed-off-by: Christian Borntraeger borntraeger@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kvm/interrupt.c | 4 ++-- arch/s390/kvm/kvm-s390.h | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
--- a/arch/s390/kvm/interrupt.c +++ b/arch/s390/kvm/interrupt.c @@ -318,13 +318,13 @@ static unsigned long deliverable_irqs(st static void __set_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_set_cpuflags(vcpu, CPUSTAT_WAIT); - set_bit(vcpu->vcpu_id, vcpu->kvm->arch.float_int.idle_mask); + set_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.float_int.idle_mask); }
static void __unset_cpu_idle(struct kvm_vcpu *vcpu) { kvm_s390_clear_cpuflags(vcpu, CPUSTAT_WAIT); - clear_bit(vcpu->vcpu_id, vcpu->kvm->arch.float_int.idle_mask); + clear_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.float_int.idle_mask); }
static void __reset_intercept_indicators(struct kvm_vcpu *vcpu) --- a/arch/s390/kvm/kvm-s390.h +++ b/arch/s390/kvm/kvm-s390.h @@ -67,7 +67,7 @@ static inline int is_vcpu_stopped(struct
static inline int is_vcpu_idle(struct kvm_vcpu *vcpu) { - return test_bit(vcpu->vcpu_id, vcpu->kvm->arch.float_int.idle_mask); + return test_bit(kvm_vcpu_get_idx(vcpu), vcpu->kvm->arch.float_int.idle_mask); }
static inline int kvm_is_ucontrol(struct kvm *kvm)