diff options
| -rw-r--r-- | arch/x86/kvm/svm/avic.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c index 8e041b215ddb..2092db892d7d 100644 --- a/arch/x86/kvm/svm/avic.c +++ b/arch/x86/kvm/svm/avic.c @@ -791,6 +791,7 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi) int ret = 0; unsigned long flags; struct amd_svm_iommu_ir *ir; + u64 entry; /** * In some cases, the existing irte is updated and re-set, @@ -824,6 +825,18 @@ static int svm_ir_list_add(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi) ir->data = pi->ir_data; spin_lock_irqsave(&svm->ir_list_lock, flags); + + /* + * Update the target pCPU for IOMMU doorbells if the vCPU is running. + * If the vCPU is NOT running, i.e. is blocking or scheduled out, KVM + * will update the pCPU info when the vCPU awkened and/or scheduled in. + * See also avic_vcpu_load(). + */ + entry = READ_ONCE(*(svm->avic_physical_id_cache)); + if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK) + amd_iommu_update_ga(entry & AVIC_PHYSICAL_ID_ENTRY_HOST_PHYSICAL_ID_MASK, + true, pi->ir_data); + list_add(&ir->node, &svm->ir_list); spin_unlock_irqrestore(&svm->ir_list_lock, flags); out: @@ -1031,6 +1044,13 @@ void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu) if (kvm_vcpu_is_blocking(vcpu)) return; + /* + * Grab the per-vCPU interrupt remapping lock even if the VM doesn't + * _currently_ have assigned devices, as that can change. Holding + * ir_list_lock ensures that either svm_ir_list_add() will consume + * up-to-date entry information, or that this task will wait until + * svm_ir_list_add() completes to set the new target pCPU. + */ spin_lock_irqsave(&svm->ir_list_lock, flags); entry = READ_ONCE(*(svm->avic_physical_id_cache)); @@ -1067,6 +1087,14 @@ void avic_vcpu_put(struct kvm_vcpu *vcpu) if (!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK)) return; + /* + * Take and hold the per-vCPU interrupt remapping lock while updating + * the Physical ID entry even though the lock doesn't protect against + * multiple writers (see above). Holding ir_list_lock ensures that + * either svm_ir_list_add() will consume up-to-date entry information, + * or that this task will wait until svm_ir_list_add() completes to + * mark the vCPU as not running. + */ spin_lock_irqsave(&svm->ir_list_lock, flags); avic_update_iommu_vcpu_affinity(vcpu, -1, 0); |