]> git.ipfire.org Git - thirdparty/kernel/stable.git/commitdiff
KVM: x86: Dedup AVIC vs. PI code for identifying target vCPU
authorSean Christopherson <seanjc@google.com>
Wed, 11 Jun 2025 22:45:31 +0000 (15:45 -0700)
committerSean Christopherson <seanjc@google.com>
Mon, 23 Jun 2025 16:50:29 +0000 (09:50 -0700)
Hoist the logic for identifying the target vCPU for a posted interrupt
into common x86.  The code is functionally identical between Intel and
AMD.

Tested-by: Sairaj Kodilkar <sarunkod@amd.com>
Link: https://lore.kernel.org/r/20250611224604.313496-30-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
arch/x86/include/asm/kvm_host.h
arch/x86/kvm/irq.c
arch/x86/kvm/svm/avic.c
arch/x86/kvm/svm/svm.h
arch/x86/kvm/vmx/posted_intr.c
arch/x86/kvm/vmx/posted_intr.h

index 30b3ecc01684fcf40eb157648d7bd984616efc34..f91791473f0bd6fb49b5c29a4722f068c1f721e8 100644 (file)
@@ -1855,7 +1855,7 @@ struct kvm_x86_ops {
 
        int (*pi_update_irte)(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                              unsigned int host_irq, uint32_t guest_irq,
-                             struct kvm_kernel_irq_routing_entry *new);
+                             struct kvm_vcpu *vcpu, u32 vector);
        void (*pi_start_assignment)(struct kvm *kvm);
        void (*apicv_pre_state_restore)(struct kvm_vcpu *vcpu);
        void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu);
index b3ae9e43a25475e93cc52d23916377b2495130ec..6a407a958af7c6768e475e8dd075a35d7a2f46f9 100644 (file)
@@ -508,6 +508,42 @@ void kvm_arch_irq_routing_update(struct kvm *kvm)
                kvm_make_scan_ioapic_request(kvm);
 }
 
+static int kvm_pi_update_irte(struct kvm_kernel_irqfd *irqfd,
+                             struct kvm_kernel_irq_routing_entry *entry)
+{
+       struct kvm *kvm = irqfd->kvm;
+       struct kvm_vcpu *vcpu = NULL;
+       struct kvm_lapic_irq irq;
+
+       if (!irqchip_in_kernel(kvm) ||
+           !kvm_arch_has_irq_bypass() ||
+           !kvm_arch_has_assigned_device(kvm))
+               return 0;
+
+       if (entry && entry->type == KVM_IRQ_ROUTING_MSI) {
+               kvm_set_msi_irq(kvm, entry, &irq);
+
+               /*
+                * Force remapped mode if hardware doesn't support posting the
+                * virtual interrupt to a vCPU.  Only IRQs are postable (NMIs,
+                * SMIs, etc. are not), and neither AMD nor Intel IOMMUs support
+                * posting multicast/broadcast IRQs.  If the interrupt can't be
+                * posted, the device MSI needs to be routed to the host so that
+                * the guest's desired interrupt can be synthesized by KVM.
+                *
+                * This means that KVM can only post lowest-priority interrupts
+                * if they have a single CPU as the destination, e.g. only if
+                * the guest has affined the interrupt to a single vCPU.
+                */
+               if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu) ||
+                   !kvm_irq_is_postable(&irq))
+                       vcpu = NULL;
+       }
+
+       return kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, irqfd->producer->irq,
+                                           irqfd->gsi, vcpu, irq.vector);
+}
+
 int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
                                      struct irq_bypass_producer *prod)
 {
@@ -522,8 +558,7 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
        irqfd->producer = prod;
 
        if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
-               ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
-                                                  irqfd->gsi, &irqfd->irq_entry);
+               ret = kvm_pi_update_irte(irqfd, &irqfd->irq_entry);
                if (ret)
                        kvm_arch_end_assignment(irqfd->kvm);
        }
@@ -551,8 +586,7 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
        spin_lock_irq(&kvm->irqfds.lock);
 
        if (irqfd->irq_entry.type == KVM_IRQ_ROUTING_MSI) {
-               ret = kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, prod->irq,
-                                                  irqfd->gsi, NULL);
+               ret = kvm_pi_update_irte(irqfd, NULL);
                if (ret)
                        pr_info("irq bypass consumer (eventfd %p) unregistration fails: %d\n",
                                irqfd->consumer.eventfd, ret);
@@ -568,8 +602,7 @@ int kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
                                  struct kvm_kernel_irq_routing_entry *old,
                                  struct kvm_kernel_irq_routing_entry *new)
 {
-       return kvm_x86_call(pi_update_irte)(irqfd, irqfd->kvm, irqfd->producer->irq,
-                                           irqfd->gsi, new);
+       return kvm_pi_update_irte(irqfd, new);
 }
 
 bool kvm_arch_irqfd_route_changed(struct kvm_kernel_irq_routing_entry *old,
index 86d2dc7c1940fc5d9396065e2e065215573e72d1..153d8a84b8efd4f1c0c784cfe0f13defaa564314 100644 (file)
@@ -804,52 +804,12 @@ static int svm_ir_list_add(struct vcpu_svm *svm,
        return 0;
 }
 
-/*
- * Note:
- * The HW cannot support posting multicast/broadcast
- * interrupts to a vCPU. So, we still use legacy interrupt
- * remapping for these kind of interrupts.
- *
- * For lowest-priority interrupts, we only support
- * those with single CPU as the destination, e.g. user
- * configures the interrupts via /proc/irq or uses
- * irqbalance to make the interrupts single-CPU.
- */
-static int
-get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
-                struct vcpu_data *vcpu_info, struct kvm_vcpu **vcpu)
-{
-       struct kvm_lapic_irq irq;
-       *vcpu = NULL;
-
-       kvm_set_msi_irq(kvm, e, &irq);
-
-       if (!kvm_intr_is_single_vcpu(kvm, &irq, vcpu) ||
-           !kvm_irq_is_postable(&irq)) {
-               pr_debug("SVM: %s: use legacy intr remap mode for irq %u\n",
-                        __func__, irq.vector);
-               return -1;
-       }
-
-       pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
-                irq.vector);
-       vcpu_info->vector = irq.vector;
-
-       return 0;
-}
-
 int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                        unsigned int host_irq, uint32_t guest_irq,
-                       struct kvm_kernel_irq_routing_entry *new)
+                       struct kvm_vcpu *vcpu, u32 vector)
 {
-       bool enable_remapped_mode = true;
-       struct vcpu_data vcpu_info;
-       struct kvm_vcpu *vcpu = NULL;
        int ret = 0;
 
-       if (!kvm_arch_has_assigned_device(kvm) || !kvm_arch_has_irq_bypass())
-               return 0;
-
        /*
         * If the IRQ was affined to a different vCPU, remove the IRTE metadata
         * from the *previous* vCPU's list.
@@ -857,7 +817,7 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
        svm_ir_list_del(irqfd);
 
        pr_debug("SVM: %s: host_irq=%#x, guest_irq=%#x, set=%#x\n",
-                __func__, host_irq, guest_irq, !!new);
+                __func__, host_irq, guest_irq, !!vcpu);
 
        /**
         * Here, we setup with legacy mode in the following cases:
@@ -866,23 +826,23 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
         * 3. APIC virtualization is disabled for the vcpu.
         * 4. IRQ has incompatible delivery mode (SMI, INIT, etc)
         */
-       if (new && new->type == KVM_IRQ_ROUTING_MSI &&
-           !get_pi_vcpu_info(kvm, new, &vcpu_info, &vcpu) &&
-           kvm_vcpu_apicv_active(vcpu)) {
-               struct amd_iommu_pi_data pi;
-
-               enable_remapped_mode = false;
-
-               vcpu_info.pi_desc_addr = avic_get_backing_page_address(to_svm(vcpu));
-
+       if (vcpu && kvm_vcpu_apicv_active(vcpu)) {
                /*
                 * Try to enable guest_mode in IRTE.  Note, the address
                 * of the vCPU's AVIC backing page is passed to the
                 * IOMMU via vcpu_info->pi_desc_addr.
                 */
-               pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id, vcpu->vcpu_id);
-               pi.is_guest_mode = true;
-               pi.vcpu_data = &vcpu_info;
+               struct vcpu_data vcpu_info = {
+                       .pi_desc_addr = avic_get_backing_page_address(to_svm(vcpu)),
+                       .vector = vector,
+               };
+
+               struct amd_iommu_pi_data pi = {
+                       .ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id, vcpu->vcpu_id),
+                       .is_guest_mode = true,
+                       .vcpu_data = &vcpu_info,
+               };
+
                ret = irq_set_vcpu_affinity(host_irq, &pi);
 
                /**
@@ -894,12 +854,11 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                 */
                if (!ret)
                        ret = svm_ir_list_add(to_svm(vcpu), irqfd, &pi);
-       }
 
-       if (!ret && vcpu) {
-               trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id,
-                                        guest_irq, vcpu_info.vector,
-                                        vcpu_info.pi_desc_addr, !!new);
+               trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id, guest_irq,
+                                        vector, vcpu_info.pi_desc_addr, true);
+       } else {
+               ret = irq_set_vcpu_affinity(host_irq, NULL);
        }
 
        if (ret < 0) {
@@ -907,10 +866,7 @@ int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                goto out;
        }
 
-       if (enable_remapped_mode)
-               ret = irq_set_vcpu_affinity(host_irq, NULL);
-       else
-               ret = 0;
+       ret = 0;
 out:
        return ret;
 }
index 939ff0e35a2be80b5bf765340d013099b14da48c..b5cd1927b009ba0d36ec11755c451b839d3293d6 100644 (file)
@@ -747,7 +747,7 @@ void avic_apicv_post_state_restore(struct kvm_vcpu *vcpu);
 void avic_refresh_apicv_exec_ctrl(struct kvm_vcpu *vcpu);
 int avic_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                        unsigned int host_irq, uint32_t guest_irq,
-                       struct kvm_kernel_irq_routing_entry *new);
+                       struct kvm_vcpu *vcpu, u32 vector);
 void avic_vcpu_blocking(struct kvm_vcpu *vcpu);
 void avic_vcpu_unblocking(struct kvm_vcpu *vcpu);
 void avic_ring_doorbell(struct kvm_vcpu *vcpu);
index e59eae11f476f2423e93accef3c876c6a2ee38b0..3de767c5d6b25d9ed0eebf8e15cc58b2caf79f98 100644 (file)
@@ -300,46 +300,19 @@ void vmx_pi_start_assignment(struct kvm *kvm)
 
 int vmx_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                       unsigned int host_irq, uint32_t guest_irq,
-                      struct kvm_kernel_irq_routing_entry *new)
+                      struct kvm_vcpu *vcpu, u32 vector)
 {
-       struct kvm_lapic_irq irq;
-       struct kvm_vcpu *vcpu;
-       struct vcpu_data vcpu_info;
-
-       if (!vmx_can_use_vtd_pi(kvm))
-               return 0;
-
-       /*
-        * VT-d PI cannot support posting multicast/broadcast
-        * interrupts to a vCPU, we still use interrupt remapping
-        * for these kind of interrupts.
-        *
-        * For lowest-priority interrupts, we only support
-        * those with single CPU as the destination, e.g. user
-        * configures the interrupts via /proc/irq or uses
-        * irqbalance to make the interrupts single-CPU.
-        *
-        * We will support full lowest-priority interrupt later.
-        *
-        * In addition, we can only inject generic interrupts using
-        * the PI mechanism, refuse to route others through it.
-        */
-       if (!new || new->type != KVM_IRQ_ROUTING_MSI)
-               goto do_remapping;
-
-       kvm_set_msi_irq(kvm, new, &irq);
-
-       if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu) ||
-           !kvm_irq_is_postable(&irq))
-               goto do_remapping;
-
-       vcpu_info.pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu));
-       vcpu_info.vector = irq.vector;
-
-       trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id, guest_irq,
-                                vcpu_info.vector, vcpu_info.pi_desc_addr, true);
-
-       return irq_set_vcpu_affinity(host_irq, &vcpu_info);
-do_remapping:
-       return irq_set_vcpu_affinity(host_irq, NULL);
+       if (vcpu) {
+               struct vcpu_data vcpu_info = {
+                       .pi_desc_addr = __pa(vcpu_to_pi_desc(vcpu)),
+                       .vector = vector,
+               };
+
+               trace_kvm_pi_irte_update(host_irq, vcpu->vcpu_id, guest_irq,
+                                        vcpu_info.vector, vcpu_info.pi_desc_addr, true);
+
+               return irq_set_vcpu_affinity(host_irq, &vcpu_info);
+       } else {
+               return irq_set_vcpu_affinity(host_irq, NULL);
+       }
 }
index a94afcb55f7ffb1a9b3a37b6e40bc4a84e76056a..94ed66ea6249cd87b83d78524f600f76461f1bd9 100644 (file)
@@ -16,7 +16,7 @@ void pi_apicv_pre_state_restore(struct kvm_vcpu *vcpu);
 bool pi_has_pending_interrupt(struct kvm_vcpu *vcpu);
 int vmx_pi_update_irte(struct kvm_kernel_irqfd *irqfd, struct kvm *kvm,
                       unsigned int host_irq, uint32_t guest_irq,
-                      struct kvm_kernel_irq_routing_entry *new);
+                      struct kvm_vcpu *vcpu, u32 vector);
 void vmx_pi_start_assignment(struct kvm *kvm);
 
 static inline int pi_find_highest_vector(struct pi_desc *pi_desc)