OSCL-LXR linux-6.0.1/​arch/​arm64/​kvm/​vgic/​vgic-v4.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2017 ARM Ltd.
  * Author: Marc Zyngier <marc.zyngier@arm.com>
  */
 
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/kvm_host.h>
 #include <linux/irqchip/arm-gic-v3.h>
 
 #include "vgic.h"
 
 /*
  * How KVM uses GICv4 (insert rude comments here):
  *
  * The vgic-v4 layer acts as a bridge between several entities:
  * - The GICv4 ITS representation offered by the ITS driver
  * - VFIO, which is in charge of the PCI endpoint
  * - The virtual ITS, which is the only thing the guest sees
  *
  * The configuration of VLPIs is triggered by a callback from VFIO,
  * instructing KVM that a PCI device has been configured to deliver
  * MSIs to a vITS.
  *
  * kvm_vgic_v4_set_forwarding() is thus called with the routing entry,
  * and this is used to find the corresponding vITS data structures
  * (ITS instance, device, event and irq) using a process that is
  * extremely similar to the injection of an MSI.
  *
  * At this stage, we can link the guest's view of an LPI (uniquely
  * identified by the routing entry) and the host irq, using the GICv4
  * driver mapping operation. Should the mapping succeed, we've then
  * successfully upgraded the guest's LPI to a VLPI. We can then start
  * with updating GICv4's view of the property table and generating an
  * INValidation in order to kickstart the delivery of this VLPI to the
  * guest directly, without software intervention. Well, almost.
  *
  * When the PCI endpoint is deconfigured, this operation is reversed
  * with VFIO calling kvm_vgic_v4_unset_forwarding().
  *
  * Once the VLPI has been mapped, it needs to follow any change the
  * guest performs on its LPI through the vITS. For that, a number of
  * command handlers have hooks to communicate these changes to the HW:
  * - Any invalidation triggers a call to its_prop_update_vlpi()
  * - The INT command results in a irq_set_irqchip_state(), which
  *   generates an INT on the corresponding VLPI.
  * - The CLEAR command results in a irq_set_irqchip_state(), which
  *   generates an CLEAR on the corresponding VLPI.
  * - DISCARD translates into an unmap, similar to a call to
  *   kvm_vgic_v4_unset_forwarding().
  * - MOVI is translated by an update of the existing mapping, changing
  *   the target vcpu, resulting in a VMOVI being generated.
  * - MOVALL is translated by a string of mapping updates (similar to
  *   the handling of MOVI). MOVALL is horrible.
  *
  * Note that a DISCARD/MAPTI sequence emitted from the guest without
  * reprogramming the PCI endpoint after MAPTI does not result in a
  * VLPI being mapped, as there is no callback from VFIO (the guest
  * will get the interrupt via the normal SW injection). Fixing this is
  * not trivial, and requires some horrible messing with the VFIO
  * internals. Not fun. Don't do that.
  *
  * Then there is the scheduling. Each time a vcpu is about to run on a
  * physical CPU, KVM must tell the corresponding redistributor about
  * it. And if we've migrated our vcpu from one CPU to another, we must
  * tell the ITS (so that the messages reach the right redistributor).
  * This is done in two steps: first issue a irq_set_affinity() on the
  * irq corresponding to the vcpu, then call its_make_vpe_resident().
  * You must be in a non-preemptible context. On exit, a call to
  * its_make_vpe_non_resident() tells the redistributor that we're done
  * with the vcpu.
  *
  * Finally, the doorbell handling: Each vcpu is allocated an interrupt
  * which will fire each time a VLPI is made pending whilst the vcpu is
  * not running. Each time the vcpu gets blocked, the doorbell
  * interrupt gets enabled. When the vcpu is unblocked (for whatever
  * reason), the doorbell interrupt is disabled.
  */
 
 #define DB_IRQ_FLAGS    (IRQ_NOAUTOEN | IRQ_DISABLE_UNLAZY | IRQ_NO_BALANCING)
 
 static irqreturn_t vgic_v4_doorbell_handler(int irq, void *info)
 {
     struct kvm_vcpu *vcpu = info;
 
     /* We got the message, no need to fire again */
     if (!kvm_vgic_global_state.has_gicv4_1 &&
         !irqd_irq_disabled(&irq_to_desc(irq)->irq_data))
         disable_irq_nosync(irq);
 
     /*
      * The v4.1 doorbell can fire concurrently with the vPE being
      * made non-resident. Ensure we only update pending_last
      * *after* the non-residency sequence has completed.
      */
     raw_spin_lock(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vpe_lock);
     vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
     raw_spin_unlock(&vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vpe_lock);
 
     kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu);
     kvm_vcpu_kick(vcpu);
 
     return IRQ_HANDLED;
 }
 
 static void vgic_v4_sync_sgi_config(struct its_vpe *vpe, struct vgic_irq *irq)
 {
     vpe->sgi_config[irq->intid].enabled = irq->enabled;
     vpe->sgi_config[irq->intid].group   = irq->group;
     vpe->sgi_config[irq->intid].priority    = irq->priority;
 }
 
 static void vgic_v4_enable_vsgis(struct kvm_vcpu *vcpu)
 {
     struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
     int i;
 
     /*
      * With GICv4.1, every virtual SGI can be directly injected. So
      * let's pretend that they are HW interrupts, tied to a host
      * IRQ. The SGI code will do its magic.
      */
     for (i = 0; i < VGIC_NR_SGIS; i++) {
         struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, i);
         struct irq_desc *desc;
         unsigned long flags;
         int ret;
 
         raw_spin_lock_irqsave(&irq->irq_lock, flags);
 
         if (irq->hw)
             goto unlock;
 
         irq->hw = true;
         irq->host_irq = irq_find_mapping(vpe->sgi_domain, i);
 
         /* Transfer the full irq state to the vPE */
         vgic_v4_sync_sgi_config(vpe, irq);
         desc = irq_to_desc(irq->host_irq);
         ret = irq_domain_activate_irq(irq_desc_get_irq_data(desc),
                           false);
         if (!WARN_ON(ret)) {
             /* Transfer pending state */
             ret = irq_set_irqchip_state(irq->host_irq,
                             IRQCHIP_STATE_PENDING,
                             irq->pending_latch);
             WARN_ON(ret);
             irq->pending_latch = false;
         }
     unlock:
         raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
         vgic_put_irq(vcpu->kvm, irq);
     }
 }
 
 static void vgic_v4_disable_vsgis(struct kvm_vcpu *vcpu)
 {
     int i;
 
     for (i = 0; i < VGIC_NR_SGIS; i++) {
         struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, i);
         struct irq_desc *desc;
         unsigned long flags;
         int ret;
 
         raw_spin_lock_irqsave(&irq->irq_lock, flags);
 
         if (!irq->hw)
             goto unlock;
 
         irq->hw = false;
         ret = irq_get_irqchip_state(irq->host_irq,
                         IRQCHIP_STATE_PENDING,
                         &irq->pending_latch);
         WARN_ON(ret);
 
         desc = irq_to_desc(irq->host_irq);
         irq_domain_deactivate_irq(irq_desc_get_irq_data(desc));
     unlock:
         raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
         vgic_put_irq(vcpu->kvm, irq);
     }
 }
 
 /* Must be called with the kvm lock held */
 void vgic_v4_configure_vsgis(struct kvm *kvm)
 {
     struct vgic_dist *dist = &kvm->arch.vgic;
     struct kvm_vcpu *vcpu;
     unsigned long i;
 
     kvm_arm_halt_guest(kvm);
 
     kvm_for_each_vcpu(i, vcpu, kvm) {
         if (dist->nassgireq)
             vgic_v4_enable_vsgis(vcpu);
         else
             vgic_v4_disable_vsgis(vcpu);
     }
 
     kvm_arm_resume_guest(kvm);
 }
 
 /*
  * Must be called with GICv4.1 and the vPE unmapped, which
  * indicates the invalidation of any VPT caches associated
  * with the vPE, thus we can get the VLPI state by peeking
  * at the VPT.
  */
 void vgic_v4_get_vlpi_state(struct vgic_irq *irq, bool *val)
 {
     struct its_vpe *vpe = &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
     int mask = BIT(irq->intid % BITS_PER_BYTE);
     void *va;
     u8 *ptr;
 
     va = page_address(vpe->vpt_page);
     ptr = va + irq->intid / BITS_PER_BYTE;
 
     *val = !!(*ptr & mask);
 }
 
 /**
  * vgic_v4_init - Initialize the GICv4 data structures
  * @kvm:    Pointer to the VM being initialized
  *
  * We may be called each time a vITS is created, or when the
  * vgic is initialized. This relies on kvm->lock to be
  * held. In both cases, the number of vcpus should now be
  * fixed.
  */
 int vgic_v4_init(struct kvm *kvm)
 {
     struct vgic_dist *dist = &kvm->arch.vgic;
     struct kvm_vcpu *vcpu;
     int nr_vcpus, ret;
     unsigned long i;
 
     if (!kvm_vgic_global_state.has_gicv4)
         return 0; /* Nothing to see here... move along. */
 
     if (dist->its_vm.vpes)
         return 0;
 
     nr_vcpus = atomic_read(&kvm->online_vcpus);
 
     dist->its_vm.vpes = kcalloc(nr_vcpus, sizeof(*dist->its_vm.vpes),
                     GFP_KERNEL_ACCOUNT);
     if (!dist->its_vm.vpes)
         return -ENOMEM;
 
     dist->its_vm.nr_vpes = nr_vcpus;
 
     kvm_for_each_vcpu(i, vcpu, kvm)
         dist->its_vm.vpes[i] = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
 
     ret = its_alloc_vcpu_irqs(&dist->its_vm);
     if (ret < 0) {
         kvm_err("VPE IRQ allocation failure\n");
         kfree(dist->its_vm.vpes);
         dist->its_vm.nr_vpes = 0;
         dist->its_vm.vpes = NULL;
         return ret;
     }
 
     kvm_for_each_vcpu(i, vcpu, kvm) {
         int irq = dist->its_vm.vpes[i]->irq;
         unsigned long irq_flags = DB_IRQ_FLAGS;
 
         /*
          * Don't automatically enable the doorbell, as we're
          * flipping it back and forth when the vcpu gets
          * blocked. Also disable the lazy disabling, as the
          * doorbell could kick us out of the guest too
          * early...
          *
          * On GICv4.1, the doorbell is managed in HW and must
          * be left enabled.
          */
         if (kvm_vgic_global_state.has_gicv4_1)
             irq_flags &= ~IRQ_NOAUTOEN;
         irq_set_status_flags(irq, irq_flags);
 
         ret = request_irq(irq, vgic_v4_doorbell_handler,
                   0, "vcpu", vcpu);
         if (ret) {
             kvm_err("failed to allocate vcpu IRQ%d\n", irq);
             /*
              * Trick: adjust the number of vpes so we know
              * how many to nuke on teardown...
              */
             dist->its_vm.nr_vpes = i;
             break;
         }
     }
 
     if (ret)
         vgic_v4_teardown(kvm);
 
     return ret;
 }
 
 /**
  * vgic_v4_teardown - Free the GICv4 data structures
  * @kvm:    Pointer to the VM being destroyed
  *
  * Relies on kvm->lock to be held.
  */
 void vgic_v4_teardown(struct kvm *kvm)
 {
     struct its_vm *its_vm = &kvm->arch.vgic.its_vm;
     int i;
 
     if (!its_vm->vpes)
         return;
 
     for (i = 0; i < its_vm->nr_vpes; i++) {
         struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, i);
         int irq = its_vm->vpes[i]->irq;
 
         irq_clear_status_flags(irq, DB_IRQ_FLAGS);
         free_irq(irq, vcpu);
     }
 
     its_free_vcpu_irqs(its_vm);
     kfree(its_vm->vpes);
     its_vm->nr_vpes = 0;
     its_vm->vpes = NULL;
 }
 
 int vgic_v4_put(struct kvm_vcpu *vcpu, bool need_db)
 {
     struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
 
     if (!vgic_supports_direct_msis(vcpu->kvm) || !vpe->resident)
         return 0;
 
     return its_make_vpe_non_resident(vpe, need_db);
 }
 
 int vgic_v4_load(struct kvm_vcpu *vcpu)
 {
     struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
     int err;
 
     if (!vgic_supports_direct_msis(vcpu->kvm) || vpe->resident)
         return 0;
 
     /*
      * Before making the VPE resident, make sure the redistributor
      * corresponding to our current CPU expects us here. See the
      * doc in drivers/irqchip/irq-gic-v4.c to understand how this
      * turns into a VMOVP command at the ITS level.
      */
     err = irq_set_affinity(vpe->irq, cpumask_of(smp_processor_id()));
     if (err)
         return err;
 
     err = its_make_vpe_resident(vpe, false, vcpu->kvm->arch.vgic.enabled);
     if (err)
         return err;
 
     /*
      * Now that the VPE is resident, let's get rid of a potential
      * doorbell interrupt that would still be pending. This is a
      * GICv4.0 only "feature"...
      */
     if (!kvm_vgic_global_state.has_gicv4_1)
         err = irq_set_irqchip_state(vpe->irq, IRQCHIP_STATE_PENDING, false);
 
     return err;
 }
 
 void vgic_v4_commit(struct kvm_vcpu *vcpu)
 {
     struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe;
 
     /*
      * No need to wait for the vPE to be ready across a shallow guest
      * exit, as only a vcpu_put will invalidate it.
      */
     if (!vpe->ready)
         its_commit_vpe(vpe);
 }
 
 static struct vgic_its *vgic_get_its(struct kvm *kvm,
                      struct kvm_kernel_irq_routing_entry *irq_entry)
 {
     struct kvm_msi msi  = (struct kvm_msi) {
         .address_lo = irq_entry->msi.address_lo,
         .address_hi = irq_entry->msi.address_hi,
         .data       = irq_entry->msi.data,
         .flags      = irq_entry->msi.flags,
         .devid      = irq_entry->msi.devid,
     };
 
     return vgic_msi_to_its(kvm, &msi);
 }
 
 int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
                    struct kvm_kernel_irq_routing_entry *irq_entry)
 {
     struct vgic_its *its;
     struct vgic_irq *irq;
     struct its_vlpi_map map;
     unsigned long flags;
     int ret;
 
     if (!vgic_supports_direct_msis(kvm))
         return 0;
 
     /*
      * Get the ITS, and escape early on error (not a valid
      * doorbell for any of our vITSs).
      */
     its = vgic_get_its(kvm, irq_entry);
     if (IS_ERR(its))
         return 0;
 
     mutex_lock(&its->its_lock);
 
     /* Perform the actual DevID/EventID -> LPI translation. */
     ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
                    irq_entry->msi.data, &irq);
     if (ret)
         goto out;
 
     /*
      * Emit the mapping request. If it fails, the ITS probably
      * isn't v4 compatible, so let's silently bail out. Holding
      * the ITS lock should ensure that nothing can modify the
      * target vcpu.
      */
     map = (struct its_vlpi_map) {
         .vm     = &kvm->arch.vgic.its_vm,
         .vpe        = &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
         .vintid     = irq->intid,
         .properties = ((irq->priority & 0xfc) |
                    (irq->enabled ? LPI_PROP_ENABLED : 0) |
                    LPI_PROP_GROUP1),
         .db_enabled = true,
     };
 
     ret = its_map_vlpi(virq, &map);
     if (ret)
         goto out;
 
     irq->hw     = true;
     irq->host_irq   = virq;
     atomic_inc(&map.vpe->vlpi_count);
 
     /* Transfer pending state */
     raw_spin_lock_irqsave(&irq->irq_lock, flags);
     if (irq->pending_latch) {
         ret = irq_set_irqchip_state(irq->host_irq,
                         IRQCHIP_STATE_PENDING,
                         irq->pending_latch);
         WARN_RATELIMIT(ret, "IRQ %d", irq->host_irq);
 
         /*
          * Clear pending_latch and communicate this state
          * change via vgic_queue_irq_unlock.
          */
         irq->pending_latch = false;
         vgic_queue_irq_unlock(kvm, irq, flags);
     } else {
         raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
     }
 
 out:
     mutex_unlock(&its->its_lock);
     return ret;
 }
 
 int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
                  struct kvm_kernel_irq_routing_entry *irq_entry)
 {
     struct vgic_its *its;
     struct vgic_irq *irq;
     int ret;
 
     if (!vgic_supports_direct_msis(kvm))
         return 0;
 
     /*
      * Get the ITS, and escape early on error (not a valid
      * doorbell for any of our vITSs).
      */
     its = vgic_get_its(kvm, irq_entry);
     if (IS_ERR(its))
         return 0;
 
     mutex_lock(&its->its_lock);
 
     ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
                    irq_entry->msi.data, &irq);
     if (ret)
         goto out;
 
     WARN_ON(!(irq->hw && irq->host_irq == virq));
     if (irq->hw) {
         atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count);
         irq->hw = false;
         ret = its_unmap_vlpi(virq);
     }
 
 out:
     mutex_unlock(&its->its_lock);
     return ret;
 }

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