+++ /dev/null
-// 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);
-
- vcpu->arch.vgic_cpu.vgic_v3.its_vpe.pending_last = true;
- 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;
- int 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);
-}
-
-/**
- * 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 i, nr_vcpus, ret;
-
- 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);
- 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;
-}
-
-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;
- 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);
-
-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;
-}
projects / linux-2.6-block.git / blobdiff