Commit 3802411d authored by Andre Przywara's avatar Andre Przywara Committed by Marc Zyngier

KVM: arm64: vgic-its: Connect LPIs to the VGIC emulation

LPIs are dynamically created (mapped) at guest runtime and their
actual number can be quite high, but is mostly assigned using a very
sparse allocation scheme. So arrays are not an ideal data structure
to hold the information.
We use a spin-lock protected linked list to hold all mapped LPIs,
represented by their struct vgic_irq. This lock is grouped between the
ap_list_lock and the vgic_irq lock in our locking order.
Also we store a pointer to that struct vgic_irq in our struct its_itte,
so we can easily access it.
Eventually we call our new vgic_get_lpi() from vgic_get_irq(), so
the VGIC code gets transparently access to LPIs.
Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Reviewed-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Tested-by: default avatarEric Auger <eric.auger@redhat.com>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 424c3383
......@@ -77,6 +77,7 @@ enum vgic_irq_config {
struct vgic_irq {
spinlock_t irq_lock; /* Protects the content of the struct */
struct list_head lpi_list; /* Used to link all LPIs together */
struct list_head ap_list;
struct kvm_vcpu *vcpu; /* SGIs and PPIs: The VCPU
......@@ -193,6 +194,11 @@ struct vgic_dist {
* GICv3 spec: 6.1.2 "LPI Configuration tables"
*/
u64 propbaser;
/* Protects the lpi_list and the count value below. */
spinlock_t lpi_list_lock;
struct list_head lpi_list_head;
int lpi_list_count;
};
struct vgic_v2_cpu_if {
......
......@@ -157,6 +157,9 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
struct kvm_vcpu *vcpu0 = kvm_get_vcpu(kvm, 0);
int i;
INIT_LIST_HEAD(&dist->lpi_list_head);
spin_lock_init(&dist->lpi_list_lock);
dist->spis = kcalloc(nr_spis, sizeof(struct vgic_irq), GFP_KERNEL);
if (!dist->spis)
return -ENOMEM;
......
......@@ -56,6 +56,7 @@ struct its_collection {
struct its_itte {
struct list_head itte_list;
struct vgic_irq *irq;
struct its_collection *collection;
u32 lpi;
u32 event_id;
......@@ -148,6 +149,10 @@ static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
static void its_free_itte(struct kvm *kvm, struct its_itte *itte)
{
list_del(&itte->itte_list);
/* This put matches the get in vgic_add_lpi. */
vgic_put_irq(kvm, itte->irq);
kfree(itte);
}
......
......@@ -81,6 +81,8 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
else
intid = val & GICH_LR_VIRTUALID;
irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
if (!irq) /* An LPI could have been unmapped. */
continue;
spin_lock(&irq->irq_lock);
......
......@@ -36,7 +36,8 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state;
* its->cmd_lock (mutex)
* its->its_lock (mutex)
* vgic_cpu->ap_list_lock
* vgic_irq->irq_lock
* kvm->lpi_list_lock
* vgic_irq->irq_lock
*
* If you need to take multiple locks, always take the upper lock first,
* then the lower ones, e.g. first take the its_lock, then the irq_lock.
......@@ -51,6 +52,41 @@ struct vgic_global __section(.hyp.text) kvm_vgic_global_state;
* spin_lock(vcpuY->arch.vgic_cpu.ap_list_lock);
*/
/*
* Iterate over the VM's list of mapped LPIs to find the one with a
* matching interrupt ID and return a reference to the IRQ structure.
*/
static struct vgic_irq *vgic_get_lpi(struct kvm *kvm, u32 intid)
{
struct vgic_dist *dist = &kvm->arch.vgic;
struct vgic_irq *irq = NULL;
spin_lock(&dist->lpi_list_lock);
list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
if (irq->intid != intid)
continue;
/*
* This increases the refcount, the caller is expected to
* call vgic_put_irq() later once it's finished with the IRQ.
*/
kref_get(&irq->refcount);
goto out_unlock;
}
irq = NULL;
out_unlock:
spin_unlock(&dist->lpi_list_lock);
return irq;
}
/*
* This looks up the virtual interrupt ID to get the corresponding
* struct vgic_irq. It also increases the refcount, so any caller is expected
* to call vgic_put_irq() once it's finished with this IRQ.
*/
struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
u32 intid)
{
......@@ -62,9 +98,9 @@ struct vgic_irq *vgic_get_irq(struct kvm *kvm, struct kvm_vcpu *vcpu,
if (intid <= VGIC_MAX_SPI)
return &kvm->arch.vgic.spis[intid - VGIC_NR_PRIVATE_IRQS];
/* LPIs are not yet covered */
/* LPIs */
if (intid >= VGIC_MIN_LPI)
return NULL;
return vgic_get_lpi(kvm, intid);
WARN(1, "Looking up struct vgic_irq for reserved INTID");
return NULL;
......@@ -78,18 +114,33 @@ static void vgic_get_irq_kref(struct vgic_irq *irq)
kref_get(&irq->refcount);
}
/* The refcount should never drop to 0 at the moment. */
/*
* We can't do anything in here, because we lack the kvm pointer to
* lock and remove the item from the lpi_list. So we keep this function
* empty and use the return value of kref_put() to trigger the freeing.
*/
static void vgic_irq_release(struct kref *ref)
{
WARN_ON(1);
}
void vgic_put_irq(struct kvm *kvm, struct vgic_irq *irq)
{
struct vgic_dist *dist;
if (irq->intid < VGIC_MIN_LPI)
return;
kref_put(&irq->refcount, vgic_irq_release);
if (!kref_put(&irq->refcount, vgic_irq_release))
return;
dist = &kvm->arch.vgic;
spin_lock(&dist->lpi_list_lock);
list_del(&irq->lpi_list);
dist->lpi_list_count--;
spin_unlock(&dist->lpi_list_lock);
kfree(irq);
}
/**
......
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