[PATCH v4 06/11] KVM: arm/arm64: vgic: Allow dynamic mapping of physical/virtual interrupts
Marc Zyngier
marc.zyngier at arm.com
Fri Aug 7 08:45:42 PDT 2015
In order to be able to feed physical interrupts to a guest, we need
to be able to establish the virtual-physical mapping between the two
worlds.
The mappings are kept in a set of RCU lists, indexed by virtual interrupts.
Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
---
arch/arm/kvm/arm.c | 2 +
include/kvm/arm_vgic.h | 25 ++++++
virt/kvm/arm/vgic.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 235 insertions(+), 1 deletion(-)
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index f1bf418..ce404a5 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -125,6 +125,7 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
if (ret)
goto out_free_stage2_pgd;
+ kvm_vgic_early_init(kvm);
kvm_timer_init(kvm);
/* Mark the initial VMID generation invalid */
@@ -249,6 +250,7 @@ out:
void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu)
{
+ kvm_vgic_vcpu_early_init(vcpu);
}
void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index a881e39..c0e6354 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -159,6 +159,19 @@ struct vgic_io_device {
struct kvm_io_device dev;
};
+struct irq_phys_map {
+ u32 virt_irq;
+ u32 phys_irq;
+ u32 irq;
+ bool active;
+};
+
+struct irq_phys_map_entry {
+ struct list_head entry;
+ struct rcu_head rcu;
+ struct irq_phys_map map;
+};
+
struct vgic_dist {
spinlock_t lock;
bool in_kernel;
@@ -256,6 +269,10 @@ struct vgic_dist {
struct vgic_vm_ops vm_ops;
struct vgic_io_device dist_iodev;
struct vgic_io_device *redist_iodevs;
+
+ /* Virtual irq to hwirq mapping */
+ spinlock_t irq_phys_map_lock;
+ struct list_head irq_phys_map_list;
};
struct vgic_v2_cpu_if {
@@ -307,6 +324,9 @@ struct vgic_cpu {
struct vgic_v2_cpu_if vgic_v2;
struct vgic_v3_cpu_if vgic_v3;
};
+
+ /* Protected by the distributor's irq_phys_map_lock */
+ struct list_head irq_phys_map_list;
};
#define LR_EMPTY 0xff
@@ -321,8 +341,10 @@ int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
int kvm_vgic_hyp_init(void);
int kvm_vgic_map_resources(struct kvm *kvm);
int kvm_vgic_get_max_vcpus(void);
+void kvm_vgic_early_init(struct kvm *kvm);
int kvm_vgic_create(struct kvm *kvm, u32 type);
void kvm_vgic_destroy(struct kvm *kvm);
+void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu);
void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu);
void kvm_vgic_flush_hwstate(struct kvm_vcpu *vcpu);
void kvm_vgic_sync_hwstate(struct kvm_vcpu *vcpu);
@@ -331,6 +353,9 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu);
+struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
+ int virt_irq, int irq);
+int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, struct irq_phys_map *map);
#define irqchip_in_kernel(k) (!!((k)->arch.vgic.in_kernel))
#define vgic_initialized(k) (!!((k)->arch.vgic.nr_cpus))
diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
index 5bd1695..51c9900 100644
--- a/virt/kvm/arm/vgic.c
+++ b/virt/kvm/arm/vgic.c
@@ -24,6 +24,7 @@
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
+#include <linux/rculist.h>
#include <linux/uaccess.h>
#include <asm/kvm_emulate.h>
@@ -74,6 +75,28 @@
* cause the interrupt to become inactive in such a situation.
* Conversely, writes to GICD_ICPENDRn do not cause the interrupt to become
* inactive as long as the external input line is held high.
+ *
+ *
+ * Initialization rules: there are multiple stages to the vgic
+ * initialization, both for the distributor and the CPU interfaces.
+ *
+ * Distributor:
+ *
+ * - kvm_vgic_early_init(): initialization of static data that doesn't
+ * depend on any sizing information or emulation type. No allocation
+ * is allowed there.
+ *
+ * - vgic_init(): allocation and initialization of the generic data
+ * structures that depend on sizing information (number of CPUs,
+ * number of interrupts). Also initializes the vcpu specific data
+ * structures. Can be executed lazily for GICv2.
+ * [to be renamed to kvm_vgic_init??]
+ *
+ * CPU Interface:
+ *
+ * - kvm_vgic_cpu_early_init(): initialization of static data that
+ * doesn't depend on any sizing information or emulation type. No
+ * allocation is allowed there.
*/
#include "vgic.h"
@@ -82,6 +105,8 @@ static void vgic_retire_disabled_irqs(struct kvm_vcpu *vcpu);
static void vgic_retire_lr(int lr_nr, int irq, struct kvm_vcpu *vcpu);
static struct vgic_lr vgic_get_lr(const struct kvm_vcpu *vcpu, int lr);
static void vgic_set_lr(struct kvm_vcpu *vcpu, int lr, struct vgic_lr lr_desc);
+static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu,
+ int virt_irq);
static const struct vgic_ops *vgic_ops;
static const struct vgic_params *vgic;
@@ -1583,6 +1608,164 @@ static irqreturn_t vgic_maintenance_handler(int irq, void *data)
return IRQ_HANDLED;
}
+static struct list_head *vgic_get_irq_phys_map_list(struct kvm_vcpu *vcpu,
+ int virt_irq)
+{
+ if (virt_irq < VGIC_NR_PRIVATE_IRQS)
+ return &vcpu->arch.vgic_cpu.irq_phys_map_list;
+ else
+ return &vcpu->kvm->arch.vgic.irq_phys_map_list;
+}
+
+/**
+ * kvm_vgic_map_phys_irq - map a virtual IRQ to a physical IRQ
+ * @vcpu: The VCPU pointer
+ * @virt_irq: The virtual irq number
+ * @irq: The Linux IRQ number
+ *
+ * Establish a mapping between a guest visible irq (@virt_irq) and a
+ * Linux irq (@irq). On injection, @virt_irq will be associated with
+ * the physical interrupt represented by @irq. This mapping can be
+ * established multiple times as long as the parameters are the same.
+ *
+ * Returns a valid pointer on success, and an error pointer otherwise
+ */
+struct irq_phys_map *kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu,
+ int virt_irq, int irq)
+{
+ struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+ struct list_head *root = vgic_get_irq_phys_map_list(vcpu, virt_irq);
+ struct irq_phys_map *map;
+ struct irq_phys_map_entry *entry;
+ struct irq_desc *desc;
+ struct irq_data *data;
+ int phys_irq;
+
+ desc = irq_to_desc(irq);
+ if (!desc) {
+ kvm_err("%s: no interrupt descriptor\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ data = irq_desc_get_irq_data(desc);
+ while (data->parent_data)
+ data = data->parent_data;
+
+ phys_irq = data->hwirq;
+
+ /* Create a new mapping */
+ entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+ if (!entry)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock(&dist->irq_phys_map_lock);
+
+ /* Try to match an existing mapping */
+ map = vgic_irq_map_search(vcpu, virt_irq);
+ if (map) {
+ /* Make sure this mapping matches */
+ if (map->phys_irq != phys_irq ||
+ map->irq != irq)
+ map = ERR_PTR(-EINVAL);
+
+ /* Found an existing, valid mapping */
+ goto out;
+ }
+
+ map = &entry->map;
+ map->virt_irq = virt_irq;
+ map->phys_irq = phys_irq;
+ map->irq = irq;
+
+ list_add_tail_rcu(&entry->entry, root);
+
+out:
+ spin_unlock(&dist->irq_phys_map_lock);
+ /* If we've found a hit in the existing list, free the useless
+ * entry */
+ if (IS_ERR(map) || map != &entry->map)
+ kfree(entry);
+ return map;
+}
+
+static struct irq_phys_map *vgic_irq_map_search(struct kvm_vcpu *vcpu,
+ int virt_irq)
+{
+ struct list_head *root = vgic_get_irq_phys_map_list(vcpu, virt_irq);
+ struct irq_phys_map_entry *entry;
+ struct irq_phys_map *map;
+
+ rcu_read_lock();
+
+ list_for_each_entry_rcu(entry, root, entry) {
+ map = &entry->map;
+ if (map->virt_irq == virt_irq) {
+ rcu_read_unlock();
+ return map;
+ }
+ }
+
+ rcu_read_unlock();
+
+ return NULL;
+}
+
+static void vgic_free_phys_irq_map_rcu(struct rcu_head *rcu)
+{
+ struct irq_phys_map_entry *entry;
+
+ entry = container_of(rcu, struct irq_phys_map_entry, rcu);
+ kfree(entry);
+}
+
+/**
+ * kvm_vgic_unmap_phys_irq - Remove a virtual to physical IRQ mapping
+ * @vcpu: The VCPU pointer
+ * @map: The pointer to a mapping obtained through kvm_vgic_map_phys_irq
+ *
+ * Remove an existing mapping between virtual and physical interrupts.
+ */
+int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, struct irq_phys_map *map)
+{
+ struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
+ struct irq_phys_map_entry *entry;
+ struct list_head *root;
+
+ if (!map)
+ return -EINVAL;
+
+ root = vgic_get_irq_phys_map_list(vcpu, map->virt_irq);
+
+ spin_lock(&dist->irq_phys_map_lock);
+
+ list_for_each_entry(entry, root, entry) {
+ if (&entry->map == map) {
+ list_del_rcu(&entry->entry);
+ call_rcu(&entry->rcu, vgic_free_phys_irq_map_rcu);
+ break;
+ }
+ }
+
+ spin_unlock(&dist->irq_phys_map_lock);
+
+ return 0;
+}
+
+static void vgic_destroy_irq_phys_map(struct kvm *kvm, struct list_head *root)
+{
+ struct vgic_dist *dist = &kvm->arch.vgic;
+ struct irq_phys_map_entry *entry;
+
+ spin_lock(&dist->irq_phys_map_lock);
+
+ list_for_each_entry(entry, root, entry) {
+ list_del_rcu(&entry->entry);
+ call_rcu(&entry->rcu, vgic_free_phys_irq_map_rcu);
+ }
+
+ spin_unlock(&dist->irq_phys_map_lock);
+}
+
void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
@@ -1591,6 +1774,7 @@ void kvm_vgic_vcpu_destroy(struct kvm_vcpu *vcpu)
kfree(vgic_cpu->active_shared);
kfree(vgic_cpu->pend_act_shared);
kfree(vgic_cpu->vgic_irq_lr_map);
+ vgic_destroy_irq_phys_map(vcpu->kvm, &vgic_cpu->irq_phys_map_list);
vgic_cpu->pending_shared = NULL;
vgic_cpu->active_shared = NULL;
vgic_cpu->pend_act_shared = NULL;
@@ -1628,6 +1812,17 @@ static int vgic_vcpu_init_maps(struct kvm_vcpu *vcpu, int nr_irqs)
}
/**
+ * kvm_vgic_vcpu_early_init - Earliest possible per-vcpu vgic init stage
+ *
+ * No memory allocation should be performed here, only static init.
+ */
+void kvm_vgic_vcpu_early_init(struct kvm_vcpu *vcpu)
+{
+ struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
+ INIT_LIST_HEAD(&vgic_cpu->irq_phys_map_list);
+}
+
+/**
* kvm_vgic_get_max_vcpus - Get the maximum number of VCPUs allowed by HW
*
* The host's GIC naturally limits the maximum amount of VCPUs a guest
@@ -1664,6 +1859,7 @@ void kvm_vgic_destroy(struct kvm *kvm)
kfree(dist->irq_spi_target);
kfree(dist->irq_pending_on_cpu);
kfree(dist->irq_active_on_cpu);
+ vgic_destroy_irq_phys_map(kvm, &dist->irq_phys_map_list);
dist->irq_sgi_sources = NULL;
dist->irq_spi_cpu = NULL;
dist->irq_spi_target = NULL;
@@ -1787,6 +1983,18 @@ static int init_vgic_model(struct kvm *kvm, int type)
return 0;
}
+/**
+ * kvm_vgic_early_init - Earliest possible vgic initialization stage
+ *
+ * No memory allocation should be performed here, only static init.
+ */
+void kvm_vgic_early_init(struct kvm *kvm)
+{
+ spin_lock_init(&kvm->arch.vgic.lock);
+ spin_lock_init(&kvm->arch.vgic.irq_phys_map_lock);
+ INIT_LIST_HEAD(&kvm->arch.vgic.irq_phys_map_list);
+}
+
int kvm_vgic_create(struct kvm *kvm, u32 type)
{
int i, vcpu_lock_idx = -1, ret;
@@ -1832,7 +2040,6 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
if (ret)
goto out_unlock;
- spin_lock_init(&kvm->arch.vgic.lock);
kvm->arch.vgic.in_kernel = true;
kvm->arch.vgic.vgic_model = type;
kvm->arch.vgic.vctrl_base = vgic->vctrl_base;
--
2.1.4
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