KVM: arm64: vgic-its: Implement ITS command queue command handlers
[linux-2.6-block.git] / virt / kvm / arm / vgic / vgic-its.c
index 4654d6edf6a6ded36e764743c633d40e26fcb008..1408c88d063e17ba64508c6484e7691cd5994d2f 100644 (file)
@@ -21,6 +21,8 @@
 #include <linux/kvm.h>
 #include <linux/kvm_host.h>
 #include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/uaccess.h>
 
 #include <linux/irqchip/arm-gic-v3.h>
 
 #include "vgic.h"
 #include "vgic-mmio.h"
 
+/*
+ * Creates a new (reference to a) struct vgic_irq for a given LPI.
+ * If this LPI is already mapped on another ITS, we increase its refcount
+ * and return a pointer to the existing structure.
+ * If this is a "new" LPI, we allocate and initialize a new struct vgic_irq.
+ * This function returns a pointer to the _unlocked_ structure.
+ */
+static struct vgic_irq *vgic_add_lpi(struct kvm *kvm, u32 intid)
+{
+       struct vgic_dist *dist = &kvm->arch.vgic;
+       struct vgic_irq *irq = vgic_get_irq(kvm, NULL, intid), *oldirq;
+
+       /* In this case there is no put, since we keep the reference. */
+       if (irq)
+               return irq;
+
+       irq = kzalloc(sizeof(struct vgic_irq), GFP_KERNEL);
+       if (!irq)
+               return NULL;
+
+       INIT_LIST_HEAD(&irq->lpi_list);
+       INIT_LIST_HEAD(&irq->ap_list);
+       spin_lock_init(&irq->irq_lock);
+
+       irq->config = VGIC_CONFIG_EDGE;
+       kref_init(&irq->refcount);
+       irq->intid = intid;
+
+       spin_lock(&dist->lpi_list_lock);
+
+       /*
+        * There could be a race with another vgic_add_lpi(), so we need to
+        * check that we don't add a second list entry with the same LPI.
+        */
+       list_for_each_entry(oldirq, &dist->lpi_list_head, lpi_list) {
+               if (oldirq->intid != intid)
+                       continue;
+
+               /* Someone was faster with adding this LPI, lets use that. */
+               kfree(irq);
+               irq = oldirq;
+
+               /*
+                * This increases the refcount, the caller is expected to
+                * call vgic_put_irq() on the returned pointer once it's
+                * finished with the IRQ.
+                */
+               kref_get(&irq->refcount);
+
+               goto out_unlock;
+       }
+
+       list_add_tail(&irq->lpi_list, &dist->lpi_list_head);
+       dist->lpi_list_count++;
+
+out_unlock:
+       spin_unlock(&dist->lpi_list_lock);
+
+       return irq;
+}
+
+struct its_device {
+       struct list_head dev_list;
+
+       /* the head for the list of ITTEs */
+       struct list_head itt_head;
+       u32 device_id;
+};
+
+#define COLLECTION_NOT_MAPPED ((u32)~0)
+
+struct its_collection {
+       struct list_head coll_list;
+
+       u32 collection_id;
+       u32 target_addr;
+};
+
+#define its_is_collection_mapped(coll) ((coll) && \
+                               ((coll)->target_addr != COLLECTION_NOT_MAPPED))
+
+struct its_itte {
+       struct list_head itte_list;
+
+       struct vgic_irq *irq;
+       struct its_collection *collection;
+       u32 lpi;
+       u32 event_id;
+};
+
+/*
+ * Find and returns a device in the device table for an ITS.
+ * Must be called with the its_lock mutex held.
+ */
+static struct its_device *find_its_device(struct vgic_its *its, u32 device_id)
+{
+       struct its_device *device;
+
+       list_for_each_entry(device, &its->device_list, dev_list)
+               if (device_id == device->device_id)
+                       return device;
+
+       return NULL;
+}
+
+/*
+ * Find and returns an interrupt translation table entry (ITTE) for a given
+ * Device ID/Event ID pair on an ITS.
+ * Must be called with the its_lock mutex held.
+ */
+static struct its_itte *find_itte(struct vgic_its *its, u32 device_id,
+                                 u32 event_id)
+{
+       struct its_device *device;
+       struct its_itte *itte;
+
+       device = find_its_device(its, device_id);
+       if (device == NULL)
+               return NULL;
+
+       list_for_each_entry(itte, &device->itt_head, itte_list)
+               if (itte->event_id == event_id)
+                       return itte;
+
+       return NULL;
+}
+
+/* To be used as an iterator this macro misses the enclosing parentheses */
+#define for_each_lpi_its(dev, itte, its) \
+       list_for_each_entry(dev, &(its)->device_list, dev_list) \
+               list_for_each_entry(itte, &(dev)->itt_head, itte_list)
+
+/*
+ * We only implement 48 bits of PA at the moment, although the ITS
+ * supports more. Let's be restrictive here.
+ */
+#define BASER_ADDRESS(x)       ((x) & GENMASK_ULL(47, 16))
+#define CBASER_ADDRESS(x)      ((x) & GENMASK_ULL(47, 12))
+#define PENDBASER_ADDRESS(x)   ((x) & GENMASK_ULL(47, 16))
+#define PROPBASER_ADDRESS(x)   ((x) & GENMASK_ULL(47, 12))
+
+#define GIC_LPI_OFFSET 8192
+
+/*
+ * Finds and returns a collection in the ITS collection table.
+ * Must be called with the its_lock mutex held.
+ */
+static struct its_collection *find_collection(struct vgic_its *its, int coll_id)
+{
+       struct its_collection *collection;
+
+       list_for_each_entry(collection, &its->collection_list, coll_list) {
+               if (coll_id == collection->collection_id)
+                       return collection;
+       }
+
+       return NULL;
+}
+
+#define LPI_PROP_ENABLE_BIT(p) ((p) & LPI_PROP_ENABLED)
+#define LPI_PROP_PRIORITY(p)   ((p) & 0xfc)
+
+/*
+ * Reads the configuration data for a given LPI from guest memory and
+ * updates the fields in struct vgic_irq.
+ * If filter_vcpu is not NULL, applies only if the IRQ is targeting this
+ * VCPU. Unconditionally applies if filter_vcpu is NULL.
+ */
+static int update_lpi_config(struct kvm *kvm, struct vgic_irq *irq,
+                            struct kvm_vcpu *filter_vcpu)
+{
+       u64 propbase = PROPBASER_ADDRESS(kvm->arch.vgic.propbaser);
+       u8 prop;
+       int ret;
+
+       ret = kvm_read_guest(kvm, propbase + irq->intid - GIC_LPI_OFFSET,
+                            &prop, 1);
+
+       if (ret)
+               return ret;
+
+       spin_lock(&irq->irq_lock);
+
+       if (!filter_vcpu || filter_vcpu == irq->target_vcpu) {
+               irq->priority = LPI_PROP_PRIORITY(prop);
+               irq->enabled = LPI_PROP_ENABLE_BIT(prop);
+
+               vgic_queue_irq_unlock(kvm, irq);
+       } else {
+               spin_unlock(&irq->irq_lock);
+       }
+
+       return 0;
+}
+
+/*
+ * Create a snapshot of the current LPI list, so that we can enumerate all
+ * LPIs without holding any lock.
+ * Returns the array length and puts the kmalloc'ed array into intid_ptr.
+ */
+static int vgic_copy_lpi_list(struct kvm *kvm, u32 **intid_ptr)
+{
+       struct vgic_dist *dist = &kvm->arch.vgic;
+       struct vgic_irq *irq;
+       u32 *intids;
+       int irq_count = dist->lpi_list_count, i = 0;
+
+       /*
+        * We use the current value of the list length, which may change
+        * after the kmalloc. We don't care, because the guest shouldn't
+        * change anything while the command handling is still running,
+        * and in the worst case we would miss a new IRQ, which one wouldn't
+        * expect to be covered by this command anyway.
+        */
+       intids = kmalloc_array(irq_count, sizeof(intids[0]), GFP_KERNEL);
+       if (!intids)
+               return -ENOMEM;
+
+       spin_lock(&dist->lpi_list_lock);
+       list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+               /* We don't need to "get" the IRQ, as we hold the list lock. */
+               intids[i] = irq->intid;
+               if (++i == irq_count)
+                       break;
+       }
+       spin_unlock(&dist->lpi_list_lock);
+
+       *intid_ptr = intids;
+       return irq_count;
+}
+
+/*
+ * Promotes the ITS view of affinity of an ITTE (which redistributor this LPI
+ * is targeting) to the VGIC's view, which deals with target VCPUs.
+ * Needs to be called whenever either the collection for a LPIs has
+ * changed or the collection itself got retargeted.
+ */
+static void update_affinity_itte(struct kvm *kvm, struct its_itte *itte)
+{
+       struct kvm_vcpu *vcpu;
+
+       if (!its_is_collection_mapped(itte->collection))
+               return;
+
+       vcpu = kvm_get_vcpu(kvm, itte->collection->target_addr);
+
+       spin_lock(&itte->irq->irq_lock);
+       itte->irq->target_vcpu = vcpu;
+       spin_unlock(&itte->irq->irq_lock);
+}
+
+/*
+ * Updates the target VCPU for every LPI targeting this collection.
+ * Must be called with the its_lock mutex held.
+ */
+static void update_affinity_collection(struct kvm *kvm, struct vgic_its *its,
+                                      struct its_collection *coll)
+{
+       struct its_device *device;
+       struct its_itte *itte;
+
+       for_each_lpi_its(device, itte, its) {
+               if (!itte->collection || coll != itte->collection)
+                       continue;
+
+               update_affinity_itte(kvm, itte);
+       }
+}
+
+static u32 max_lpis_propbaser(u64 propbaser)
+{
+       int nr_idbits = (propbaser & 0x1f) + 1;
+
+       return 1U << min(nr_idbits, INTERRUPT_ID_BITS_ITS);
+}
+
+/*
+ * Scan the whole LPI pending table and sync the pending bit in there
+ * with our own data structures. This relies on the LPI being
+ * mapped before.
+ */
+static int its_sync_lpi_pending_table(struct kvm_vcpu *vcpu)
+{
+       gpa_t pendbase = PENDBASER_ADDRESS(vcpu->arch.vgic_cpu.pendbaser);
+       struct vgic_irq *irq;
+       int last_byte_offset = -1;
+       int ret = 0;
+       u32 *intids;
+       int nr_irqs, i;
+
+       nr_irqs = vgic_copy_lpi_list(vcpu->kvm, &intids);
+       if (nr_irqs < 0)
+               return nr_irqs;
+
+       for (i = 0; i < nr_irqs; i++) {
+               int byte_offset, bit_nr;
+               u8 pendmask;
+
+               byte_offset = intids[i] / BITS_PER_BYTE;
+               bit_nr = intids[i] % BITS_PER_BYTE;
+
+               /*
+                * For contiguously allocated LPIs chances are we just read
+                * this very same byte in the last iteration. Reuse that.
+                */
+               if (byte_offset != last_byte_offset) {
+                       ret = kvm_read_guest(vcpu->kvm, pendbase + byte_offset,
+                                            &pendmask, 1);
+                       if (ret) {
+                               kfree(intids);
+                               return ret;
+                       }
+                       last_byte_offset = byte_offset;
+               }
+
+               irq = vgic_get_irq(vcpu->kvm, NULL, intids[i]);
+               spin_lock(&irq->irq_lock);
+               irq->pending = pendmask & (1U << bit_nr);
+               vgic_queue_irq_unlock(vcpu->kvm, irq);
+               vgic_put_irq(vcpu->kvm, irq);
+       }
+
+       kfree(intids);
+
+       return ret;
+}
+
+static unsigned long vgic_mmio_read_its_ctlr(struct kvm *vcpu,
+                                            struct vgic_its *its,
+                                            gpa_t addr, unsigned int len)
+{
+       u32 reg = 0;
+
+       mutex_lock(&its->cmd_lock);
+       if (its->creadr == its->cwriter)
+               reg |= GITS_CTLR_QUIESCENT;
+       if (its->enabled)
+               reg |= GITS_CTLR_ENABLE;
+       mutex_unlock(&its->cmd_lock);
+
+       return reg;
+}
+
+static void vgic_mmio_write_its_ctlr(struct kvm *kvm, struct vgic_its *its,
+                                    gpa_t addr, unsigned int len,
+                                    unsigned long val)
+{
+       its->enabled = !!(val & GITS_CTLR_ENABLE);
+}
+
+static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
+                                             struct vgic_its *its,
+                                             gpa_t addr, unsigned int len)
+{
+       u64 reg = GITS_TYPER_PLPIS;
+
+       /*
+        * We use linear CPU numbers for redistributor addressing,
+        * so GITS_TYPER.PTA is 0.
+        * Also we force all PROPBASER registers to be the same, so
+        * CommonLPIAff is 0 as well.
+        * To avoid memory waste in the guest, we keep the number of IDBits and
+        * DevBits low - as least for the time being.
+        */
+       reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
+       reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
+
+       return extract_bytes(reg, addr & 7, len);
+}
+
+static unsigned long vgic_mmio_read_its_iidr(struct kvm *kvm,
+                                            struct vgic_its *its,
+                                            gpa_t addr, unsigned int len)
+{
+       return (PRODUCT_ID_KVM << 24) | (IMPLEMENTER_ARM << 0);
+}
+
+static unsigned long vgic_mmio_read_its_idregs(struct kvm *kvm,
+                                              struct vgic_its *its,
+                                              gpa_t addr, unsigned int len)
+{
+       switch (addr & 0xffff) {
+       case GITS_PIDR0:
+               return 0x92;    /* part number, bits[7:0] */
+       case GITS_PIDR1:
+               return 0xb4;    /* part number, bits[11:8] */
+       case GITS_PIDR2:
+               return GIC_PIDR2_ARCH_GICv3 | 0x0b;
+       case GITS_PIDR4:
+               return 0x40;    /* This is a 64K software visible page */
+       /* The following are the ID registers for (any) GIC. */
+       case GITS_CIDR0:
+               return 0x0d;
+       case GITS_CIDR1:
+               return 0xf0;
+       case GITS_CIDR2:
+               return 0x05;
+       case GITS_CIDR3:
+               return 0xb1;
+       }
+
+       return 0;
+}
+
+/* Requires the its_lock to be held. */
+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);
+}
+
+static u64 its_cmd_mask_field(u64 *its_cmd, int word, int shift, int size)
+{
+       return (le64_to_cpu(its_cmd[word]) >> shift) & (BIT_ULL(size) - 1);
+}
+
+#define its_cmd_get_command(cmd)       its_cmd_mask_field(cmd, 0,  0,  8)
+#define its_cmd_get_deviceid(cmd)      its_cmd_mask_field(cmd, 0, 32, 32)
+#define its_cmd_get_id(cmd)            its_cmd_mask_field(cmd, 1,  0, 32)
+#define its_cmd_get_physical_id(cmd)   its_cmd_mask_field(cmd, 1, 32, 32)
+#define its_cmd_get_collection(cmd)    its_cmd_mask_field(cmd, 2,  0, 16)
+#define its_cmd_get_target_addr(cmd)   its_cmd_mask_field(cmd, 2, 16, 32)
+#define its_cmd_get_validbit(cmd)      its_cmd_mask_field(cmd, 2, 63,  1)
+
+/*
+ * The DISCARD command frees an Interrupt Translation Table Entry (ITTE).
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_discard(struct kvm *kvm, struct vgic_its *its,
+                                      u64 *its_cmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       u32 event_id = its_cmd_get_id(its_cmd);
+       struct its_itte *itte;
+
+
+       itte = find_itte(its, device_id, event_id);
+       if (itte && itte->collection) {
+               /*
+                * Though the spec talks about removing the pending state, we
+                * don't bother here since we clear the ITTE anyway and the
+                * pending state is a property of the ITTE struct.
+                */
+               its_free_itte(kvm, itte);
+               return 0;
+       }
+
+       return E_ITS_DISCARD_UNMAPPED_INTERRUPT;
+}
+
+/*
+ * The MOVI command moves an ITTE to a different collection.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its,
+                                   u64 *its_cmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       u32 event_id = its_cmd_get_id(its_cmd);
+       u32 coll_id = its_cmd_get_collection(its_cmd);
+       struct kvm_vcpu *vcpu;
+       struct its_itte *itte;
+       struct its_collection *collection;
+
+       itte = find_itte(its, device_id, event_id);
+       if (!itte)
+               return E_ITS_MOVI_UNMAPPED_INTERRUPT;
+
+       if (!its_is_collection_mapped(itte->collection))
+               return E_ITS_MOVI_UNMAPPED_COLLECTION;
+
+       collection = find_collection(its, coll_id);
+       if (!its_is_collection_mapped(collection))
+               return E_ITS_MOVI_UNMAPPED_COLLECTION;
+
+       itte->collection = collection;
+       vcpu = kvm_get_vcpu(kvm, collection->target_addr);
+
+       spin_lock(&itte->irq->irq_lock);
+       itte->irq->target_vcpu = vcpu;
+       spin_unlock(&itte->irq->irq_lock);
+
+       return 0;
+}
+
+static void vgic_its_init_collection(struct vgic_its *its,
+                                    struct its_collection *collection,
+                                    u32 coll_id)
+{
+       collection->collection_id = coll_id;
+       collection->target_addr = COLLECTION_NOT_MAPPED;
+
+       list_add_tail(&collection->coll_list, &its->collection_list);
+}
+
+/*
+ * The MAPTI and MAPI commands map LPIs to ITTEs.
+ * Must be called with its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_mapi(struct kvm *kvm, struct vgic_its *its,
+                                   u64 *its_cmd, u8 subcmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       u32 event_id = its_cmd_get_id(its_cmd);
+       u32 coll_id = its_cmd_get_collection(its_cmd);
+       struct its_itte *itte;
+       struct its_device *device;
+       struct its_collection *collection, *new_coll = NULL;
+       int lpi_nr;
+
+       device = find_its_device(its, device_id);
+       if (!device)
+               return E_ITS_MAPTI_UNMAPPED_DEVICE;
+
+       collection = find_collection(its, coll_id);
+       if (!collection) {
+               new_coll = kzalloc(sizeof(struct its_collection), GFP_KERNEL);
+               if (!new_coll)
+                       return -ENOMEM;
+       }
+
+       if (subcmd == GITS_CMD_MAPTI)
+               lpi_nr = its_cmd_get_physical_id(its_cmd);
+       else
+               lpi_nr = event_id;
+       if (lpi_nr < GIC_LPI_OFFSET ||
+           lpi_nr >= max_lpis_propbaser(kvm->arch.vgic.propbaser)) {
+               kfree(new_coll);
+               return E_ITS_MAPTI_PHYSICALID_OOR;
+       }
+
+       itte = find_itte(its, device_id, event_id);
+       if (!itte) {
+               itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
+               if (!itte) {
+                       kfree(new_coll);
+                       return -ENOMEM;
+               }
+
+               itte->event_id  = event_id;
+               list_add_tail(&itte->itte_list, &device->itt_head);
+       }
+
+       if (!collection) {
+               collection = new_coll;
+               vgic_its_init_collection(its, collection, coll_id);
+       }
+
+       itte->collection = collection;
+       itte->lpi = lpi_nr;
+       itte->irq = vgic_add_lpi(kvm, lpi_nr);
+       update_affinity_itte(kvm, itte);
+
+       /*
+        * We "cache" the configuration table entries in out struct vgic_irq's.
+        * However we only have those structs for mapped IRQs, so we read in
+        * the respective config data from memory here upon mapping the LPI.
+        */
+       update_lpi_config(kvm, itte->irq, NULL);
+
+       return 0;
+}
+
+/* Requires the its_lock to be held. */
+static void vgic_its_unmap_device(struct kvm *kvm, struct its_device *device)
+{
+       struct its_itte *itte, *temp;
+
+       /*
+        * The spec says that unmapping a device with still valid
+        * ITTEs associated is UNPREDICTABLE. We remove all ITTEs,
+        * since we cannot leave the memory unreferenced.
+        */
+       list_for_each_entry_safe(itte, temp, &device->itt_head, itte_list)
+               its_free_itte(kvm, itte);
+
+       list_del(&device->dev_list);
+       kfree(device);
+}
+
+/*
+ * Check whether a device ID can be stored into the guest device tables.
+ * For a direct table this is pretty easy, but gets a bit nasty for
+ * indirect tables. We check whether the resulting guest physical address
+ * is actually valid (covered by a memslot and guest accessbible).
+ * For this we have to read the respective first level entry.
+ */
+static bool vgic_its_check_device_id(struct kvm *kvm, struct vgic_its *its,
+                                    int device_id)
+{
+       u64 r = its->baser_device_table;
+       int nr_entries = GITS_BASER_NR_PAGES(r) * SZ_64K;
+       int index;
+       u64 indirect_ptr;
+       gfn_t gfn;
+
+
+       if (!(r & GITS_BASER_INDIRECT))
+               return device_id < (nr_entries / GITS_BASER_ENTRY_SIZE(r));
+
+       /* calculate and check the index into the 1st level */
+       index = device_id / (SZ_64K / GITS_BASER_ENTRY_SIZE(r));
+       if (index >= (nr_entries / sizeof(u64)))
+               return false;
+
+       /* Each 1st level entry is represented by a 64-bit value. */
+       if (!kvm_read_guest(kvm,
+                           BASER_ADDRESS(r) + index * sizeof(indirect_ptr),
+                           &indirect_ptr, sizeof(indirect_ptr)))
+               return false;
+
+       /* check the valid bit of the first level entry */
+       if (!(indirect_ptr & BIT_ULL(63)))
+               return false;
+
+       /*
+        * Mask the guest physical address and calculate the frame number.
+        * Any address beyond our supported 48 bits of PA will be caught
+        * by the actual check in the final step.
+        */
+       gfn = (indirect_ptr & GENMASK_ULL(51, 16)) >> PAGE_SHIFT;
+
+       return kvm_is_visible_gfn(kvm, gfn);
+}
+
+/*
+ * MAPD maps or unmaps a device ID to Interrupt Translation Tables (ITTs).
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_mapd(struct kvm *kvm, struct vgic_its *its,
+                                   u64 *its_cmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       bool valid = its_cmd_get_validbit(its_cmd);
+       struct its_device *device;
+
+       if (!vgic_its_check_device_id(kvm, its, device_id))
+               return E_ITS_MAPD_DEVICE_OOR;
+
+       device = find_its_device(its, device_id);
+
+       /*
+        * The spec says that calling MAPD on an already mapped device
+        * invalidates all cached data for this device. We implement this
+        * by removing the mapping and re-establishing it.
+        */
+       if (device)
+               vgic_its_unmap_device(kvm, device);
+
+       /*
+        * The spec does not say whether unmapping a not-mapped device
+        * is an error, so we are done in any case.
+        */
+       if (!valid)
+               return 0;
+
+       device = kzalloc(sizeof(struct its_device), GFP_KERNEL);
+       if (!device)
+               return -ENOMEM;
+
+       device->device_id = device_id;
+       INIT_LIST_HEAD(&device->itt_head);
+
+       list_add_tail(&device->dev_list, &its->device_list);
+
+       return 0;
+}
+
+static int vgic_its_nr_collection_ids(struct vgic_its *its)
+{
+       u64 r = its->baser_coll_table;
+
+       return (GITS_BASER_NR_PAGES(r) * SZ_64K) / GITS_BASER_ENTRY_SIZE(r);
+}
+
+/*
+ * The MAPC command maps collection IDs to redistributors.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_mapc(struct kvm *kvm, struct vgic_its *its,
+                                   u64 *its_cmd)
+{
+       u16 coll_id;
+       u32 target_addr;
+       struct its_collection *collection;
+       bool valid;
+
+       valid = its_cmd_get_validbit(its_cmd);
+       coll_id = its_cmd_get_collection(its_cmd);
+       target_addr = its_cmd_get_target_addr(its_cmd);
+
+       if (target_addr >= atomic_read(&kvm->online_vcpus))
+               return E_ITS_MAPC_PROCNUM_OOR;
+
+       if (coll_id >= vgic_its_nr_collection_ids(its))
+               return E_ITS_MAPC_COLLECTION_OOR;
+
+       collection = find_collection(its, coll_id);
+
+       if (!valid) {
+               struct its_device *device;
+               struct its_itte *itte;
+               /*
+                * Clearing the mapping for that collection ID removes the
+                * entry from the list. If there wasn't any before, we can
+                * go home early.
+                */
+               if (!collection)
+                       return 0;
+
+               for_each_lpi_its(device, itte, its)
+                       if (itte->collection &&
+                           itte->collection->collection_id == coll_id)
+                               itte->collection = NULL;
+
+               list_del(&collection->coll_list);
+               kfree(collection);
+       } else {
+               if (!collection) {
+                       collection = kzalloc(sizeof(struct its_collection),
+                                            GFP_KERNEL);
+                       if (!collection)
+                               return -ENOMEM;
+
+                       vgic_its_init_collection(its, collection, coll_id);
+                       collection->target_addr = target_addr;
+               } else {
+                       collection->target_addr = target_addr;
+                       update_affinity_collection(kvm, its, collection);
+               }
+       }
+
+       return 0;
+}
+
+/*
+ * The CLEAR command removes the pending state for a particular LPI.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_clear(struct kvm *kvm, struct vgic_its *its,
+                                    u64 *its_cmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       u32 event_id = its_cmd_get_id(its_cmd);
+       struct its_itte *itte;
+
+
+       itte = find_itte(its, device_id, event_id);
+       if (!itte)
+               return E_ITS_CLEAR_UNMAPPED_INTERRUPT;
+
+       itte->irq->pending = false;
+
+       return 0;
+}
+
+/*
+ * The INV command syncs the configuration bits from the memory table.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_inv(struct kvm *kvm, struct vgic_its *its,
+                                  u64 *its_cmd)
+{
+       u32 device_id = its_cmd_get_deviceid(its_cmd);
+       u32 event_id = its_cmd_get_id(its_cmd);
+       struct its_itte *itte;
+
+
+       itte = find_itte(its, device_id, event_id);
+       if (!itte)
+               return E_ITS_INV_UNMAPPED_INTERRUPT;
+
+       return update_lpi_config(kvm, itte->irq, NULL);
+}
+
+/*
+ * The INVALL command requests flushing of all IRQ data in this collection.
+ * Find the VCPU mapped to that collection, then iterate over the VM's list
+ * of mapped LPIs and update the configuration for each IRQ which targets
+ * the specified vcpu. The configuration will be read from the in-memory
+ * configuration table.
+ * Must be called with the its_lock mutex held.
+ */
+static int vgic_its_cmd_handle_invall(struct kvm *kvm, struct vgic_its *its,
+                                     u64 *its_cmd)
+{
+       u32 coll_id = its_cmd_get_collection(its_cmd);
+       struct its_collection *collection;
+       struct kvm_vcpu *vcpu;
+       struct vgic_irq *irq;
+       u32 *intids;
+       int irq_count, i;
+
+       collection = find_collection(its, coll_id);
+       if (!its_is_collection_mapped(collection))
+               return E_ITS_INVALL_UNMAPPED_COLLECTION;
+
+       vcpu = kvm_get_vcpu(kvm, collection->target_addr);
+
+       irq_count = vgic_copy_lpi_list(kvm, &intids);
+       if (irq_count < 0)
+               return irq_count;
+
+       for (i = 0; i < irq_count; i++) {
+               irq = vgic_get_irq(kvm, NULL, intids[i]);
+               if (!irq)
+                       continue;
+               update_lpi_config(kvm, irq, vcpu);
+               vgic_put_irq(kvm, irq);
+       }
+
+       kfree(intids);
+
+       return 0;
+}
+
+/*
+ * The MOVALL command moves the pending state of all IRQs targeting one
+ * redistributor to another. We don't hold the pending state in the VCPUs,
+ * but in the IRQs instead, so there is really not much to do for us here.
+ * However the spec says that no IRQ must target the old redistributor
+ * afterwards, so we make sure that no LPI is using the associated target_vcpu.
+ * This command affects all LPIs in the system that target that redistributor.
+ */
+static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its,
+                                     u64 *its_cmd)
+{
+       struct vgic_dist *dist = &kvm->arch.vgic;
+       u32 target1_addr = its_cmd_get_target_addr(its_cmd);
+       u32 target2_addr = its_cmd_mask_field(its_cmd, 3, 16, 32);
+       struct kvm_vcpu *vcpu1, *vcpu2;
+       struct vgic_irq *irq;
+
+       if (target1_addr >= atomic_read(&kvm->online_vcpus) ||
+           target2_addr >= atomic_read(&kvm->online_vcpus))
+               return E_ITS_MOVALL_PROCNUM_OOR;
+
+       if (target1_addr == target2_addr)
+               return 0;
+
+       vcpu1 = kvm_get_vcpu(kvm, target1_addr);
+       vcpu2 = kvm_get_vcpu(kvm, target2_addr);
+
+       spin_lock(&dist->lpi_list_lock);
+
+       list_for_each_entry(irq, &dist->lpi_list_head, lpi_list) {
+               spin_lock(&irq->irq_lock);
+
+               if (irq->target_vcpu == vcpu1)
+                       irq->target_vcpu = vcpu2;
+
+               spin_unlock(&irq->irq_lock);
+       }
+
+       spin_unlock(&dist->lpi_list_lock);
+
+       return 0;
+}
+
+/*
+ * This function is called with the its_cmd lock held, but the ITS data
+ * structure lock dropped.
+ */
+static int vgic_its_handle_command(struct kvm *kvm, struct vgic_its *its,
+                                  u64 *its_cmd)
+{
+       u8 cmd = its_cmd_get_command(its_cmd);
+       int ret = -ENODEV;
+
+       mutex_lock(&its->its_lock);
+       switch (cmd) {
+       case GITS_CMD_MAPD:
+               ret = vgic_its_cmd_handle_mapd(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_MAPC:
+               ret = vgic_its_cmd_handle_mapc(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_MAPI:
+               ret = vgic_its_cmd_handle_mapi(kvm, its, its_cmd, cmd);
+               break;
+       case GITS_CMD_MAPTI:
+               ret = vgic_its_cmd_handle_mapi(kvm, its, its_cmd, cmd);
+               break;
+       case GITS_CMD_MOVI:
+               ret = vgic_its_cmd_handle_movi(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_DISCARD:
+               ret = vgic_its_cmd_handle_discard(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_CLEAR:
+               ret = vgic_its_cmd_handle_clear(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_MOVALL:
+               ret = vgic_its_cmd_handle_movall(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_INV:
+               ret = vgic_its_cmd_handle_inv(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_INVALL:
+               ret = vgic_its_cmd_handle_invall(kvm, its, its_cmd);
+               break;
+       case GITS_CMD_SYNC:
+               /* we ignore this command: we are in sync all of the time */
+               ret = 0;
+               break;
+       }
+       mutex_unlock(&its->its_lock);
+
+       return ret;
+}
+
+static u64 vgic_sanitise_its_baser(u64 reg)
+{
+       reg = vgic_sanitise_field(reg, GITS_BASER_SHAREABILITY_MASK,
+                                 GITS_BASER_SHAREABILITY_SHIFT,
+                                 vgic_sanitise_shareability);
+       reg = vgic_sanitise_field(reg, GITS_BASER_INNER_CACHEABILITY_MASK,
+                                 GITS_BASER_INNER_CACHEABILITY_SHIFT,
+                                 vgic_sanitise_inner_cacheability);
+       reg = vgic_sanitise_field(reg, GITS_BASER_OUTER_CACHEABILITY_MASK,
+                                 GITS_BASER_OUTER_CACHEABILITY_SHIFT,
+                                 vgic_sanitise_outer_cacheability);
+
+       /* Bits 15:12 contain bits 51:48 of the PA, which we don't support. */
+       reg &= ~GENMASK_ULL(15, 12);
+
+       /* We support only one (ITS) page size: 64K */
+       reg = (reg & ~GITS_BASER_PAGE_SIZE_MASK) | GITS_BASER_PAGE_SIZE_64K;
+
+       return reg;
+}
+
+static u64 vgic_sanitise_its_cbaser(u64 reg)
+{
+       reg = vgic_sanitise_field(reg, GITS_CBASER_SHAREABILITY_MASK,
+                                 GITS_CBASER_SHAREABILITY_SHIFT,
+                                 vgic_sanitise_shareability);
+       reg = vgic_sanitise_field(reg, GITS_CBASER_INNER_CACHEABILITY_MASK,
+                                 GITS_CBASER_INNER_CACHEABILITY_SHIFT,
+                                 vgic_sanitise_inner_cacheability);
+       reg = vgic_sanitise_field(reg, GITS_CBASER_OUTER_CACHEABILITY_MASK,
+                                 GITS_CBASER_OUTER_CACHEABILITY_SHIFT,
+                                 vgic_sanitise_outer_cacheability);
+
+       /*
+        * Sanitise the physical address to be 64k aligned.
+        * Also limit the physical addresses to 48 bits.
+        */
+       reg &= ~(GENMASK_ULL(51, 48) | GENMASK_ULL(15, 12));
+
+       return reg;
+}
+
+static unsigned long vgic_mmio_read_its_cbaser(struct kvm *kvm,
+                                              struct vgic_its *its,
+                                              gpa_t addr, unsigned int len)
+{
+       return extract_bytes(its->cbaser, addr & 7, len);
+}
+
+static void vgic_mmio_write_its_cbaser(struct kvm *kvm, struct vgic_its *its,
+                                      gpa_t addr, unsigned int len,
+                                      unsigned long val)
+{
+       /* When GITS_CTLR.Enable is 1, this register is RO. */
+       if (its->enabled)
+               return;
+
+       mutex_lock(&its->cmd_lock);
+       its->cbaser = update_64bit_reg(its->cbaser, addr & 7, len, val);
+       its->cbaser = vgic_sanitise_its_cbaser(its->cbaser);
+       its->creadr = 0;
+       /*
+        * CWRITER is architecturally UNKNOWN on reset, but we need to reset
+        * it to CREADR to make sure we start with an empty command buffer.
+        */
+       its->cwriter = its->creadr;
+       mutex_unlock(&its->cmd_lock);
+}
+
+#define ITS_CMD_BUFFER_SIZE(baser)     ((((baser) & 0xff) + 1) << 12)
+#define ITS_CMD_SIZE                   32
+#define ITS_CMD_OFFSET(reg)            ((reg) & GENMASK(19, 5))
+
+/*
+ * By writing to CWRITER the guest announces new commands to be processed.
+ * To avoid any races in the first place, we take the its_cmd lock, which
+ * protects our ring buffer variables, so that there is only one user
+ * per ITS handling commands at a given time.
+ */
+static void vgic_mmio_write_its_cwriter(struct kvm *kvm, struct vgic_its *its,
+                                       gpa_t addr, unsigned int len,
+                                       unsigned long val)
+{
+       gpa_t cbaser;
+       u64 cmd_buf[4];
+       u32 reg;
+
+       if (!its)
+               return;
+
+       mutex_lock(&its->cmd_lock);
+
+       reg = update_64bit_reg(its->cwriter, addr & 7, len, val);
+       reg = ITS_CMD_OFFSET(reg);
+       if (reg >= ITS_CMD_BUFFER_SIZE(its->cbaser)) {
+               mutex_unlock(&its->cmd_lock);
+               return;
+       }
+
+       its->cwriter = reg;
+       cbaser = CBASER_ADDRESS(its->cbaser);
+
+       while (its->cwriter != its->creadr) {
+               int ret = kvm_read_guest(kvm, cbaser + its->creadr,
+                                        cmd_buf, ITS_CMD_SIZE);
+               /*
+                * If kvm_read_guest() fails, this could be due to the guest
+                * programming a bogus value in CBASER or something else going
+                * wrong from which we cannot easily recover.
+                * According to section 6.3.2 in the GICv3 spec we can just
+                * ignore that command then.
+                */
+               if (!ret)
+                       vgic_its_handle_command(kvm, its, cmd_buf);
+
+               its->creadr += ITS_CMD_SIZE;
+               if (its->creadr == ITS_CMD_BUFFER_SIZE(its->cbaser))
+                       its->creadr = 0;
+       }
+
+       mutex_unlock(&its->cmd_lock);
+}
+
+static unsigned long vgic_mmio_read_its_cwriter(struct kvm *kvm,
+                                               struct vgic_its *its,
+                                               gpa_t addr, unsigned int len)
+{
+       return extract_bytes(its->cwriter, addr & 0x7, len);
+}
+
+static unsigned long vgic_mmio_read_its_creadr(struct kvm *kvm,
+                                              struct vgic_its *its,
+                                              gpa_t addr, unsigned int len)
+{
+       return extract_bytes(its->creadr, addr & 0x7, len);
+}
+
+#define BASER_INDEX(addr) (((addr) / sizeof(u64)) & 0x7)
+static unsigned long vgic_mmio_read_its_baser(struct kvm *kvm,
+                                             struct vgic_its *its,
+                                             gpa_t addr, unsigned int len)
+{
+       u64 reg;
+
+       switch (BASER_INDEX(addr)) {
+       case 0:
+               reg = its->baser_device_table;
+               break;
+       case 1:
+               reg = its->baser_coll_table;
+               break;
+       default:
+               reg = 0;
+               break;
+       }
+
+       return extract_bytes(reg, addr & 7, len);
+}
+
+#define GITS_BASER_RO_MASK     (GENMASK_ULL(52, 48) | GENMASK_ULL(58, 56))
+static void vgic_mmio_write_its_baser(struct kvm *kvm,
+                                     struct vgic_its *its,
+                                     gpa_t addr, unsigned int len,
+                                     unsigned long val)
+{
+       u64 entry_size, device_type;
+       u64 reg, *regptr, clearbits = 0;
+
+       /* When GITS_CTLR.Enable is 1, we ignore write accesses. */
+       if (its->enabled)
+               return;
+
+       switch (BASER_INDEX(addr)) {
+       case 0:
+               regptr = &its->baser_device_table;
+               entry_size = 8;
+               device_type = GITS_BASER_TYPE_DEVICE;
+               break;
+       case 1:
+               regptr = &its->baser_coll_table;
+               entry_size = 8;
+               device_type = GITS_BASER_TYPE_COLLECTION;
+               clearbits = GITS_BASER_INDIRECT;
+               break;
+       default:
+               return;
+       }
+
+       reg = update_64bit_reg(*regptr, addr & 7, len, val);
+       reg &= ~GITS_BASER_RO_MASK;
+       reg &= ~clearbits;
+
+       reg |= (entry_size - 1) << GITS_BASER_ENTRY_SIZE_SHIFT;
+       reg |= device_type << GITS_BASER_TYPE_SHIFT;
+       reg = vgic_sanitise_its_baser(reg);
+
+       *regptr = reg;
+}
+
 #define REGISTER_ITS_DESC(off, rd, wr, length, acc)            \
 {                                                              \
        .reg_offset = off,                                      \
        .its_write = wr,                                        \
 }
 
-static unsigned long its_mmio_read_raz(struct kvm *kvm, struct vgic_its *its,
-                                      gpa_t addr, unsigned int len)
-{
-       return 0;
-}
-
 static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
                              gpa_t addr, unsigned int len, unsigned long val)
 {
@@ -54,36 +1164,46 @@ static void its_mmio_write_wi(struct kvm *kvm, struct vgic_its *its,
 
 static struct vgic_register_region its_registers[] = {
        REGISTER_ITS_DESC(GITS_CTLR,
-               its_mmio_read_raz, its_mmio_write_wi, 4,
+               vgic_mmio_read_its_ctlr, vgic_mmio_write_its_ctlr, 4,
                VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_IIDR,
-               its_mmio_read_raz, its_mmio_write_wi, 4,
+               vgic_mmio_read_its_iidr, its_mmio_write_wi, 4,
                VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_TYPER,
-               its_mmio_read_raz, its_mmio_write_wi, 8,
+               vgic_mmio_read_its_typer, its_mmio_write_wi, 8,
                VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_CBASER,
-               its_mmio_read_raz, its_mmio_write_wi, 8,
+               vgic_mmio_read_its_cbaser, vgic_mmio_write_its_cbaser, 8,
                VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_CWRITER,
-               its_mmio_read_raz, its_mmio_write_wi, 8,
+               vgic_mmio_read_its_cwriter, vgic_mmio_write_its_cwriter, 8,
                VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_CREADR,
-               its_mmio_read_raz, its_mmio_write_wi, 8,
+               vgic_mmio_read_its_creadr, its_mmio_write_wi, 8,
                VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_BASER,
-               its_mmio_read_raz, its_mmio_write_wi, 0x40,
+               vgic_mmio_read_its_baser, vgic_mmio_write_its_baser, 0x40,
                VGIC_ACCESS_64bit | VGIC_ACCESS_32bit),
        REGISTER_ITS_DESC(GITS_IDREGS_BASE,
-               its_mmio_read_raz, its_mmio_write_wi, 0x30,
+               vgic_mmio_read_its_idregs, its_mmio_write_wi, 0x30,
                VGIC_ACCESS_32bit),
 };
 
+/* This is called on setting the LPI enable bit in the redistributor. */
+void vgic_enable_lpis(struct kvm_vcpu *vcpu)
+{
+       if (!(vcpu->arch.vgic_cpu.pendbaser & GICR_PENDBASER_PTZ))
+               its_sync_lpi_pending_table(vcpu);
+}
+
 static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
 {
        struct vgic_io_device *iodev = &its->iodev;
        int ret;
 
+       if (its->initialized)
+               return 0;
+
        if (IS_VGIC_ADDR_UNDEF(its->vgic_its_base))
                return -ENXIO;
 
@@ -99,5 +1219,189 @@ static int vgic_its_init_its(struct kvm *kvm, struct vgic_its *its)
                                      KVM_VGIC_V3_ITS_SIZE, &iodev->dev);
        mutex_unlock(&kvm->slots_lock);
 
+       if (!ret)
+               its->initialized = true;
+
        return ret;
 }
+
+#define INITIAL_BASER_VALUE                                              \
+       (GIC_BASER_CACHEABILITY(GITS_BASER, INNER, RaWb)                | \
+        GIC_BASER_CACHEABILITY(GITS_BASER, OUTER, SameAsInner)         | \
+        GIC_BASER_SHAREABILITY(GITS_BASER, InnerShareable)             | \
+        ((8ULL - 1) << GITS_BASER_ENTRY_SIZE_SHIFT)                    | \
+        GITS_BASER_PAGE_SIZE_64K)
+
+#define INITIAL_PROPBASER_VALUE                                                  \
+       (GIC_BASER_CACHEABILITY(GICR_PROPBASER, INNER, RaWb)            | \
+        GIC_BASER_CACHEABILITY(GICR_PROPBASER, OUTER, SameAsInner)     | \
+        GIC_BASER_SHAREABILITY(GICR_PROPBASER, InnerShareable))
+
+static int vgic_its_create(struct kvm_device *dev, u32 type)
+{
+       struct vgic_its *its;
+
+       if (type != KVM_DEV_TYPE_ARM_VGIC_ITS)
+               return -ENODEV;
+
+       its = kzalloc(sizeof(struct vgic_its), GFP_KERNEL);
+       if (!its)
+               return -ENOMEM;
+
+       mutex_init(&its->its_lock);
+       mutex_init(&its->cmd_lock);
+
+       its->vgic_its_base = VGIC_ADDR_UNDEF;
+
+       INIT_LIST_HEAD(&its->device_list);
+       INIT_LIST_HEAD(&its->collection_list);
+
+       dev->kvm->arch.vgic.has_its = true;
+       its->initialized = false;
+       its->enabled = false;
+
+       its->baser_device_table = INITIAL_BASER_VALUE                   |
+               ((u64)GITS_BASER_TYPE_DEVICE << GITS_BASER_TYPE_SHIFT);
+       its->baser_coll_table = INITIAL_BASER_VALUE |
+               ((u64)GITS_BASER_TYPE_COLLECTION << GITS_BASER_TYPE_SHIFT);
+       dev->kvm->arch.vgic.propbaser = INITIAL_PROPBASER_VALUE;
+
+       dev->private = its;
+
+       return 0;
+}
+
+static void vgic_its_destroy(struct kvm_device *kvm_dev)
+{
+       struct kvm *kvm = kvm_dev->kvm;
+       struct vgic_its *its = kvm_dev->private;
+       struct its_device *dev;
+       struct its_itte *itte;
+       struct list_head *dev_cur, *dev_temp;
+       struct list_head *cur, *temp;
+
+       /*
+        * We may end up here without the lists ever having been initialized.
+        * Check this and bail out early to avoid dereferencing a NULL pointer.
+        */
+       if (!its->device_list.next)
+               return;
+
+       mutex_lock(&its->its_lock);
+       list_for_each_safe(dev_cur, dev_temp, &its->device_list) {
+               dev = container_of(dev_cur, struct its_device, dev_list);
+               list_for_each_safe(cur, temp, &dev->itt_head) {
+                       itte = (container_of(cur, struct its_itte, itte_list));
+                       its_free_itte(kvm, itte);
+               }
+               list_del(dev_cur);
+               kfree(dev);
+       }
+
+       list_for_each_safe(cur, temp, &its->collection_list) {
+               list_del(cur);
+               kfree(container_of(cur, struct its_collection, coll_list));
+       }
+       mutex_unlock(&its->its_lock);
+
+       kfree(its);
+}
+
+static int vgic_its_has_attr(struct kvm_device *dev,
+                            struct kvm_device_attr *attr)
+{
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_ADDR:
+               switch (attr->attr) {
+               case KVM_VGIC_ITS_ADDR_TYPE:
+                       return 0;
+               }
+               break;
+       case KVM_DEV_ARM_VGIC_GRP_CTRL:
+               switch (attr->attr) {
+               case KVM_DEV_ARM_VGIC_CTRL_INIT:
+                       return 0;
+               }
+               break;
+       }
+       return -ENXIO;
+}
+
+static int vgic_its_set_attr(struct kvm_device *dev,
+                            struct kvm_device_attr *attr)
+{
+       struct vgic_its *its = dev->private;
+       int ret;
+
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+               u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+               unsigned long type = (unsigned long)attr->attr;
+               u64 addr;
+
+               if (type != KVM_VGIC_ITS_ADDR_TYPE)
+                       return -ENODEV;
+
+               if (its->initialized)
+                       return -EBUSY;
+
+               if (copy_from_user(&addr, uaddr, sizeof(addr)))
+                       return -EFAULT;
+
+               ret = vgic_check_ioaddr(dev->kvm, &its->vgic_its_base,
+                                       addr, SZ_64K);
+               if (ret)
+                       return ret;
+
+               its->vgic_its_base = addr;
+
+               return 0;
+       }
+       case KVM_DEV_ARM_VGIC_GRP_CTRL:
+               switch (attr->attr) {
+               case KVM_DEV_ARM_VGIC_CTRL_INIT:
+                       return vgic_its_init_its(dev->kvm, its);
+               }
+               break;
+       }
+       return -ENXIO;
+}
+
+static int vgic_its_get_attr(struct kvm_device *dev,
+                            struct kvm_device_attr *attr)
+{
+       switch (attr->group) {
+       case KVM_DEV_ARM_VGIC_GRP_ADDR: {
+               struct vgic_its *its = dev->private;
+               u64 addr = its->vgic_its_base;
+               u64 __user *uaddr = (u64 __user *)(long)attr->addr;
+               unsigned long type = (unsigned long)attr->attr;
+
+               if (type != KVM_VGIC_ITS_ADDR_TYPE)
+                       return -ENODEV;
+
+               if (copy_to_user(uaddr, &addr, sizeof(addr)))
+                       return -EFAULT;
+               break;
+       default:
+               return -ENXIO;
+       }
+       }
+
+       return 0;
+}
+
+static struct kvm_device_ops kvm_arm_vgic_its_ops = {
+       .name = "kvm-arm-vgic-its",
+       .create = vgic_its_create,
+       .destroy = vgic_its_destroy,
+       .set_attr = vgic_its_set_attr,
+       .get_attr = vgic_its_get_attr,
+       .has_attr = vgic_its_has_attr,
+};
+
+int kvm_vgic_register_its_device(void)
+{
+       return kvm_register_device_ops(&kvm_arm_vgic_its_ops,
+                                      KVM_DEV_TYPE_ARM_VGIC_ITS);
+}