1 files changed, 92 insertions, 0 deletions

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 737ba3c9e9be..d5c0057196ae 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -244,6 +244,8 @@ static struct its_ite *find_ite(struct vgic_its *its, u32 device_id,
 
 #define VITS_TYPER_IDBITS 16
 #define VITS_TYPER_DEVBITS 16
+#define VITS_DTE_MAX_DEVID_OFFSET       (BIT(14) - 1)
+#define VITS_ITE_MAX_EVENTID_OFFSET     (BIT(16) - 1)
 
 /*
  * Finds and returns a collection in the ITS collection table.
@@ -1728,6 +1730,96 @@ out:
         return ret;
 }
 
+u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev)
+{
+        struct its_device *next;
+        u32 next_offset;
+
+        if (list_is_last(&dev->dev_list, h))
+                return 0;
+        next = list_next_entry(dev, dev_list);
+        next_offset = next->device_id - dev->device_id;
+
+        return min_t(u32, next_offset, VITS_DTE_MAX_DEVID_OFFSET);
+}
+
+u32 compute_next_eventid_offset(struct list_head *h, struct its_ite *ite)
+{
+        struct its_ite *next;
+        u32 next_offset;
+
+        if (list_is_last(&ite->ite_list, h))
+                return 0;
+        next = list_next_entry(ite, ite_list);
+        next_offset = next->event_id - ite->event_id;
+
+        return min_t(u32, next_offset, VITS_ITE_MAX_EVENTID_OFFSET);
+}
+
+/**
+ * entry_fn_t - Callback called on a table entry restore path
+ * @its: its handle
+ * @id: id of the entry
+ * @entry: pointer to the entry
+ * @opaque: pointer to an opaque data
+ *
+ * Return: < 0 on error, 0 if last element was identified, id offset to next
+ * element otherwise
+ */
+typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *entry,
+                          void *opaque);
+
+/**
+ * scan_its_table - Scan a contiguous table in guest RAM and applies a function
+ * to each entry
+ *
+ * @its: its handle
+ * @base: base gpa of the table
+ * @size: size of the table in bytes
+ * @esz: entry size in bytes
+ * @start_id: the ID of the first entry in the table
+ * (non zero for 2d level tables)
+ * @fn: function to apply on each entry
+ *
+ * Return: < 0 on error, 0 if last element was identified, 1 otherwise
+ * (the last element may not be found on second level tables)
+ */
+int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,
+                   int start_id, entry_fn_t fn, void *opaque)
+{
+        void *entry = kzalloc(esz, GFP_KERNEL);
+        struct kvm *kvm = its->dev->kvm;
+        unsigned long len = size;
+        int id = start_id;
+        gpa_t gpa = base;
+        int ret;
+
+        while (len > 0) {
+                int next_offset;
+                size_t byte_offset;
+
+                ret = kvm_read_guest(kvm, gpa, entry, esz);
+                if (ret)
+                        goto out;
+
+                next_offset = fn(its, id, entry, opaque);
+                if (next_offset <= 0) {
+                        ret = next_offset;
+                        goto out;
+                }
+
+                byte_offset = next_offset * esz;
+                id += next_offset;
+                gpa += byte_offset;
+                len -= byte_offset;
+        }
+        ret =  1;
+
+out:
+        kfree(entry);
+        return ret;
+}
+
 /**
  * vgic_its_save_device_tables - Save the device table and all ITT
  * into guest RAM