This patch saves the device table entries into guest RAM.
Both flat table and 2 stage tables are supported. DeviceId
indexing is used.

For each device listed in the device table, we also save
the translation table using the vgic_its_save/restore_itt
routines.

On restore, devices are re-allocated and their ite are
re-built.

Signed-off-by: Eric Auger <[email protected]>

---
v4 -> v5:
- sort the device list by deviceid on device table save
- use defines for shifts and masks
- use abi->dte_esz
- clatify entry sizes for L1 and L2 tables

v3 -> v4:
- use the new proto for its_alloc_device
- compute_next_devid_offset, vgic_its_flush/restore_itt
  become static in this patch
- change in the DTE entry format with the introduction of the
  valid bit and next field width decrease; ittaddr encoded
  on its full range
- fix handle_l1_entry entry handling
- correct vgic_its_table_restore error handling

v2 -> v3:
- fix itt_addr bitmask in vgic_its_restore_dte
- addition of return 0 in vgic_its_restore_ite moved to
  the ITE related patch

v1 -> v2:
- use 8 byte format for DTE and ITE
- support 2 stage format
- remove kvm parameter
- ITT flush/restore moved in a separate patch
- use deviceid indexing
---
 virt/kvm/arm/vgic/vgic-its.c | 183 +++++++++++++++++++++++++++++++++++++++++--
 virt/kvm/arm/vgic/vgic.h     |   7 ++
 2 files changed, 185 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index b02fc3f..86dfc6c 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -1682,7 +1682,8 @@ int vgic_its_attr_regs_access(struct kvm_device *dev,
        return ret;
 }
 
-u32 compute_next_devid_offset(struct list_head *h, struct its_device *dev)
+static u32 compute_next_devid_offset(struct list_head *h,
+                                    struct its_device *dev)
 {
        struct list_head *e = &dev->dev_list;
        struct its_device *next;
@@ -1858,7 +1859,7 @@ static int vgic_its_ite_cmp(void *priv, struct list_head 
*a,
                return 1;
 }
 
-int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
+static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
 {
        const struct vgic_its_abi *abi = vgic_its_get_abi(its);
        gpa_t base = device->itt_addr;
@@ -1877,7 +1878,7 @@ int vgic_its_save_itt(struct vgic_its *its, struct 
its_device *device)
        return 0;
 }
 
-int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
+static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
 {
        const struct vgic_its_abi *abi = vgic_its_get_abi(its);
        gpa_t base = dev->itt_addr;
@@ -1895,12 +1896,161 @@ int vgic_its_restore_itt(struct vgic_its *its, struct 
its_device *dev)
 }
 
 /**
+ * vgic_its_save_dte - Save a device table entry at a given GPA
+ *
+ * @its: ITS handle
+ * @dev: ITS device
+ * @ptr: GPA
+ */
+static int vgic_its_save_dte(struct vgic_its *its, struct its_device *dev,
+                            gpa_t ptr, int dte_esz)
+{
+       struct kvm *kvm = its->dev->kvm;
+       u64 val, itt_addr_field;
+       int ret;
+       u32 next_offset;
+
+       itt_addr_field = dev->itt_addr >> 8;
+       next_offset = compute_next_devid_offset(&its->device_list, dev);
+       val = (1ULL << KVM_ITS_DTE_VALID_SHIFT |
+              ((u64)next_offset << KVM_ITS_DTE_NEXT_SHIFT) |
+              (itt_addr_field << KVM_ITS_DTE_ITTADDR_SHIFT) |
+               (dev->nb_eventid_bits - 1));
+       val = cpu_to_le64(val);
+       ret = kvm_write_guest(kvm, ptr, &val, dte_esz);
+       return ret;
+}
+
+/**
+ * vgic_its_restore_dte - restore a device table entry
+ *
+ * @its: its handle
+ * @id: device id the DTE corresponds to
+ * @ptr: kernel VA where the 8 byte DTE is located
+ * @opaque: unused
+ * @next: offset to the next valid device id
+ *
+ * Return: < 0 on error, 0 otherwise
+ */
+static int vgic_its_restore_dte(struct vgic_its *its, u32 id,
+                               void *ptr, void *opaque, u32 *next)
+{
+       struct its_device *dev;
+       gpa_t itt_addr;
+       u8 nb_eventid_bits;
+       u64 entry = *(u64 *)ptr;
+       bool valid;
+       int ret;
+
+       entry = le64_to_cpu(entry);
+
+       valid = entry >> KVM_ITS_DTE_VALID_SHIFT;
+       nb_eventid_bits = (entry & KVM_ITS_DTE_SIZE_MASK) + 1;
+       itt_addr = ((entry & KVM_ITS_DTE_ITTADDR_MASK)
+                       >> KVM_ITS_DTE_ITTADDR_SHIFT) << 8;
+       *next = 1;
+
+       if (!valid)
+               return 0;
+
+       /* dte entry is valid */
+       *next = (entry & KVM_ITS_DTE_NEXT_MASK) >> KVM_ITS_DTE_NEXT_SHIFT;
+
+       ret = vgic_its_alloc_device(its, &dev, id,
+                                   itt_addr, nb_eventid_bits);
+       if (ret)
+               return ret;
+       ret = vgic_its_restore_itt(its, dev);
+
+       return ret;
+}
+
+static int vgic_its_device_cmp(void *priv, struct list_head *a,
+                              struct list_head *b)
+{
+       struct its_device *deva = container_of(a, struct its_device, dev_list);
+       struct its_device *devb = container_of(b, struct its_device, dev_list);
+
+       if (deva->device_id < devb->device_id)
+               return -1;
+       else
+               return 1;
+}
+
+/**
  * vgic_its_save_device_tables - Save the device table and all ITT
  * into guest RAM
+ *
+ * L1/L2 handling is hidden by vgic_its_check_id() helper which directly
+ * returns the GPA of the device entry
  */
 static int vgic_its_save_device_tables(struct vgic_its *its)
 {
-       return -ENXIO;
+       const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+       struct its_device *dev;
+       int dte_esz = abi->dte_esz;
+       u64 baser;
+
+       baser = its->baser_device_table;
+
+       list_sort(NULL, &its->device_list, vgic_its_device_cmp);
+
+       list_for_each_entry(dev, &its->device_list, dev_list) {
+               int ret;
+               gpa_t eaddr;
+
+               if (!vgic_its_check_id(its, baser,
+                                      dev->device_id, &eaddr))
+                       return -EINVAL;
+
+               ret = vgic_its_save_itt(its, dev);
+               if (ret)
+                       return ret;
+
+               ret = vgic_its_save_dte(its, dev, eaddr, dte_esz);
+               if (ret)
+                       return ret;
+       }
+       return 0;
+}
+
+/**
+ * handle_l1_entry - callback used for L1 entries (2 stage case)
+ *
+ * @its: its handle
+ * @id: id
+ * @addr: kernel VA
+ * @opaque: unused
+ * @next_offset: offset to the next L1 entry: 0 if the last element
+ * was found, 1 otherwise
+ */
+static int handle_l1_entry(struct vgic_its *its, u32 id, void *addr,
+                          void *opaque, u32 *next_offset)
+{
+       const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+       int l2_start_id = id * (SZ_64K / GITS_LVL1_ENTRY_SIZE);
+       u64 entry = *(u64 *)addr;
+       int ret, ite_esz = abi->ite_esz;
+       gpa_t gpa;
+
+       entry = le64_to_cpu(entry);
+       *next_offset = 1;
+
+       if (!(entry & BIT_ULL(63)))
+               return 0;
+
+       gpa = entry & GENMASK_ULL(51, 16);
+
+       ret = lookup_table(its, gpa, SZ_64K, ite_esz,
+                          l2_start_id, vgic_its_restore_dte, NULL);
+
+       if (ret == 1) {
+               /* last entry was found in this L2 table */
+               *next_offset = 0;
+               ret = 0;
+       }
+
+       return ret;
 }
 
 /**
@@ -1909,7 +2059,30 @@ static int vgic_its_save_device_tables(struct vgic_its 
*its)
  */
 static int vgic_its_restore_device_tables(struct vgic_its *its)
 {
-       return -ENXIO;
+       const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+       u64 baser = its->baser_device_table;
+       int l1_esz, ret, l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
+       gpa_t l1_gpa;
+
+       l1_gpa = BASER_ADDRESS(baser);
+       if (!l1_gpa)
+               return 0;
+
+       if (baser & GITS_BASER_INDIRECT) {
+               l1_esz = 8;
+               ret = lookup_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,
+                                  handle_l1_entry, NULL);
+       } else {
+               l1_esz = abi->dte_esz;
+               ret = lookup_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,
+                                  vgic_its_restore_dte, NULL);
+       }
+
+       if (ret < 0)
+               return ret;
+
+       /* if last element was not found we have an issue here */
+       return ret ? 0 : -EINVAL;
 }
 
 static int vgic_its_save_cte(struct vgic_its *its,
diff --git a/virt/kvm/arm/vgic/vgic.h b/virt/kvm/arm/vgic/vgic.h
index ce57fbd..9bc52ef 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -85,6 +85,13 @@
 #define KVM_ITS_ITE_PINTID_SHIFT       16
 #define KVM_ITS_ITE_PINTID_MASK                GENMASK_ULL(47, 16)
 #define KVM_ITS_ITE_ICID_MASK          GENMASK_ULL(15, 0)
+#define KVM_ITS_DTE_VALID_SHIFT                63
+#define KVM_ITS_DTE_VALID_MASK         BIT_ULL(63)
+#define KVM_ITS_DTE_NEXT_SHIFT         49
+#define KVM_ITS_DTE_NEXT_MASK          GENMASK_ULL(62, 49)
+#define KVM_ITS_DTE_ITTADDR_SHIFT      5
+#define KVM_ITS_DTE_ITTADDR_MASK       GENMASK_ULL(48, 5)
+#define KVM_ITS_DTE_SIZE_MASK          GENMASK_ULL(4, 0)
 
 static inline bool irq_is_pending(struct vgic_irq *irq)
 {
-- 
2.5.5

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