[PATCH v5 20/22] KVM: arm64: vgic-its: Device table save/restore

Eric Auger
2017-04-14T10:15:32Z

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 <eric.auger@redhat.com>

---
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