[PULL 23/37] KVM: arm64: vgic-its: Device table save/restore

Christoffer Dall
2017-05-09T10:42:25Z

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. Those functions will be implemented in a subsequent
patch.

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

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
---
virt/kvm/arm/vgic/vgic-its.c | 194 +++++++++++++++++++++++++++++++++++++++++--
virt/kvm/arm/vgic/vgic.h | 10 +++
2 files changed, 199 insertions(+), 5 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
index 90afc83..3dea626 100644
--- a/virt/kvm/arm/vgic/vgic-its.c
+++ b/virt/kvm/arm/vgic/vgic-its.c
@@ -23,6 +23,7 @@
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/uaccess.h>
+#include <linux/list_sort.h>

#include <linux/irqchip/arm-gic-v3.h>

@@ -1735,7 +1736,8 @@ 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 its_device *next;
u32 next_offset;
@@ -1789,8 +1791,8 @@ typedef int (*entry_fn_t)(struct vgic_its *its, u32 id, void *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)
+static 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;
@@ -1825,13 +1827,171 @@ int scan_its_table(struct vgic_its *its, gpa_t base, int size, int esz,
return ret;
}

+static int vgic_its_save_itt(struct vgic_its *its, struct its_device *device)
+{
+ return -ENXIO;
+}
+
+static int vgic_its_restore_itt(struct vgic_its *its, struct its_device *dev)
+{
+ return -ENXIO;
+}
+
+/**
+ * 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;
+ 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->num_eventid_bits - 1));
+ val = cpu_to_le64(val);
+ return kvm_write_guest(kvm, ptr, &val, dte_esz);
+}
+
+/**
+ * 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
+ *
+ * Return: < 0 on error, 0 if the dte is the last one, id offset to the
+ * next dte otherwise
+ */
+static int vgic_its_restore_dte(struct vgic_its *its, u32 id,
+ void *ptr, void *opaque)
+{
+ struct its_device *dev;
+ gpa_t itt_addr;
+ u8 num_eventid_bits;
+ u64 entry = *(u64 *)ptr;
+ bool valid;
+ u32 offset;
+ int ret;
+
+ entry = le64_to_cpu(entry);
+
+ valid = entry >> KVM_ITS_DTE_VALID_SHIFT;
+ num_eventid_bits = (entry & KVM_ITS_DTE_SIZE_MASK) + 1;
+ itt_addr = ((entry & KVM_ITS_DTE_ITTADDR_MASK)
+ >> KVM_ITS_DTE_ITTADDR_SHIFT) << 8;
+
+ if (!valid)
+ return 1;
+
+ /* dte entry is valid */
+ offset = (entry & KVM_ITS_DTE_NEXT_MASK) >> KVM_ITS_DTE_NEXT_SHIFT;
+
+ dev = vgic_its_alloc_device(its, id, itt_addr, num_eventid_bits);
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
+
+ ret = vgic_its_restore_itt(its, dev);
+ if (ret)
+ return ret;
+
+ return offset;
+}
+
+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_dte - callback used for L1 device table entries (2 stage case)
+ *
+ * @its: its handle
+ * @id: index of the entry in the L1 table
+ * @addr: kernel VA
+ * @opaque: unused
+ *
+ * L1 table entries are scanned by steps of 1 entry
+ * Return < 0 if error, 0 if last dte was found when scanning the L2
+ * table, +1 otherwise (meaning next L1 entry must be scanned)
+ */
+static int handle_l1_dte(struct vgic_its *its, u32 id, void *addr,
+ void *opaque)
+{
+ const struct vgic_its_abi *abi = vgic_its_get_abi(its);
+ int l2_start_id = id * (SZ_64K / abi->dte_esz);
+ u64 entry = *(u64 *)addr;
+ int dte_esz = abi->dte_esz;
+ gpa_t gpa;
+ int ret;
+
+ entry = le64_to_cpu(entry);
+
+ if (!(entry & KVM_ITS_L1E_VALID_MASK))
+ return 1;
+
+ gpa = entry & KVM_ITS_L1E_ADDR_MASK;
+
+ ret = scan_its_table(its, gpa, SZ_64K, dte_esz,
+ l2_start_id, vgic_its_restore_dte, NULL);
+
+ if (ret <= 0)
+ return ret;
+
+ return 1;
}

/**
@@ -1840,7 +2000,31 @@ 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;
+ int l1_tbl_size = GITS_BASER_NR_PAGES(baser) * SZ_64K;
+ gpa_t l1_gpa;
+
+ if (!(baser & GITS_BASER_VALID))
+ return 0;
+
+ l1_gpa = BASER_ADDRESS(baser);
+
+ if (baser & GITS_BASER_INDIRECT) {
+ l1_esz = GITS_LVL1_ENTRY_SIZE;
+ ret = scan_its_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,
+ handle_l1_dte, NULL);
+ } else {
+ l1_esz = abi->dte_esz;
+ ret = scan_its_table(its, l1_gpa, l1_tbl_size, l1_esz, 0,
+ vgic_its_restore_dte, NULL);
+ }
+
+ if (ret > 0)
+ ret = -EINVAL;
+
+ return ret;
}

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 757de7a..f35e993 100644
--- a/virt/kvm/arm/vgic/vgic.h
+++ b/virt/kvm/arm/vgic/vgic.h
@@ -81,6 +81,16 @@
#define KVM_ITS_CTE_VALID_MASK BIT_ULL(63)
#define KVM_ITS_CTE_RDBASE_SHIFT 16
#define KVM_ITS_CTE_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)
+#define KVM_ITS_L1E_VALID_MASK BIT_ULL(63)
+/* we only support 64 kB translation table page size */
+#define KVM_ITS_L1E_ADDR_MASK GENMASK_ULL(51, 16)

static inline bool irq_is_pending(struct vgic_irq *irq)
{
--
2.9.0