On 3/25/16, 7:14 PM, "kvmarm-bounces@xxxxxxxxxxxxxxxxxxxxx on behalf of Andre Przywara" <kvmarm-bounces@xxxxxxxxxxxxxxxxxxxxx on behalf of andre.przywara@xxxxxxx> wrote:
>The connection between a device, an event ID, the LPI number and the
>allocated CPU is stored in in-memory tables in a GICv3, but their
>format is not specified by the spec. Instead software uses a command
>queue in a ring buffer to let the ITS implementation use their own
>format.
>Implement handlers for the various ITS commands and let them store
>the requested relation into our own data structures.
>To avoid kmallocs inside the ITS spinlock, we preallocate possibly
>needed memory outside of the lock and free that if it turns out to
>be not needed (mostly error handling).
>Error handling is very basic at this point, as we don't have a good
>way of communicating errors to the guest (usually a SError).
>The INT command handler is missing at this point, as we gain the
>capability of actually injecting MSIs into the guest only later on.
>
>Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
>---
> include/linux/irqchip/arm-gic-v3.h | 19 +-
> virt/kvm/arm/vgic/its-emul.c | 514 ++++++++++++++++++++++++++++++++++++-
> 2 files changed, 531 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
>index 7011b98..c9aa8d8 100644
>--- a/include/linux/irqchip/arm-gic-v3.h
>+++ b/include/linux/irqchip/arm-gic-v3.h
>@@ -254,7 +254,10 @@
> */
> #define GITS_CMD_MAPD 0x08
> #define GITS_CMD_MAPC 0x09
>-#define GITS_CMD_MAPVI 0x0a
>+#define GITS_CMD_MAPTI 0x0a
>+/* older GIC documentation used MAPVI for this command */
>+#define GITS_CMD_MAPVI GITS_CMD_MAPTI
>+#define GITS_CMD_MAPI 0x0b
> #define GITS_CMD_MOVI 0x01
> #define GITS_CMD_DISCARD 0x0f
> #define GITS_CMD_INV 0x0c
>@@ -265,6 +268,20 @@
> #define GITS_CMD_SYNC 0x05
>
> /*
>+ * ITS error numbers
>+ */
>+#define E_ITS_MOVI_UNMAPPED_INTERRUPT 0x010107
>+#define E_ITS_MOVI_UNMAPPED_COLLECTION 0x010109
>+#define E_ITS_CLEAR_UNMAPPED_INTERRUPT 0x010507
>+#define E_ITS_MAPC_PROCNUM_OOR 0x010902
>+#define E_ITS_MAPTI_UNMAPPED_DEVICE 0x010a04
>+#define E_ITS_MAPTI_PHYSICALID_OOR 0x010a06
>+#define E_ITS_INV_UNMAPPED_INTERRUPT 0x010c07
>+#define E_ITS_INVALL_UNMAPPED_COLLECTION 0x010d09
>+#define E_ITS_MOVALL_PROCNUM_OOR 0x010e01
>+#define E_ITS_DISCARD_UNMAPPED_INTERRUPT 0x010f07
>+
>+/*
> * CPU interface registers
> */
> #define ICC_CTLR_EL1_EOImode_drop_dir (0U << 1)
>diff --git a/virt/kvm/arm/vgic/its-emul.c b/virt/kvm/arm/vgic/its-emul.c
>index d82ba9b..dcd0cac 100644
>--- a/virt/kvm/arm/vgic/its-emul.c
>+++ b/virt/kvm/arm/vgic/its-emul.c
>@@ -22,6 +22,7 @@
> #include <linux/kvm_host.h>
> #include <linux/interrupt.h>
> #include <linux/list.h>
>+#include <linux/slab.h>
>
> #include <linux/irqchip/arm-gic-v3.h>
>
>@@ -61,6 +62,34 @@ struct its_itte {
> u32 event_id;
> };
>
>+static struct its_device *find_its_device(struct kvm *kvm, u32 device_id)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ struct its_device *device;
>+
>+ list_for_each_entry(device, &its->device_list, dev_list)
>+ if (device_id == device->device_id)
>+ return device;
>+
>+ return NULL;
>+}
>+
>+static struct its_itte *find_itte(struct kvm *kvm, u32 device_id, u32 event_id)
>+{
>+ struct its_device *device;
>+ struct its_itte *itte;
>+
>+ device = find_its_device(kvm, device_id);
>+ if (device == NULL)
>+ return NULL;
>+
>+ list_for_each_entry(itte, &device->itt, 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(dev, itte, kvm) \
> list_for_each_entry(dev, &(kvm)->arch.vgic.its.device_list, dev_list) \
>@@ -78,6 +107,19 @@ static struct its_itte *find_itte_by_lpi(struct kvm *kvm, int lpi)
> return NULL;
> }
>
>+static struct its_collection *find_collection(struct kvm *kvm, int coll_id)
>+{
>+ struct its_collection *collection;
>+
>+ list_for_each_entry(collection, &kvm->arch.vgic.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)
>
>@@ -91,6 +133,29 @@ static void update_lpi_config(struct kvm *kvm, struct its_itte *itte, u8 prop)
> vgic_queue_irq(kvm, &itte->irq);
> }
>
>+/*
>+ * Finds all LPIs which are mapped to this collection and updates the
>+ * struct irq's target_vcpu field accordingly.
>+ * Needs to be called whenever either the collection for a LPIs has
>+ * changed or the collection itself got retargetted.
>+ */
>+static void update_affinity(struct kvm *kvm, struct its_collection *coll)
>+{
>+ struct its_device *device;
>+ struct its_itte *itte;
>+ struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, coll->target_addr);
>+
>+ for_each_lpi(device, itte, kvm) {
>+ if (!itte->collection ||
>+ coll->collection_id != itte->collection->collection_id)
>+ continue;
>+
>+ spin_lock(&itte->irq.irq_lock);
>+ itte->irq.target_vcpu = vcpu;
>+ spin_unlock(&itte->irq.irq_lock);
>+ }
>+}
>+
> #define GIC_LPI_OFFSET 8192
>
> /* We scan the table in chunks the size of the smallest page size */
>@@ -323,13 +388,460 @@ static void its_free_itte(struct its_itte *itte)
> 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). */
>+static int vits_cmd_handle_discard(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ u32 device_id;
>+ u32 event_id;
>+ struct its_itte *itte;
>+ int ret = E_ITS_DISCARD_UNMAPPED_INTERRUPT;
>+
>+ device_id = its_cmd_get_deviceid(its_cmd);
>+ event_id = its_cmd_get_id(its_cmd);
>+
>+ spin_lock(&its->lock);
>+ itte = find_itte(kvm, 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(itte);
>+ ret = 0;
>+ }
>+
>+ spin_unlock(&its->lock);
>+ return ret;
>+}
>+
>+/* The MOVI command moves an ITTE to a different collection. */
>+static int vits_cmd_handle_movi(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ 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_collection *collection;
>+ int ret;
>+
>+ spin_lock(&its->lock);
>+ itte = find_itte(kvm, device_id, event_id);
>+ if (!itte) {
>+ ret = E_ITS_MOVI_UNMAPPED_INTERRUPT;
>+ goto out_unlock;
>+ }
>+ if (!its_is_collection_mapped(itte->collection)) {
>+ ret = E_ITS_MOVI_UNMAPPED_COLLECTION;
>+ goto out_unlock;
>+ }
>+
>+ collection = find_collection(kvm, coll_id);
>+ if (!its_is_collection_mapped(collection)) {
>+ ret = E_ITS_MOVI_UNMAPPED_COLLECTION;
>+ goto out_unlock;
>+ }
>+
>+ itte->collection = collection;
>+ update_affinity(kvm, collection);
>+
Not planning to send this down to Physical ITS in case of VFIO for performance reasons?
>+out_unlock:
>+ spin_unlock(&its->lock);
>+ return ret;
>+}
>+
>+static void vits_init_collection(struct kvm *kvm,
>+ struct its_collection *collection,
>+ u32 coll_id)
>+{
>+ collection->collection_id = coll_id;
>+ collection->target_addr = COLLECTION_NOT_MAPPED;
>+
>+ list_add_tail(&collection->coll_list,
>+ &kvm->arch.vgic.its.collection_list);
>+}
>+
>+/* The MAPTI and MAPI commands map LPIs to ITTEs. */
>+static int vits_cmd_handle_mapi(struct kvm *kvm, u64 *its_cmd, u8 cmd)
>+{
>+ struct vgic_dist *dist = &kvm->arch.vgic;
>+ 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, *new_itte;
>+ struct its_device *device;
>+ struct its_collection *collection, *new_coll;
>+ int lpi_nr;
>+ int ret = 0;
>+
>+ /* Preallocate possibly needed memory here outside of the lock */
>+ new_coll = kmalloc(sizeof(struct its_collection), GFP_KERNEL);
>+ new_itte = kzalloc(sizeof(struct its_itte), GFP_KERNEL);
>+
>+ spin_lock(&dist->its.lock);
>+
>+ device = find_its_device(kvm, device_id);
>+ if (!device) {
>+ ret = E_ITS_MAPTI_UNMAPPED_DEVICE;
>+ goto out_unlock;
>+ }
>+
>+ collection = find_collection(kvm, coll_id);
>+ if (!collection && !new_coll) {
>+ ret = -ENOMEM;
>+ goto out_unlock;
>+ }
>+
>+ if (cmd == 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 >= nr_idbits_propbase(dist->propbaser)) {
>+ ret = E_ITS_MAPTI_PHYSICALID_OOR;
>+ goto out_unlock;
>+ }
>+
>+ itte = find_itte(kvm, device_id, event_id);
>+ if (!itte) {
>+ if (!new_itte) {
>+ ret = -ENOMEM;
>+ goto out_unlock;
>+ }
>+ itte = new_itte;
>+
>+ itte->event_id = event_id;
>+ list_add_tail(&itte->itte_list, &device->itt);
>+ } else {
>+ kfree(new_itte);
>+ }
>+
>+ if (!collection) {
>+ collection = new_coll;
>+ vits_init_collection(kvm, collection, coll_id);
>+ } else {
>+ kfree(new_coll);
>+ }
>+
>+ itte->collection = collection;
>+ itte->lpi = lpi_nr;
>+ itte->irq.intid = lpi_nr;
>+ INIT_LIST_HEAD(&itte->irq.ap_list);
>+ spin_lock_init(&itte->irq.irq_lock);
>+ itte->irq.vcpu = NULL;
>+ update_affinity(kvm, collection);
>+
Same here.
>+out_unlock:
>+ spin_unlock(&dist->its.lock);
>+ if (ret) {
>+ kfree(new_coll);
>+ kfree(new_itte);
>+ }
>+ return ret;
>+}
>+
>+static void vits_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, itte_list)
>+ its_free_itte(itte);
>+
>+ list_del(&device->dev_list);
>+ kfree(device);
>+}
>+
>+/* MAPD maps or unmaps a device ID to Interrupt Translation Tables (ITTs). */
>+static int vits_cmd_handle_mapd(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ bool valid = its_cmd_get_validbit(its_cmd);
>+ u32 device_id = its_cmd_get_deviceid(its_cmd);
>+ struct its_device *device, *new_device = NULL;
>+
>+ /* We preallocate memory outside of the lock here */
>+ if (valid) {
>+ new_device = kzalloc(sizeof(struct its_device), GFP_KERNEL);
>+ if (!new_device)
>+ return -ENOMEM;
>+ }
>+
>+ spin_lock(&its->lock);
>+
>+ device = find_its_device(kvm, device_id);
>+ if (device)
>+ vits_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)
>+ goto out_unlock;
>+
>+ device = new_device;
>+
>+ device->device_id = device_id;
>+ INIT_LIST_HEAD(&device->itt);
>+
>+ list_add_tail(&device->dev_list,
>+ &kvm->arch.vgic.its.device_list);
>+
>+out_unlock:
>+ spin_unlock(&its->lock);
>+ return 0;
>+}
>+
>+/* The MAPC command maps collection IDs to redistributors. */
>+static int vits_cmd_handle_mapc(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ u16 coll_id;
>+ u32 target_addr;
>+ struct its_collection *collection, *new_coll = NULL;
>+ 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;
>+
>+ /* We preallocate memory outside of the lock here */
>+ if (valid) {
>+ new_coll = kmalloc(sizeof(struct its_collection), GFP_KERNEL);
>+ if (!new_coll)
>+ return -ENOMEM;
>+ }
>+
>+ spin_lock(&its->lock);
>+ collection = find_collection(kvm, 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)
>+ goto out_unlock;
>+
>+ for_each_lpi(device, itte, kvm)
>+ if (itte->collection &&
>+ itte->collection->collection_id == coll_id)
>+ itte->collection = NULL;
>+
>+ list_del(&collection->coll_list);
>+ kfree(collection);
>+ } else {
>+ if (!collection)
>+ collection = new_coll;
>+ else
>+ kfree(new_coll);
>+
>+ vits_init_collection(kvm, collection, coll_id);
>+ collection->target_addr = target_addr;
>+ update_affinity(kvm, collection);
>+ }
>+
>+out_unlock:
>+ spin_unlock(&its->lock);
>+ return 0;
>+}
>+
>+/* The CLEAR command removes the pending state for a particular LPI. */
>+static int vits_cmd_handle_clear(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ u32 device_id;
>+ u32 event_id;
>+ struct its_itte *itte;
>+ int ret = 0;
>+
>+ device_id = its_cmd_get_deviceid(its_cmd);
>+ event_id = its_cmd_get_id(its_cmd);
>+
>+ spin_lock(&its->lock);
>+
>+ itte = find_itte(kvm, device_id, event_id);
>+ if (!itte) {
>+ ret = E_ITS_CLEAR_UNMAPPED_INTERRUPT;
>+ goto out_unlock;
>+ }
>+
>+ itte->irq.pending = false;
>+
>+out_unlock:
>+ spin_unlock(&its->lock);
>+ return ret;
>+}
>+
>+/* The INV command syncs the configuration bits from the memory tables. */
>+static int vits_cmd_handle_inv(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_dist *dist = &kvm->arch.vgic;
>+ u32 device_id;
>+ u32 event_id;
>+ struct its_itte *itte, *new_itte;
>+ gpa_t propbase;
>+ int ret;
>+ u8 prop;
>+
>+ device_id = its_cmd_get_deviceid(its_cmd);
>+ event_id = its_cmd_get_id(its_cmd);
>+
>+ spin_lock(&dist->its.lock);
>+ itte = find_itte(kvm, device_id, event_id);
>+ spin_unlock(&dist->its.lock);
>+ if (!itte)
>+ return E_ITS_INV_UNMAPPED_INTERRUPT;
>+
>+ /*
>+ * We cannot read from guest memory inside the spinlock, so we
>+ * need to re-read our tables to learn whether the LPI number we are
>+ * using is still valid.
>+ */
>+ do {
>+ propbase = BASER_BASE_ADDRESS(dist->propbaser);
>+ ret = kvm_read_guest(kvm, propbase + itte->lpi - GIC_LPI_OFFSET,
>+ &prop, 1);
>+ if (ret)
>+ return ret;
>+
>+ spin_lock(&dist->its.lock);
>+ new_itte = find_itte(kvm, device_id, event_id);
>+ if (new_itte->lpi != itte->lpi) {
>+ itte = new_itte;
>+ spin_unlock(&dist->its.lock);
>+ continue;
>+ }
>+ update_lpi_config(kvm, itte, prop);
>+ spin_unlock(&dist->its.lock);
Not possible to call the function defined early and update all. How much performance gain will this be?
>+ } while (0);
>+ return 0;
>+}
>+
>+/* The INVALL command requests flushing of all IRQ data in this collection. */
>+static int vits_cmd_handle_invall(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_dist *dist = &kvm->arch.vgic;
>+ u64 prop_base_reg, pend_base_reg;
>+ u32 coll_id = its_cmd_get_collection(its_cmd);
>+ struct its_collection *collection;
>+ struct kvm_vcpu *vcpu;
>+
>+ collection = find_collection(kvm, coll_id);
>+ if (!its_is_collection_mapped(collection))
>+ return E_ITS_INVALL_UNMAPPED_COLLECTION;
>+
>+ vcpu = kvm_get_vcpu(kvm, collection->target_addr);
>+
>+ pend_base_reg = dist->pendbaser[vcpu->vcpu_id];
>+ prop_base_reg = dist->propbaser;
>+
>+ its_update_lpis_configuration(kvm, prop_base_reg);
>+ its_sync_lpi_pending_table(vcpu, pend_base_reg);
>+
>+ return 0;
>+}
>+
>+/* The MOVALL command moves all IRQs from one redistributor to another. */
>+static int vits_cmd_handle_movall(struct kvm *kvm, u64 *its_cmd)
>+{
>+ struct vgic_its *its = &kvm->arch.vgic.its;
>+ u32 target1_addr = its_cmd_get_target_addr(its_cmd);
>+ u32 target2_addr = its_cmd_mask_field(its_cmd, 3, 16, 32);
>+ struct its_collection *collection;
>+
>+ 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;
>+
>+ spin_lock(&its->lock);
>+ list_for_each_entry(collection, &its->collection_list,
>+ coll_list) {
>+ if (collection && collection->target_addr == target1_addr)
>+ collection->target_addr = target2_addr;
>+ update_affinity(kvm, collection);
>+ }
Not planning to send the commands down in case of VFIO? Think about NUMA systems and performance impact.
>+
>+ spin_unlock(&its->lock);
>+ return 0;
>+}
>+
> /*
> * This function is called with both the ITS and the distributor lock dropped,
> * so the actual command handlers must take the respective locks when needed.
> */
> static int vits_handle_command(struct kvm_vcpu *vcpu, u64 *its_cmd)
> {
>- return -ENODEV;
>+ u8 cmd = its_cmd_get_command(its_cmd);
>+ int ret = -ENODEV;
>+
>+ switch (cmd) {
>+ case GITS_CMD_MAPD:
>+ ret = vits_cmd_handle_mapd(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_MAPC:
>+ ret = vits_cmd_handle_mapc(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_MAPI:
>+ ret = vits_cmd_handle_mapi(vcpu->kvm, its_cmd, cmd);
>+ break;
>+ case GITS_CMD_MAPTI:
>+ ret = vits_cmd_handle_mapi(vcpu->kvm, its_cmd, cmd);
>+ break;
>+ case GITS_CMD_MOVI:
>+ ret = vits_cmd_handle_movi(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_DISCARD:
>+ ret = vits_cmd_handle_discard(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_CLEAR:
>+ ret = vits_cmd_handle_clear(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_MOVALL:
>+ ret = vits_cmd_handle_movall(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_INV:
>+ ret = vits_cmd_handle_inv(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_INVALL:
>+ ret = vits_cmd_handle_invall(vcpu->kvm, its_cmd);
>+ break;
>+ case GITS_CMD_SYNC:
>+ /* we ignore this command: we are in sync all of the time */
>+ ret = 0;
>+ break;
>+ }
>+
>+ return ret;
> }
>
> static int vgic_mmio_read_its_cbaser(struct kvm_vcpu *vcpu,
>--
>2.7.3
>
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