Message ID | 153902587240.8888.10231126153251311895.stgit@kernel |
---|---|
State | Changes Requested, archived |
Delegated to: | BPF Maintainers |
Headers | show |
Series | Implement queue/stack maps | expand |
On Mon, Oct 8, 2018 at 12:12 PM Mauricio Vasquez B <mauricio.vasquez@polito.it> wrote: > > Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs. > These maps support peek, pop and push operations that are exposed to eBPF > programs through the new bpf_map[peek/pop/push] helpers. Those operations > are exposed to userspace applications through the already existing > syscalls in the following way: > > BPF_MAP_LOOKUP_ELEM -> peek > BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop > BPF_MAP_UPDATE_ELEM -> push > > Queue/stack maps are implemented using a buffer, tail and head indexes, > hence BPF_F_NO_PREALLOC is not supported. > > As opposite to other maps, queue and stack do not use RCU for protecting > maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE > argument that is a pointer to a memory zone where to save the value of a > map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not > be passed as an extra argument. > > Our main motivation for implementing queue/stack maps was to keep track > of a pool of elements, like network ports in a SNAT, however we forsee > other use cases, like for exampling saving last N kernel events in a map > and then analysing from userspace. > > Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it> > --- > include/linux/bpf.h | 7 + > include/linux/bpf_types.h | 2 > include/uapi/linux/bpf.h | 35 ++++- > kernel/bpf/Makefile | 2 > kernel/bpf/core.c | 3 > kernel/bpf/helpers.c | 43 ++++++ > kernel/bpf/queue_stack_maps.c | 288 +++++++++++++++++++++++++++++++++++++++++ > kernel/bpf/syscall.c | 30 +++- > kernel/bpf/verifier.c | 28 +++- > net/core/filter.c | 6 + > 10 files changed, 426 insertions(+), 18 deletions(-) > create mode 100644 kernel/bpf/queue_stack_maps.c > > diff --git a/include/linux/bpf.h b/include/linux/bpf.h > index 98c7eeb6d138..cad3bc5cffd1 100644 > --- a/include/linux/bpf.h > +++ b/include/linux/bpf.h > @@ -40,6 +40,9 @@ struct bpf_map_ops { > int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); > int (*map_delete_elem)(struct bpf_map *map, void *key); > void *(*map_lookup_and_delete_elem)(struct bpf_map *map, void *key); > + int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags); > + int (*map_pop_elem)(struct bpf_map *map, void *value); > + int (*map_peek_elem)(struct bpf_map *map, void *value); > > /* funcs called by prog_array and perf_event_array map */ > void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, > @@ -139,6 +142,7 @@ enum bpf_arg_type { > ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ > ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ > ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ > + ARG_PTR_TO_UNINIT_MAP_VALUE, /* pointer to valid memory used to store a map value */ How about we put ARG_PTR_TO_UNINIT_MAP_VALUE and related logic to a separate patch? > > /* the following constraints used to prototype bpf_memcmp() and other > * functions that access data on eBPF program stack > @@ -825,6 +829,9 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, > extern const struct bpf_func_proto bpf_map_lookup_elem_proto; > extern const struct bpf_func_proto bpf_map_update_elem_proto; > extern const struct bpf_func_proto bpf_map_delete_elem_proto; > +extern const struct bpf_func_proto bpf_map_push_elem_proto; > +extern const struct bpf_func_proto bpf_map_pop_elem_proto; > +extern const struct bpf_func_proto bpf_map_peek_elem_proto; > > extern const struct bpf_func_proto bpf_get_prandom_u32_proto; > extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h > index 658509daacd4..a2ec73aa1ec7 100644 > --- a/include/linux/bpf_types.h > +++ b/include/linux/bpf_types.h > @@ -69,3 +69,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) > BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) > #endif > #endif > +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) > +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index 3bb94aa2d408..bfa042273fad 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -129,6 +129,8 @@ enum bpf_map_type { > BPF_MAP_TYPE_CGROUP_STORAGE, > BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, > BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, > + BPF_MAP_TYPE_QUEUE, > + BPF_MAP_TYPE_STACK, > }; > > enum bpf_prog_type { > @@ -463,6 +465,28 @@ union bpf_attr { > * Return > * 0 on success, or a negative error in case of failure. > * > + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) > + * Description > + * Push an element *value* in *map*. *flags* is one of: > + * > + * **BPF_EXIST** > + * If the queue/stack is full, the oldest element is removed to > + * make room for this. > + * Return > + * 0 on success, or a negative error in case of failure. > + * > + * int bpf_map_pop_elem(struct bpf_map *map, void *value) > + * Description > + * Pop an element from *map*. > + * Return > + * 0 on success, or a negative error in case of failure. > + * > + * int bpf_map_peek_elem(struct bpf_map *map, void *value) > + * Description > + * Get an element from *map* without removing it. > + * Return > + * 0 on success, or a negative error in case of failure. > + * > * int bpf_probe_read(void *dst, u32 size, const void *src) > * Description > * For tracing programs, safely attempt to read *size* bytes from > @@ -790,14 +814,14 @@ union bpf_attr { > * > * int ret; > * struct bpf_tunnel_key key = {}; > - * > + * > * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0); > * if (ret < 0) > * return TC_ACT_SHOT; // drop packet > - * > + * > * if (key.remote_ipv4 != 0x0a000001) > * return TC_ACT_SHOT; // drop packet > - * > + * > * return TC_ACT_OK; // accept packet > * > * This interface can also be used with all encapsulation devices > @@ -2304,7 +2328,10 @@ union bpf_attr { > FN(skb_ancestor_cgroup_id), \ > FN(sk_lookup_tcp), \ > FN(sk_lookup_udp), \ > - FN(sk_release), > + FN(sk_release), \ > + FN(map_push_elem), \ > + FN(map_pop_elem), \ > + FN(map_peek_elem), > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > * function eBPF program intends to call > diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile > index 0488b8258321..17afae9e65f3 100644 > --- a/kernel/bpf/Makefile > +++ b/kernel/bpf/Makefile > @@ -3,7 +3,7 @@ obj-y := core.o > > obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o > obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o > -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o > +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o > obj-$(CONFIG_BPF_SYSCALL) += disasm.o > obj-$(CONFIG_BPF_SYSCALL) += btf.o > ifeq ($(CONFIG_NET),y) > diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > index 3f5bf1af0826..8d2db076d123 100644 > --- a/kernel/bpf/core.c > +++ b/kernel/bpf/core.c > @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) > const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; > const struct bpf_func_proto bpf_map_update_elem_proto __weak; > const struct bpf_func_proto bpf_map_delete_elem_proto __weak; > +const struct bpf_func_proto bpf_map_push_elem_proto __weak; > +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; > +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; > > const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; > const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > index 6502115e8f55..ab0d5e3f9892 100644 > --- a/kernel/bpf/helpers.c > +++ b/kernel/bpf/helpers.c > @@ -76,6 +76,49 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { > .arg2_type = ARG_PTR_TO_MAP_KEY, > }; > > +BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags) > +{ > + return map->ops->map_push_elem(map, value, flags); > +} > + > +const struct bpf_func_proto bpf_map_push_elem_proto = { > + .func = bpf_map_push_elem, > + .gpl_only = false, > + .pkt_access = true, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_CONST_MAP_PTR, > + .arg2_type = ARG_PTR_TO_MAP_VALUE, > + .arg3_type = ARG_ANYTHING, > +}; > + > +BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value) > +{ > + return map->ops->map_pop_elem(map, value); > +} > + > +const struct bpf_func_proto bpf_map_pop_elem_proto = { > + .func = bpf_map_pop_elem, > + .gpl_only = false, > + .pkt_access = true, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_CONST_MAP_PTR, > + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, > +}; > + > +BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value) > +{ > + return map->ops->map_peek_elem(map, value); > +} > + > +const struct bpf_func_proto bpf_map_peek_elem_proto = { > + .func = bpf_map_pop_elem, > + .gpl_only = false, > + .pkt_access = true, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_CONST_MAP_PTR, > + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, > +}; > + > const struct bpf_func_proto bpf_get_prandom_u32_proto = { > .func = bpf_user_rnd_u32, > .gpl_only = false, > diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c > new file mode 100644 > index 000000000000..12a93fb37449 > --- /dev/null > +++ b/kernel/bpf/queue_stack_maps.c > @@ -0,0 +1,288 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * queue_stack_maps.c: BPF queue and stack maps > + * > + * Copyright (c) 2018 Politecnico di Torino > + */ > +#include <linux/bpf.h> > +#include <linux/list.h> > +#include <linux/slab.h> > +#include "percpu_freelist.h" > + > +#define QUEUE_STACK_CREATE_FLAG_MASK \ > + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) > + > + > +struct bpf_queue_stack { > + struct bpf_map map; > + raw_spinlock_t lock; > + u32 head, tail; > + u32 size; /* max_entries + 1 */ > + > + char elements[0] __aligned(8); > +}; > + > +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) > +{ > + return container_of(map, struct bpf_queue_stack, map); > +} > + > +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) > +{ > + return qs->head == qs->tail; > +} > + > +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) > +{ > + u32 head = qs->head + 1; > + > + if (unlikely(head >= qs->size)) > + head = 0; > + > + return head == qs->tail; > +} > + > +/* Called from syscall */ > +static int queue_stack_map_alloc_check(union bpf_attr *attr) > +{ > + /* check sanity of attributes */ > + if (attr->max_entries == 0 || attr->key_size != 0 || > + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK) > + return -EINVAL; > + > + if (attr->value_size > KMALLOC_MAX_SIZE) > + /* if value_size is bigger, the user space won't be able to > + * access the elements. > + */ > + return -E2BIG; > + > + return 0; > +} > + > +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) > +{ > + int ret, numa_node = bpf_map_attr_numa_node(attr); > + struct bpf_queue_stack *qs; > + u32 size, value_size; > + u64 queue_size, cost; > + > + size = attr->max_entries + 1; > + value_size = attr->value_size; > + > + queue_size = sizeof(*qs) + (u64) value_size * size; > + > + cost = queue_size; > + if (cost >= U32_MAX - PAGE_SIZE) > + return ERR_PTR(-E2BIG); > + > + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; > + > + ret = bpf_map_precharge_memlock(cost); > + if (ret < 0) > + return ERR_PTR(ret); > + > + qs = bpf_map_area_alloc(queue_size, numa_node); > + if (!qs) > + return ERR_PTR(-ENOMEM); > + > + memset(qs, 0, sizeof(*qs)); > + > + bpf_map_init_from_attr(&qs->map, attr); > + > + qs->map.pages = cost; > + qs->size = size; > + > + raw_spin_lock_init(&qs->lock); > + > + return &qs->map; > +} > + > +/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ > +static void queue_stack_map_free(struct bpf_map *map) > +{ > + struct bpf_queue_stack *qs = bpf_queue_stack(map); > + > + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, > + * so the programs (can be more than one that used this map) were > + * disconnected from events. Wait for outstanding critical sections in > + * these programs to complete > + */ > + synchronize_rcu(); > + > + bpf_map_area_free(qs); > +} > + > +static int __queue_map_get(struct bpf_map *map, void *value, bool delete) > +{ > + struct bpf_queue_stack *qs = bpf_queue_stack(map); > + unsigned long flags; > + int err = 0; > + void *ptr; > + > + raw_spin_lock_irqsave(&qs->lock, flags); > + > + if (queue_stack_map_is_empty(qs)) { > + err = -ENOENT; > + goto out; > + } > + > + ptr = &qs->elements[qs->tail * qs->map.value_size]; > + memcpy(value, ptr, qs->map.value_size); > + > + if (delete) { > + if (unlikely(++qs->tail >= qs->size)) > + qs->tail = 0; > + } > + > +out: > + raw_spin_unlock_irqrestore(&qs->lock, flags); > + return err; > +} > + > + > +static int __stack_map_get(struct bpf_map *map, void *value, bool delete) > +{ > + struct bpf_queue_stack *qs = bpf_queue_stack(map); > + unsigned long flags; > + int err = 0; > + void *ptr; > + u32 index; > + > + raw_spin_lock_irqsave(&qs->lock, flags); > + > + if (queue_stack_map_is_empty(qs)) { > + err = -ENOENT; > + goto out; > + } > + > + index = qs->head - 1; > + if (unlikely(index >= qs->size)) > + index = qs->size - 1; > + > + ptr = &qs->elements[index * qs->map.value_size]; > + memcpy(value, ptr, qs->map.value_size); > + > + if (delete) > + qs->head = index; > + > +out: > + raw_spin_unlock_irqrestore(&qs->lock, flags); > + return err; > +} > + > +/* Called from syscall or from eBPF program */ > +static int queue_map_peek_elem(struct bpf_map *map, void *value) > +{ > + return __queue_map_get(map, value, false); > +} > + > +/* Called from syscall or from eBPF program */ > +static int stack_map_peek_elem(struct bpf_map *map, void *value) > +{ > + return __stack_map_get(map, value, false); > +} > + > +/* Called from syscall or from eBPF program */ > +static int queue_map_pop_elem(struct bpf_map *map, void *value) > +{ > + return __queue_map_get(map, value, true); > +} > + > +/* Called from syscall or from eBPF program */ > +static int stack_map_pop_elem(struct bpf_map *map, void *value) > +{ > + return __stack_map_get(map, value, true); > +} > + > +/* Called from syscall or from eBPF program */ > +static int queue_stack_map_push_elem(struct bpf_map *map, void *value, > + u64 flags) > +{ > + struct bpf_queue_stack *qs = bpf_queue_stack(map); > + unsigned long irq_flags; > + int err = 0; > + void *dst; > + > + /* BPF_EXIST is used to force making room for a new element in case the > + * map is full > + */ > + bool replace = (flags & BPF_EXIST); > + > + /* Check supported flags for queue and stack maps */ > + if (flags & BPF_NOEXIST || flags > BPF_EXIST) > + return -EINVAL; > + > + raw_spin_lock_irqsave(&qs->lock, irq_flags); > + > + if (queue_stack_map_is_full(qs)) { > + if (!replace) { > + err = -E2BIG; > + goto out; > + } > + /* advance tail pointer to overwrite oldest element */ > + if (unlikely(++qs->tail >= qs->size)) > + qs->tail = 0; > + } > + > + dst = &qs->elements[qs->head * qs->map.value_size]; > + memcpy(dst, value, qs->map.value_size); > + > + if (unlikely(++qs->head >= qs->size)) > + qs->head = 0; > + > +out: > + raw_spin_unlock_irqrestore(&qs->lock, irq_flags); > + return err; > +} > + > +/* Called from syscall or from eBPF program */ > +static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key) > +{ > + return NULL; > +} > + > +/* Called from syscall or from eBPF program */ > +static int queue_stack_map_update_elem(struct bpf_map *map, void *key, > + void *value, u64 flags) > +{ > + return -EINVAL; > +} > + > +/* Called from syscall or from eBPF program */ > +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) > +{ > + return -EINVAL; > +} > + > +/* Called from syscall */ > +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, > + void *next_key) > +{ > + return -EINVAL; > +} > + > +const struct bpf_map_ops queue_map_ops = { > + .map_alloc_check = queue_stack_map_alloc_check, > + .map_alloc = queue_stack_map_alloc, > + .map_free = queue_stack_map_free, > + .map_lookup_elem = queue_stack_map_lookup_elem, > + .map_update_elem = queue_stack_map_update_elem, > + .map_delete_elem = queue_stack_map_delete_elem, > + .map_push_elem = queue_stack_map_push_elem, > + .map_pop_elem = queue_map_pop_elem, > + .map_peek_elem = queue_map_peek_elem, > + .map_get_next_key = queue_stack_map_get_next_key, > +}; > + > +const struct bpf_map_ops stack_map_ops = { > + .map_alloc_check = queue_stack_map_alloc_check, > + .map_alloc = queue_stack_map_alloc, > + .map_free = queue_stack_map_free, > + .map_lookup_elem = queue_stack_map_lookup_elem, > + .map_update_elem = queue_stack_map_update_elem, > + .map_delete_elem = queue_stack_map_delete_elem, > + .map_push_elem = queue_stack_map_push_elem, > + .map_pop_elem = stack_map_pop_elem, > + .map_peek_elem = stack_map_peek_elem, > + .map_get_next_key = queue_stack_map_get_next_key, > +}; > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index c33d9303f72f..c135d205fd09 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -727,6 +727,9 @@ static int map_lookup_elem(union bpf_attr *attr) > err = bpf_fd_htab_map_lookup_elem(map, key, value); > } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) { > err = bpf_fd_reuseport_array_lookup_elem(map, key, value); > + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || > + map->map_type == BPF_MAP_TYPE_STACK) { > + err = map->ops->map_peek_elem(map, value); > } else { > rcu_read_lock(); > ptr = map->ops->map_lookup_elem(map, key); > @@ -841,6 +844,9 @@ static int map_update_elem(union bpf_attr *attr) > /* rcu_read_lock() is not needed */ > err = bpf_fd_reuseport_array_update_elem(map, key, value, > attr->flags); > + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || > + map->map_type == BPF_MAP_TYPE_STACK) { > + err = map->ops->map_push_elem(map, value, attr->flags); > } else { > rcu_read_lock(); > err = map->ops->map_update_elem(map, key, value, attr->flags); > @@ -1023,16 +1029,22 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) > */ > preempt_disable(); > __this_cpu_inc(bpf_prog_active); > - if (!map->ops->map_lookup_and_delete_elem) { > - err = -ENOTSUPP; > - goto free_value; > + if (map->map_type == BPF_MAP_TYPE_QUEUE || > + map->map_type == BPF_MAP_TYPE_STACK) { > + err = map->ops->map_pop_elem(map, value); > + } else { > + if (!map->ops->map_lookup_and_delete_elem) { > + err = -ENOTSUPP; > + goto free_value; similar to previous patch: either we move this check, or we add __this_cpu_dec() and preempt_enable(). Thanks, Song
On 10/08/2018 08:36 PM, Song Liu wrote: > On Mon, Oct 8, 2018 at 12:12 PM Mauricio Vasquez B > <mauricio.vasquez@polito.it> wrote: >> Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs. >> These maps support peek, pop and push operations that are exposed to eBPF >> programs through the new bpf_map[peek/pop/push] helpers. Those operations >> are exposed to userspace applications through the already existing >> syscalls in the following way: >> >> BPF_MAP_LOOKUP_ELEM -> peek >> BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop >> BPF_MAP_UPDATE_ELEM -> push >> >> Queue/stack maps are implemented using a buffer, tail and head indexes, >> hence BPF_F_NO_PREALLOC is not supported. >> >> As opposite to other maps, queue and stack do not use RCU for protecting >> maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE >> argument that is a pointer to a memory zone where to save the value of a >> map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not >> be passed as an extra argument. >> >> Our main motivation for implementing queue/stack maps was to keep track >> of a pool of elements, like network ports in a SNAT, however we forsee >> other use cases, like for exampling saving last N kernel events in a map >> and then analysing from userspace. >> >> Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it> >> --- >> include/linux/bpf.h | 7 + >> include/linux/bpf_types.h | 2 >> include/uapi/linux/bpf.h | 35 ++++- >> kernel/bpf/Makefile | 2 >> kernel/bpf/core.c | 3 >> kernel/bpf/helpers.c | 43 ++++++ >> kernel/bpf/queue_stack_maps.c | 288 +++++++++++++++++++++++++++++++++++++++++ >> kernel/bpf/syscall.c | 30 +++- >> kernel/bpf/verifier.c | 28 +++- >> net/core/filter.c | 6 + >> 10 files changed, 426 insertions(+), 18 deletions(-) >> create mode 100644 kernel/bpf/queue_stack_maps.c >> >> diff --git a/include/linux/bpf.h b/include/linux/bpf.h >> index 98c7eeb6d138..cad3bc5cffd1 100644 >> --- a/include/linux/bpf.h >> +++ b/include/linux/bpf.h >> @@ -40,6 +40,9 @@ struct bpf_map_ops { >> int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); >> int (*map_delete_elem)(struct bpf_map *map, void *key); >> void *(*map_lookup_and_delete_elem)(struct bpf_map *map, void *key); >> + int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags); >> + int (*map_pop_elem)(struct bpf_map *map, void *value); >> + int (*map_peek_elem)(struct bpf_map *map, void *value); >> >> /* funcs called by prog_array and perf_event_array map */ >> void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, >> @@ -139,6 +142,7 @@ enum bpf_arg_type { >> ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ >> ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ >> ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ >> + ARG_PTR_TO_UNINIT_MAP_VALUE, /* pointer to valid memory used to store a map value */ > How about we put ARG_PTR_TO_UNINIT_MAP_VALUE and related logic to a > separate patch? I thought it too, but this is a really small change (6 additions, 3 deletions). Does it worth a separated patch? > >> /* the following constraints used to prototype bpf_memcmp() and other >> * functions that access data on eBPF program stack >> @@ -825,6 +829,9 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, >> extern const struct bpf_func_proto bpf_map_lookup_elem_proto; >> extern const struct bpf_func_proto bpf_map_update_elem_proto; >> extern const struct bpf_func_proto bpf_map_delete_elem_proto; >> +extern const struct bpf_func_proto bpf_map_push_elem_proto; >> +extern const struct bpf_func_proto bpf_map_pop_elem_proto; >> +extern const struct bpf_func_proto bpf_map_peek_elem_proto; >> >> extern const struct bpf_func_proto bpf_get_prandom_u32_proto; >> extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; >> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h >> index 658509daacd4..a2ec73aa1ec7 100644 >> --- a/include/linux/bpf_types.h >> +++ b/include/linux/bpf_types.h >> @@ -69,3 +69,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) >> BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) >> #endif >> #endif >> +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) >> +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) >> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h >> index 3bb94aa2d408..bfa042273fad 100644 >> --- a/include/uapi/linux/bpf.h >> +++ b/include/uapi/linux/bpf.h >> @@ -129,6 +129,8 @@ enum bpf_map_type { >> BPF_MAP_TYPE_CGROUP_STORAGE, >> BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, >> BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, >> + BPF_MAP_TYPE_QUEUE, >> + BPF_MAP_TYPE_STACK, >> }; >> >> enum bpf_prog_type { >> @@ -463,6 +465,28 @@ union bpf_attr { >> * Return >> * 0 on success, or a negative error in case of failure. >> * >> + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) >> + * Description >> + * Push an element *value* in *map*. *flags* is one of: >> + * >> + * **BPF_EXIST** >> + * If the queue/stack is full, the oldest element is removed to >> + * make room for this. >> + * Return >> + * 0 on success, or a negative error in case of failure. >> + * >> + * int bpf_map_pop_elem(struct bpf_map *map, void *value) >> + * Description >> + * Pop an element from *map*. >> + * Return >> + * 0 on success, or a negative error in case of failure. >> + * >> + * int bpf_map_peek_elem(struct bpf_map *map, void *value) >> + * Description >> + * Get an element from *map* without removing it. >> + * Return >> + * 0 on success, or a negative error in case of failure. >> + * >> * int bpf_probe_read(void *dst, u32 size, const void *src) >> * Description >> * For tracing programs, safely attempt to read *size* bytes from >> @@ -790,14 +814,14 @@ union bpf_attr { >> * >> * int ret; >> * struct bpf_tunnel_key key = {}; >> - * >> + * >> * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0); >> * if (ret < 0) >> * return TC_ACT_SHOT; // drop packet >> - * >> + * >> * if (key.remote_ipv4 != 0x0a000001) >> * return TC_ACT_SHOT; // drop packet >> - * >> + * >> * return TC_ACT_OK; // accept packet >> * >> * This interface can also be used with all encapsulation devices >> @@ -2304,7 +2328,10 @@ union bpf_attr { >> FN(skb_ancestor_cgroup_id), \ >> FN(sk_lookup_tcp), \ >> FN(sk_lookup_udp), \ >> - FN(sk_release), >> + FN(sk_release), \ >> + FN(map_push_elem), \ >> + FN(map_pop_elem), \ >> + FN(map_peek_elem), >> >> /* integer value in 'imm' field of BPF_CALL instruction selects which helper >> * function eBPF program intends to call >> diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile >> index 0488b8258321..17afae9e65f3 100644 >> --- a/kernel/bpf/Makefile >> +++ b/kernel/bpf/Makefile >> @@ -3,7 +3,7 @@ obj-y := core.o >> >> obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o >> obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o >> -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o >> +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o >> obj-$(CONFIG_BPF_SYSCALL) += disasm.o >> obj-$(CONFIG_BPF_SYSCALL) += btf.o >> ifeq ($(CONFIG_NET),y) >> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c >> index 3f5bf1af0826..8d2db076d123 100644 >> --- a/kernel/bpf/core.c >> +++ b/kernel/bpf/core.c >> @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) >> const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; >> const struct bpf_func_proto bpf_map_update_elem_proto __weak; >> const struct bpf_func_proto bpf_map_delete_elem_proto __weak; >> +const struct bpf_func_proto bpf_map_push_elem_proto __weak; >> +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; >> +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; >> >> const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; >> const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; >> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c >> index 6502115e8f55..ab0d5e3f9892 100644 >> --- a/kernel/bpf/helpers.c >> +++ b/kernel/bpf/helpers.c >> @@ -76,6 +76,49 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { >> .arg2_type = ARG_PTR_TO_MAP_KEY, >> }; >> >> +BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags) >> +{ >> + return map->ops->map_push_elem(map, value, flags); >> +} >> + >> +const struct bpf_func_proto bpf_map_push_elem_proto = { >> + .func = bpf_map_push_elem, >> + .gpl_only = false, >> + .pkt_access = true, >> + .ret_type = RET_INTEGER, >> + .arg1_type = ARG_CONST_MAP_PTR, >> + .arg2_type = ARG_PTR_TO_MAP_VALUE, >> + .arg3_type = ARG_ANYTHING, >> +}; >> + >> +BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value) >> +{ >> + return map->ops->map_pop_elem(map, value); >> +} >> + >> +const struct bpf_func_proto bpf_map_pop_elem_proto = { >> + .func = bpf_map_pop_elem, >> + .gpl_only = false, >> + .pkt_access = true, >> + .ret_type = RET_INTEGER, >> + .arg1_type = ARG_CONST_MAP_PTR, >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, >> +}; >> + >> +BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value) >> +{ >> + return map->ops->map_peek_elem(map, value); >> +} >> + >> +const struct bpf_func_proto bpf_map_peek_elem_proto = { >> + .func = bpf_map_pop_elem, >> + .gpl_only = false, >> + .pkt_access = true, >> + .ret_type = RET_INTEGER, >> + .arg1_type = ARG_CONST_MAP_PTR, >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, >> +}; >> + >> const struct bpf_func_proto bpf_get_prandom_u32_proto = { >> .func = bpf_user_rnd_u32, >> .gpl_only = false, >> diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c >> new file mode 100644 >> index 000000000000..12a93fb37449 >> --- /dev/null >> +++ b/kernel/bpf/queue_stack_maps.c >> @@ -0,0 +1,288 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * queue_stack_maps.c: BPF queue and stack maps >> + * >> + * Copyright (c) 2018 Politecnico di Torino >> + */ >> +#include <linux/bpf.h> >> +#include <linux/list.h> >> +#include <linux/slab.h> >> +#include "percpu_freelist.h" >> + >> +#define QUEUE_STACK_CREATE_FLAG_MASK \ >> + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) >> + >> + >> +struct bpf_queue_stack { >> + struct bpf_map map; >> + raw_spinlock_t lock; >> + u32 head, tail; >> + u32 size; /* max_entries + 1 */ >> + >> + char elements[0] __aligned(8); >> +}; >> + >> +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) >> +{ >> + return container_of(map, struct bpf_queue_stack, map); >> +} >> + >> +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) >> +{ >> + return qs->head == qs->tail; >> +} >> + >> +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) >> +{ >> + u32 head = qs->head + 1; >> + >> + if (unlikely(head >= qs->size)) >> + head = 0; >> + >> + return head == qs->tail; >> +} >> + >> +/* Called from syscall */ >> +static int queue_stack_map_alloc_check(union bpf_attr *attr) >> +{ >> + /* check sanity of attributes */ >> + if (attr->max_entries == 0 || attr->key_size != 0 || >> + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK) >> + return -EINVAL; >> + >> + if (attr->value_size > KMALLOC_MAX_SIZE) >> + /* if value_size is bigger, the user space won't be able to >> + * access the elements. >> + */ >> + return -E2BIG; >> + >> + return 0; >> +} >> + >> +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) >> +{ >> + int ret, numa_node = bpf_map_attr_numa_node(attr); >> + struct bpf_queue_stack *qs; >> + u32 size, value_size; >> + u64 queue_size, cost; >> + >> + size = attr->max_entries + 1; >> + value_size = attr->value_size; >> + >> + queue_size = sizeof(*qs) + (u64) value_size * size; >> + >> + cost = queue_size; >> + if (cost >= U32_MAX - PAGE_SIZE) >> + return ERR_PTR(-E2BIG); >> + >> + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; >> + >> + ret = bpf_map_precharge_memlock(cost); >> + if (ret < 0) >> + return ERR_PTR(ret); >> + >> + qs = bpf_map_area_alloc(queue_size, numa_node); >> + if (!qs) >> + return ERR_PTR(-ENOMEM); >> + >> + memset(qs, 0, sizeof(*qs)); >> + >> + bpf_map_init_from_attr(&qs->map, attr); >> + >> + qs->map.pages = cost; >> + qs->size = size; >> + >> + raw_spin_lock_init(&qs->lock); >> + >> + return &qs->map; >> +} >> + >> +/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ >> +static void queue_stack_map_free(struct bpf_map *map) >> +{ >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); >> + >> + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, >> + * so the programs (can be more than one that used this map) were >> + * disconnected from events. Wait for outstanding critical sections in >> + * these programs to complete >> + */ >> + synchronize_rcu(); >> + >> + bpf_map_area_free(qs); >> +} >> + >> +static int __queue_map_get(struct bpf_map *map, void *value, bool delete) >> +{ >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); >> + unsigned long flags; >> + int err = 0; >> + void *ptr; >> + >> + raw_spin_lock_irqsave(&qs->lock, flags); >> + >> + if (queue_stack_map_is_empty(qs)) { >> + err = -ENOENT; >> + goto out; >> + } >> + >> + ptr = &qs->elements[qs->tail * qs->map.value_size]; >> + memcpy(value, ptr, qs->map.value_size); >> + >> + if (delete) { >> + if (unlikely(++qs->tail >= qs->size)) >> + qs->tail = 0; >> + } >> + >> +out: >> + raw_spin_unlock_irqrestore(&qs->lock, flags); >> + return err; >> +} >> + >> + >> +static int __stack_map_get(struct bpf_map *map, void *value, bool delete) >> +{ >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); >> + unsigned long flags; >> + int err = 0; >> + void *ptr; >> + u32 index; >> + >> + raw_spin_lock_irqsave(&qs->lock, flags); >> + >> + if (queue_stack_map_is_empty(qs)) { >> + err = -ENOENT; >> + goto out; >> + } >> + >> + index = qs->head - 1; >> + if (unlikely(index >= qs->size)) >> + index = qs->size - 1; >> + >> + ptr = &qs->elements[index * qs->map.value_size]; >> + memcpy(value, ptr, qs->map.value_size); >> + >> + if (delete) >> + qs->head = index; >> + >> +out: >> + raw_spin_unlock_irqrestore(&qs->lock, flags); >> + return err; >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int queue_map_peek_elem(struct bpf_map *map, void *value) >> +{ >> + return __queue_map_get(map, value, false); >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int stack_map_peek_elem(struct bpf_map *map, void *value) >> +{ >> + return __stack_map_get(map, value, false); >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int queue_map_pop_elem(struct bpf_map *map, void *value) >> +{ >> + return __queue_map_get(map, value, true); >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int stack_map_pop_elem(struct bpf_map *map, void *value) >> +{ >> + return __stack_map_get(map, value, true); >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int queue_stack_map_push_elem(struct bpf_map *map, void *value, >> + u64 flags) >> +{ >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); >> + unsigned long irq_flags; >> + int err = 0; >> + void *dst; >> + >> + /* BPF_EXIST is used to force making room for a new element in case the >> + * map is full >> + */ >> + bool replace = (flags & BPF_EXIST); >> + >> + /* Check supported flags for queue and stack maps */ >> + if (flags & BPF_NOEXIST || flags > BPF_EXIST) >> + return -EINVAL; >> + >> + raw_spin_lock_irqsave(&qs->lock, irq_flags); >> + >> + if (queue_stack_map_is_full(qs)) { >> + if (!replace) { >> + err = -E2BIG; >> + goto out; >> + } >> + /* advance tail pointer to overwrite oldest element */ >> + if (unlikely(++qs->tail >= qs->size)) >> + qs->tail = 0; >> + } >> + >> + dst = &qs->elements[qs->head * qs->map.value_size]; >> + memcpy(dst, value, qs->map.value_size); >> + >> + if (unlikely(++qs->head >= qs->size)) >> + qs->head = 0; >> + >> +out: >> + raw_spin_unlock_irqrestore(&qs->lock, irq_flags); >> + return err; >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key) >> +{ >> + return NULL; >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int queue_stack_map_update_elem(struct bpf_map *map, void *key, >> + void *value, u64 flags) >> +{ >> + return -EINVAL; >> +} >> + >> +/* Called from syscall or from eBPF program */ >> +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) >> +{ >> + return -EINVAL; >> +} >> + >> +/* Called from syscall */ >> +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, >> + void *next_key) >> +{ >> + return -EINVAL; >> +} >> + >> +const struct bpf_map_ops queue_map_ops = { >> + .map_alloc_check = queue_stack_map_alloc_check, >> + .map_alloc = queue_stack_map_alloc, >> + .map_free = queue_stack_map_free, >> + .map_lookup_elem = queue_stack_map_lookup_elem, >> + .map_update_elem = queue_stack_map_update_elem, >> + .map_delete_elem = queue_stack_map_delete_elem, >> + .map_push_elem = queue_stack_map_push_elem, >> + .map_pop_elem = queue_map_pop_elem, >> + .map_peek_elem = queue_map_peek_elem, >> + .map_get_next_key = queue_stack_map_get_next_key, >> +}; >> + >> +const struct bpf_map_ops stack_map_ops = { >> + .map_alloc_check = queue_stack_map_alloc_check, >> + .map_alloc = queue_stack_map_alloc, >> + .map_free = queue_stack_map_free, >> + .map_lookup_elem = queue_stack_map_lookup_elem, >> + .map_update_elem = queue_stack_map_update_elem, >> + .map_delete_elem = queue_stack_map_delete_elem, >> + .map_push_elem = queue_stack_map_push_elem, >> + .map_pop_elem = stack_map_pop_elem, >> + .map_peek_elem = stack_map_peek_elem, >> + .map_get_next_key = queue_stack_map_get_next_key, >> +}; >> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c >> index c33d9303f72f..c135d205fd09 100644 >> --- a/kernel/bpf/syscall.c >> +++ b/kernel/bpf/syscall.c >> @@ -727,6 +727,9 @@ static int map_lookup_elem(union bpf_attr *attr) >> err = bpf_fd_htab_map_lookup_elem(map, key, value); >> } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) { >> err = bpf_fd_reuseport_array_lookup_elem(map, key, value); >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || >> + map->map_type == BPF_MAP_TYPE_STACK) { >> + err = map->ops->map_peek_elem(map, value); >> } else { >> rcu_read_lock(); >> ptr = map->ops->map_lookup_elem(map, key); >> @@ -841,6 +844,9 @@ static int map_update_elem(union bpf_attr *attr) >> /* rcu_read_lock() is not needed */ >> err = bpf_fd_reuseport_array_update_elem(map, key, value, >> attr->flags); >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || >> + map->map_type == BPF_MAP_TYPE_STACK) { >> + err = map->ops->map_push_elem(map, value, attr->flags); >> } else { >> rcu_read_lock(); >> err = map->ops->map_update_elem(map, key, value, attr->flags); >> @@ -1023,16 +1029,22 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) >> */ >> preempt_disable(); >> __this_cpu_inc(bpf_prog_active); >> - if (!map->ops->map_lookup_and_delete_elem) { >> - err = -ENOTSUPP; >> - goto free_value; >> + if (map->map_type == BPF_MAP_TYPE_QUEUE || >> + map->map_type == BPF_MAP_TYPE_STACK) { >> + err = map->ops->map_pop_elem(map, value); >> + } else { >> + if (!map->ops->map_lookup_and_delete_elem) { >> + err = -ENOTSUPP; >> + goto free_value; > similar to previous patch: either we move this check, or we add > __this_cpu_dec() and preempt_enable(). In this case the check cannot be moved, I'll change it to fix the problem and make it more readable. > > Thanks, > Song >
On Tue, Oct 9, 2018 at 6:05 AM Mauricio Vasquez <mauricio.vasquez@polito.it> wrote: > > > > On 10/08/2018 08:36 PM, Song Liu wrote: > > On Mon, Oct 8, 2018 at 12:12 PM Mauricio Vasquez B > > <mauricio.vasquez@polito.it> wrote: > >> Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs. > >> These maps support peek, pop and push operations that are exposed to eBPF > >> programs through the new bpf_map[peek/pop/push] helpers. Those operations > >> are exposed to userspace applications through the already existing > >> syscalls in the following way: > >> > >> BPF_MAP_LOOKUP_ELEM -> peek > >> BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop > >> BPF_MAP_UPDATE_ELEM -> push > >> > >> Queue/stack maps are implemented using a buffer, tail and head indexes, > >> hence BPF_F_NO_PREALLOC is not supported. > >> > >> As opposite to other maps, queue and stack do not use RCU for protecting > >> maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE > >> argument that is a pointer to a memory zone where to save the value of a > >> map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not > >> be passed as an extra argument. > >> > >> Our main motivation for implementing queue/stack maps was to keep track > >> of a pool of elements, like network ports in a SNAT, however we forsee > >> other use cases, like for exampling saving last N kernel events in a map > >> and then analysing from userspace. > >> > >> Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it> > >> --- > >> include/linux/bpf.h | 7 + > >> include/linux/bpf_types.h | 2 > >> include/uapi/linux/bpf.h | 35 ++++- > >> kernel/bpf/Makefile | 2 > >> kernel/bpf/core.c | 3 > >> kernel/bpf/helpers.c | 43 ++++++ > >> kernel/bpf/queue_stack_maps.c | 288 +++++++++++++++++++++++++++++++++++++++++ > >> kernel/bpf/syscall.c | 30 +++- > >> kernel/bpf/verifier.c | 28 +++- > >> net/core/filter.c | 6 + > >> 10 files changed, 426 insertions(+), 18 deletions(-) > >> create mode 100644 kernel/bpf/queue_stack_maps.c > >> > >> diff --git a/include/linux/bpf.h b/include/linux/bpf.h > >> index 98c7eeb6d138..cad3bc5cffd1 100644 > >> --- a/include/linux/bpf.h > >> +++ b/include/linux/bpf.h > >> @@ -40,6 +40,9 @@ struct bpf_map_ops { > >> int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); > >> int (*map_delete_elem)(struct bpf_map *map, void *key); > >> void *(*map_lookup_and_delete_elem)(struct bpf_map *map, void *key); > >> + int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags); > >> + int (*map_pop_elem)(struct bpf_map *map, void *value); > >> + int (*map_peek_elem)(struct bpf_map *map, void *value); > >> > >> /* funcs called by prog_array and perf_event_array map */ > >> void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, > >> @@ -139,6 +142,7 @@ enum bpf_arg_type { > >> ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ > >> ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ > >> ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ > >> + ARG_PTR_TO_UNINIT_MAP_VALUE, /* pointer to valid memory used to store a map value */ > > How about we put ARG_PTR_TO_UNINIT_MAP_VALUE and related logic to a > > separate patch? > > I thought it too, but this is a really small change (6 additions, 3 > deletions). Does it worth a separated patch? I think a separate patch is better. You can also put small changes in uapi header in a separate patch. Thanks, Song > > > >> /* the following constraints used to prototype bpf_memcmp() and other > >> * functions that access data on eBPF program stack > >> @@ -825,6 +829,9 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, > >> extern const struct bpf_func_proto bpf_map_lookup_elem_proto; > >> extern const struct bpf_func_proto bpf_map_update_elem_proto; > >> extern const struct bpf_func_proto bpf_map_delete_elem_proto; > >> +extern const struct bpf_func_proto bpf_map_push_elem_proto; > >> +extern const struct bpf_func_proto bpf_map_pop_elem_proto; > >> +extern const struct bpf_func_proto bpf_map_peek_elem_proto; > >> > >> extern const struct bpf_func_proto bpf_get_prandom_u32_proto; > >> extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; > >> diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h > >> index 658509daacd4..a2ec73aa1ec7 100644 > >> --- a/include/linux/bpf_types.h > >> +++ b/include/linux/bpf_types.h > >> @@ -69,3 +69,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) > >> BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) > >> #endif > >> #endif > >> +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) > >> +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) > >> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > >> index 3bb94aa2d408..bfa042273fad 100644 > >> --- a/include/uapi/linux/bpf.h > >> +++ b/include/uapi/linux/bpf.h > >> @@ -129,6 +129,8 @@ enum bpf_map_type { > >> BPF_MAP_TYPE_CGROUP_STORAGE, > >> BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, > >> BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, > >> + BPF_MAP_TYPE_QUEUE, > >> + BPF_MAP_TYPE_STACK, > >> }; > >> > >> enum bpf_prog_type { > >> @@ -463,6 +465,28 @@ union bpf_attr { > >> * Return > >> * 0 on success, or a negative error in case of failure. > >> * > >> + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) > >> + * Description > >> + * Push an element *value* in *map*. *flags* is one of: > >> + * > >> + * **BPF_EXIST** > >> + * If the queue/stack is full, the oldest element is removed to > >> + * make room for this. > >> + * Return > >> + * 0 on success, or a negative error in case of failure. > >> + * > >> + * int bpf_map_pop_elem(struct bpf_map *map, void *value) > >> + * Description > >> + * Pop an element from *map*. > >> + * Return > >> + * 0 on success, or a negative error in case of failure. > >> + * > >> + * int bpf_map_peek_elem(struct bpf_map *map, void *value) > >> + * Description > >> + * Get an element from *map* without removing it. > >> + * Return > >> + * 0 on success, or a negative error in case of failure. > >> + * > >> * int bpf_probe_read(void *dst, u32 size, const void *src) > >> * Description > >> * For tracing programs, safely attempt to read *size* bytes from > >> @@ -790,14 +814,14 @@ union bpf_attr { > >> * > >> * int ret; > >> * struct bpf_tunnel_key key = {}; > >> - * > >> + * > >> * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0); > >> * if (ret < 0) > >> * return TC_ACT_SHOT; // drop packet > >> - * > >> + * > >> * if (key.remote_ipv4 != 0x0a000001) > >> * return TC_ACT_SHOT; // drop packet > >> - * > >> + * > >> * return TC_ACT_OK; // accept packet > >> * > >> * This interface can also be used with all encapsulation devices > >> @@ -2304,7 +2328,10 @@ union bpf_attr { > >> FN(skb_ancestor_cgroup_id), \ > >> FN(sk_lookup_tcp), \ > >> FN(sk_lookup_udp), \ > >> - FN(sk_release), > >> + FN(sk_release), \ > >> + FN(map_push_elem), \ > >> + FN(map_pop_elem), \ > >> + FN(map_peek_elem), > >> > >> /* integer value in 'imm' field of BPF_CALL instruction selects which helper > >> * function eBPF program intends to call > >> diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile > >> index 0488b8258321..17afae9e65f3 100644 > >> --- a/kernel/bpf/Makefile > >> +++ b/kernel/bpf/Makefile > >> @@ -3,7 +3,7 @@ obj-y := core.o > >> > >> obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o > >> obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o > >> -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o > >> +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o > >> obj-$(CONFIG_BPF_SYSCALL) += disasm.o > >> obj-$(CONFIG_BPF_SYSCALL) += btf.o > >> ifeq ($(CONFIG_NET),y) > >> diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c > >> index 3f5bf1af0826..8d2db076d123 100644 > >> --- a/kernel/bpf/core.c > >> +++ b/kernel/bpf/core.c > >> @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) > >> const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; > >> const struct bpf_func_proto bpf_map_update_elem_proto __weak; > >> const struct bpf_func_proto bpf_map_delete_elem_proto __weak; > >> +const struct bpf_func_proto bpf_map_push_elem_proto __weak; > >> +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; > >> +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; > >> > >> const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; > >> const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; > >> diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c > >> index 6502115e8f55..ab0d5e3f9892 100644 > >> --- a/kernel/bpf/helpers.c > >> +++ b/kernel/bpf/helpers.c > >> @@ -76,6 +76,49 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { > >> .arg2_type = ARG_PTR_TO_MAP_KEY, > >> }; > >> > >> +BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags) > >> +{ > >> + return map->ops->map_push_elem(map, value, flags); > >> +} > >> + > >> +const struct bpf_func_proto bpf_map_push_elem_proto = { > >> + .func = bpf_map_push_elem, > >> + .gpl_only = false, > >> + .pkt_access = true, > >> + .ret_type = RET_INTEGER, > >> + .arg1_type = ARG_CONST_MAP_PTR, > >> + .arg2_type = ARG_PTR_TO_MAP_VALUE, > >> + .arg3_type = ARG_ANYTHING, > >> +}; > >> + > >> +BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value) > >> +{ > >> + return map->ops->map_pop_elem(map, value); > >> +} > >> + > >> +const struct bpf_func_proto bpf_map_pop_elem_proto = { > >> + .func = bpf_map_pop_elem, > >> + .gpl_only = false, > >> + .pkt_access = true, > >> + .ret_type = RET_INTEGER, > >> + .arg1_type = ARG_CONST_MAP_PTR, > >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, > >> +}; > >> + > >> +BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value) > >> +{ > >> + return map->ops->map_peek_elem(map, value); > >> +} > >> + > >> +const struct bpf_func_proto bpf_map_peek_elem_proto = { > >> + .func = bpf_map_pop_elem, > >> + .gpl_only = false, > >> + .pkt_access = true, > >> + .ret_type = RET_INTEGER, > >> + .arg1_type = ARG_CONST_MAP_PTR, > >> + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, > >> +}; > >> + > >> const struct bpf_func_proto bpf_get_prandom_u32_proto = { > >> .func = bpf_user_rnd_u32, > >> .gpl_only = false, > >> diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c > >> new file mode 100644 > >> index 000000000000..12a93fb37449 > >> --- /dev/null > >> +++ b/kernel/bpf/queue_stack_maps.c > >> @@ -0,0 +1,288 @@ > >> +// SPDX-License-Identifier: GPL-2.0 > >> +/* > >> + * queue_stack_maps.c: BPF queue and stack maps > >> + * > >> + * Copyright (c) 2018 Politecnico di Torino > >> + */ > >> +#include <linux/bpf.h> > >> +#include <linux/list.h> > >> +#include <linux/slab.h> > >> +#include "percpu_freelist.h" > >> + > >> +#define QUEUE_STACK_CREATE_FLAG_MASK \ > >> + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) > >> + > >> + > >> +struct bpf_queue_stack { > >> + struct bpf_map map; > >> + raw_spinlock_t lock; > >> + u32 head, tail; > >> + u32 size; /* max_entries + 1 */ > >> + > >> + char elements[0] __aligned(8); > >> +}; > >> + > >> +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) > >> +{ > >> + return container_of(map, struct bpf_queue_stack, map); > >> +} > >> + > >> +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) > >> +{ > >> + return qs->head == qs->tail; > >> +} > >> + > >> +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) > >> +{ > >> + u32 head = qs->head + 1; > >> + > >> + if (unlikely(head >= qs->size)) > >> + head = 0; > >> + > >> + return head == qs->tail; > >> +} > >> + > >> +/* Called from syscall */ > >> +static int queue_stack_map_alloc_check(union bpf_attr *attr) > >> +{ > >> + /* check sanity of attributes */ > >> + if (attr->max_entries == 0 || attr->key_size != 0 || > >> + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK) > >> + return -EINVAL; > >> + > >> + if (attr->value_size > KMALLOC_MAX_SIZE) > >> + /* if value_size is bigger, the user space won't be able to > >> + * access the elements. > >> + */ > >> + return -E2BIG; > >> + > >> + return 0; > >> +} > >> + > >> +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) > >> +{ > >> + int ret, numa_node = bpf_map_attr_numa_node(attr); > >> + struct bpf_queue_stack *qs; > >> + u32 size, value_size; > >> + u64 queue_size, cost; > >> + > >> + size = attr->max_entries + 1; > >> + value_size = attr->value_size; > >> + > >> + queue_size = sizeof(*qs) + (u64) value_size * size; > >> + > >> + cost = queue_size; > >> + if (cost >= U32_MAX - PAGE_SIZE) > >> + return ERR_PTR(-E2BIG); > >> + > >> + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; > >> + > >> + ret = bpf_map_precharge_memlock(cost); > >> + if (ret < 0) > >> + return ERR_PTR(ret); > >> + > >> + qs = bpf_map_area_alloc(queue_size, numa_node); > >> + if (!qs) > >> + return ERR_PTR(-ENOMEM); > >> + > >> + memset(qs, 0, sizeof(*qs)); > >> + > >> + bpf_map_init_from_attr(&qs->map, attr); > >> + > >> + qs->map.pages = cost; > >> + qs->size = size; > >> + > >> + raw_spin_lock_init(&qs->lock); > >> + > >> + return &qs->map; > >> +} > >> + > >> +/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ > >> +static void queue_stack_map_free(struct bpf_map *map) > >> +{ > >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); > >> + > >> + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, > >> + * so the programs (can be more than one that used this map) were > >> + * disconnected from events. Wait for outstanding critical sections in > >> + * these programs to complete > >> + */ > >> + synchronize_rcu(); > >> + > >> + bpf_map_area_free(qs); > >> +} > >> + > >> +static int __queue_map_get(struct bpf_map *map, void *value, bool delete) > >> +{ > >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); > >> + unsigned long flags; > >> + int err = 0; > >> + void *ptr; > >> + > >> + raw_spin_lock_irqsave(&qs->lock, flags); > >> + > >> + if (queue_stack_map_is_empty(qs)) { > >> + err = -ENOENT; > >> + goto out; > >> + } > >> + > >> + ptr = &qs->elements[qs->tail * qs->map.value_size]; > >> + memcpy(value, ptr, qs->map.value_size); > >> + > >> + if (delete) { > >> + if (unlikely(++qs->tail >= qs->size)) > >> + qs->tail = 0; > >> + } > >> + > >> +out: > >> + raw_spin_unlock_irqrestore(&qs->lock, flags); > >> + return err; > >> +} > >> + > >> + > >> +static int __stack_map_get(struct bpf_map *map, void *value, bool delete) > >> +{ > >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); > >> + unsigned long flags; > >> + int err = 0; > >> + void *ptr; > >> + u32 index; > >> + > >> + raw_spin_lock_irqsave(&qs->lock, flags); > >> + > >> + if (queue_stack_map_is_empty(qs)) { > >> + err = -ENOENT; > >> + goto out; > >> + } > >> + > >> + index = qs->head - 1; > >> + if (unlikely(index >= qs->size)) > >> + index = qs->size - 1; > >> + > >> + ptr = &qs->elements[index * qs->map.value_size]; > >> + memcpy(value, ptr, qs->map.value_size); > >> + > >> + if (delete) > >> + qs->head = index; > >> + > >> +out: > >> + raw_spin_unlock_irqrestore(&qs->lock, flags); > >> + return err; > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int queue_map_peek_elem(struct bpf_map *map, void *value) > >> +{ > >> + return __queue_map_get(map, value, false); > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int stack_map_peek_elem(struct bpf_map *map, void *value) > >> +{ > >> + return __stack_map_get(map, value, false); > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int queue_map_pop_elem(struct bpf_map *map, void *value) > >> +{ > >> + return __queue_map_get(map, value, true); > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int stack_map_pop_elem(struct bpf_map *map, void *value) > >> +{ > >> + return __stack_map_get(map, value, true); > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int queue_stack_map_push_elem(struct bpf_map *map, void *value, > >> + u64 flags) > >> +{ > >> + struct bpf_queue_stack *qs = bpf_queue_stack(map); > >> + unsigned long irq_flags; > >> + int err = 0; > >> + void *dst; > >> + > >> + /* BPF_EXIST is used to force making room for a new element in case the > >> + * map is full > >> + */ > >> + bool replace = (flags & BPF_EXIST); > >> + > >> + /* Check supported flags for queue and stack maps */ > >> + if (flags & BPF_NOEXIST || flags > BPF_EXIST) > >> + return -EINVAL; > >> + > >> + raw_spin_lock_irqsave(&qs->lock, irq_flags); > >> + > >> + if (queue_stack_map_is_full(qs)) { > >> + if (!replace) { > >> + err = -E2BIG; > >> + goto out; > >> + } > >> + /* advance tail pointer to overwrite oldest element */ > >> + if (unlikely(++qs->tail >= qs->size)) > >> + qs->tail = 0; > >> + } > >> + > >> + dst = &qs->elements[qs->head * qs->map.value_size]; > >> + memcpy(dst, value, qs->map.value_size); > >> + > >> + if (unlikely(++qs->head >= qs->size)) > >> + qs->head = 0; > >> + > >> +out: > >> + raw_spin_unlock_irqrestore(&qs->lock, irq_flags); > >> + return err; > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key) > >> +{ > >> + return NULL; > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int queue_stack_map_update_elem(struct bpf_map *map, void *key, > >> + void *value, u64 flags) > >> +{ > >> + return -EINVAL; > >> +} > >> + > >> +/* Called from syscall or from eBPF program */ > >> +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) > >> +{ > >> + return -EINVAL; > >> +} > >> + > >> +/* Called from syscall */ > >> +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, > >> + void *next_key) > >> +{ > >> + return -EINVAL; > >> +} > >> + > >> +const struct bpf_map_ops queue_map_ops = { > >> + .map_alloc_check = queue_stack_map_alloc_check, > >> + .map_alloc = queue_stack_map_alloc, > >> + .map_free = queue_stack_map_free, > >> + .map_lookup_elem = queue_stack_map_lookup_elem, > >> + .map_update_elem = queue_stack_map_update_elem, > >> + .map_delete_elem = queue_stack_map_delete_elem, > >> + .map_push_elem = queue_stack_map_push_elem, > >> + .map_pop_elem = queue_map_pop_elem, > >> + .map_peek_elem = queue_map_peek_elem, > >> + .map_get_next_key = queue_stack_map_get_next_key, > >> +}; > >> + > >> +const struct bpf_map_ops stack_map_ops = { > >> + .map_alloc_check = queue_stack_map_alloc_check, > >> + .map_alloc = queue_stack_map_alloc, > >> + .map_free = queue_stack_map_free, > >> + .map_lookup_elem = queue_stack_map_lookup_elem, > >> + .map_update_elem = queue_stack_map_update_elem, > >> + .map_delete_elem = queue_stack_map_delete_elem, > >> + .map_push_elem = queue_stack_map_push_elem, > >> + .map_pop_elem = stack_map_pop_elem, > >> + .map_peek_elem = stack_map_peek_elem, > >> + .map_get_next_key = queue_stack_map_get_next_key, > >> +}; > >> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > >> index c33d9303f72f..c135d205fd09 100644 > >> --- a/kernel/bpf/syscall.c > >> +++ b/kernel/bpf/syscall.c > >> @@ -727,6 +727,9 @@ static int map_lookup_elem(union bpf_attr *attr) > >> err = bpf_fd_htab_map_lookup_elem(map, key, value); > >> } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) { > >> err = bpf_fd_reuseport_array_lookup_elem(map, key, value); > >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || > >> + map->map_type == BPF_MAP_TYPE_STACK) { > >> + err = map->ops->map_peek_elem(map, value); > >> } else { > >> rcu_read_lock(); > >> ptr = map->ops->map_lookup_elem(map, key); > >> @@ -841,6 +844,9 @@ static int map_update_elem(union bpf_attr *attr) > >> /* rcu_read_lock() is not needed */ > >> err = bpf_fd_reuseport_array_update_elem(map, key, value, > >> attr->flags); > >> + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || > >> + map->map_type == BPF_MAP_TYPE_STACK) { > >> + err = map->ops->map_push_elem(map, value, attr->flags); > >> } else { > >> rcu_read_lock(); > >> err = map->ops->map_update_elem(map, key, value, attr->flags); > >> @@ -1023,16 +1029,22 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) > >> */ > >> preempt_disable(); > >> __this_cpu_inc(bpf_prog_active); > >> - if (!map->ops->map_lookup_and_delete_elem) { > >> - err = -ENOTSUPP; > >> - goto free_value; > >> + if (map->map_type == BPF_MAP_TYPE_QUEUE || > >> + map->map_type == BPF_MAP_TYPE_STACK) { > >> + err = map->ops->map_pop_elem(map, value); > >> + } else { > >> + if (!map->ops->map_lookup_and_delete_elem) { > >> + err = -ENOTSUPP; > >> + goto free_value; > > similar to previous patch: either we move this check, or we add > > __this_cpu_dec() and preempt_enable(). > > In this case the check cannot be moved, I'll change it to fix the > problem and make it more readable. > > > > > Thanks, > > Song > > >
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 98c7eeb6d138..cad3bc5cffd1 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -40,6 +40,9 @@ struct bpf_map_ops { int (*map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags); int (*map_delete_elem)(struct bpf_map *map, void *key); void *(*map_lookup_and_delete_elem)(struct bpf_map *map, void *key); + int (*map_push_elem)(struct bpf_map *map, void *value, u64 flags); + int (*map_pop_elem)(struct bpf_map *map, void *value); + int (*map_peek_elem)(struct bpf_map *map, void *value); /* funcs called by prog_array and perf_event_array map */ void *(*map_fd_get_ptr)(struct bpf_map *map, struct file *map_file, @@ -139,6 +142,7 @@ enum bpf_arg_type { ARG_CONST_MAP_PTR, /* const argument used as pointer to bpf_map */ ARG_PTR_TO_MAP_KEY, /* pointer to stack used as map key */ ARG_PTR_TO_MAP_VALUE, /* pointer to stack used as map value */ + ARG_PTR_TO_UNINIT_MAP_VALUE, /* pointer to valid memory used to store a map value */ /* the following constraints used to prototype bpf_memcmp() and other * functions that access data on eBPF program stack @@ -825,6 +829,9 @@ static inline int bpf_fd_reuseport_array_update_elem(struct bpf_map *map, extern const struct bpf_func_proto bpf_map_lookup_elem_proto; extern const struct bpf_func_proto bpf_map_update_elem_proto; extern const struct bpf_func_proto bpf_map_delete_elem_proto; +extern const struct bpf_func_proto bpf_map_push_elem_proto; +extern const struct bpf_func_proto bpf_map_pop_elem_proto; +extern const struct bpf_func_proto bpf_map_peek_elem_proto; extern const struct bpf_func_proto bpf_get_prandom_u32_proto; extern const struct bpf_func_proto bpf_get_smp_processor_id_proto; diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 658509daacd4..a2ec73aa1ec7 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -69,3 +69,5 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, reuseport_array_ops) #endif #endif +BPF_MAP_TYPE(BPF_MAP_TYPE_QUEUE, queue_map_ops) +BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3bb94aa2d408..bfa042273fad 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -129,6 +129,8 @@ enum bpf_map_type { BPF_MAP_TYPE_CGROUP_STORAGE, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY, BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE, + BPF_MAP_TYPE_QUEUE, + BPF_MAP_TYPE_STACK, }; enum bpf_prog_type { @@ -463,6 +465,28 @@ union bpf_attr { * Return * 0 on success, or a negative error in case of failure. * + * int bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) + * Description + * Push an element *value* in *map*. *flags* is one of: + * + * **BPF_EXIST** + * If the queue/stack is full, the oldest element is removed to + * make room for this. + * Return + * 0 on success, or a negative error in case of failure. + * + * int bpf_map_pop_elem(struct bpf_map *map, void *value) + * Description + * Pop an element from *map*. + * Return + * 0 on success, or a negative error in case of failure. + * + * int bpf_map_peek_elem(struct bpf_map *map, void *value) + * Description + * Get an element from *map* without removing it. + * Return + * 0 on success, or a negative error in case of failure. + * * int bpf_probe_read(void *dst, u32 size, const void *src) * Description * For tracing programs, safely attempt to read *size* bytes from @@ -790,14 +814,14 @@ union bpf_attr { * * int ret; * struct bpf_tunnel_key key = {}; - * + * * ret = bpf_skb_get_tunnel_key(skb, &key, sizeof(key), 0); * if (ret < 0) * return TC_ACT_SHOT; // drop packet - * + * * if (key.remote_ipv4 != 0x0a000001) * return TC_ACT_SHOT; // drop packet - * + * * return TC_ACT_OK; // accept packet * * This interface can also be used with all encapsulation devices @@ -2304,7 +2328,10 @@ union bpf_attr { FN(skb_ancestor_cgroup_id), \ FN(sk_lookup_tcp), \ FN(sk_lookup_udp), \ - FN(sk_release), + FN(sk_release), \ + FN(map_push_elem), \ + FN(map_pop_elem), \ + FN(map_peek_elem), /* integer value in 'imm' field of BPF_CALL instruction selects which helper * function eBPF program intends to call diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 0488b8258321..17afae9e65f3 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -3,7 +3,7 @@ obj-y := core.o obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o -obj-$(CONFIG_BPF_SYSCALL) += local_storage.o +obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o obj-$(CONFIG_BPF_SYSCALL) += disasm.o obj-$(CONFIG_BPF_SYSCALL) += btf.o ifeq ($(CONFIG_NET),y) diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 3f5bf1af0826..8d2db076d123 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1783,6 +1783,9 @@ BPF_CALL_0(bpf_user_rnd_u32) const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; const struct bpf_func_proto bpf_map_update_elem_proto __weak; const struct bpf_func_proto bpf_map_delete_elem_proto __weak; +const struct bpf_func_proto bpf_map_push_elem_proto __weak; +const struct bpf_func_proto bpf_map_pop_elem_proto __weak; +const struct bpf_func_proto bpf_map_peek_elem_proto __weak; const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 6502115e8f55..ab0d5e3f9892 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -76,6 +76,49 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { .arg2_type = ARG_PTR_TO_MAP_KEY, }; +BPF_CALL_3(bpf_map_push_elem, struct bpf_map *, map, void *, value, u64, flags) +{ + return map->ops->map_push_elem(map, value, flags); +} + +const struct bpf_func_proto bpf_map_push_elem_proto = { + .func = bpf_map_push_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_MAP_VALUE, + .arg3_type = ARG_ANYTHING, +}; + +BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, value) +{ + return map->ops->map_pop_elem(map, value); +} + +const struct bpf_func_proto bpf_map_pop_elem_proto = { + .func = bpf_map_pop_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, +}; + +BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void *, value) +{ + return map->ops->map_peek_elem(map, value); +} + +const struct bpf_func_proto bpf_map_peek_elem_proto = { + .func = bpf_map_pop_elem, + .gpl_only = false, + .pkt_access = true, + .ret_type = RET_INTEGER, + .arg1_type = ARG_CONST_MAP_PTR, + .arg2_type = ARG_PTR_TO_UNINIT_MAP_VALUE, +}; + const struct bpf_func_proto bpf_get_prandom_u32_proto = { .func = bpf_user_rnd_u32, .gpl_only = false, diff --git a/kernel/bpf/queue_stack_maps.c b/kernel/bpf/queue_stack_maps.c new file mode 100644 index 000000000000..12a93fb37449 --- /dev/null +++ b/kernel/bpf/queue_stack_maps.c @@ -0,0 +1,288 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * queue_stack_maps.c: BPF queue and stack maps + * + * Copyright (c) 2018 Politecnico di Torino + */ +#include <linux/bpf.h> +#include <linux/list.h> +#include <linux/slab.h> +#include "percpu_freelist.h" + +#define QUEUE_STACK_CREATE_FLAG_MASK \ + (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY) + + +struct bpf_queue_stack { + struct bpf_map map; + raw_spinlock_t lock; + u32 head, tail; + u32 size; /* max_entries + 1 */ + + char elements[0] __aligned(8); +}; + +static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) +{ + return container_of(map, struct bpf_queue_stack, map); +} + +static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) +{ + return qs->head == qs->tail; +} + +static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) +{ + u32 head = qs->head + 1; + + if (unlikely(head >= qs->size)) + head = 0; + + return head == qs->tail; +} + +/* Called from syscall */ +static int queue_stack_map_alloc_check(union bpf_attr *attr) +{ + /* check sanity of attributes */ + if (attr->max_entries == 0 || attr->key_size != 0 || + attr->map_flags & ~QUEUE_STACK_CREATE_FLAG_MASK) + return -EINVAL; + + if (attr->value_size > KMALLOC_MAX_SIZE) + /* if value_size is bigger, the user space won't be able to + * access the elements. + */ + return -E2BIG; + + return 0; +} + +static struct bpf_map *queue_stack_map_alloc(union bpf_attr *attr) +{ + int ret, numa_node = bpf_map_attr_numa_node(attr); + struct bpf_queue_stack *qs; + u32 size, value_size; + u64 queue_size, cost; + + size = attr->max_entries + 1; + value_size = attr->value_size; + + queue_size = sizeof(*qs) + (u64) value_size * size; + + cost = queue_size; + if (cost >= U32_MAX - PAGE_SIZE) + return ERR_PTR(-E2BIG); + + cost = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT; + + ret = bpf_map_precharge_memlock(cost); + if (ret < 0) + return ERR_PTR(ret); + + qs = bpf_map_area_alloc(queue_size, numa_node); + if (!qs) + return ERR_PTR(-ENOMEM); + + memset(qs, 0, sizeof(*qs)); + + bpf_map_init_from_attr(&qs->map, attr); + + qs->map.pages = cost; + qs->size = size; + + raw_spin_lock_init(&qs->lock); + + return &qs->map; +} + +/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ +static void queue_stack_map_free(struct bpf_map *map) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + + /* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0, + * so the programs (can be more than one that used this map) were + * disconnected from events. Wait for outstanding critical sections in + * these programs to complete + */ + synchronize_rcu(); + + bpf_map_area_free(qs); +} + +static int __queue_map_get(struct bpf_map *map, void *value, bool delete) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long flags; + int err = 0; + void *ptr; + + raw_spin_lock_irqsave(&qs->lock, flags); + + if (queue_stack_map_is_empty(qs)) { + err = -ENOENT; + goto out; + } + + ptr = &qs->elements[qs->tail * qs->map.value_size]; + memcpy(value, ptr, qs->map.value_size); + + if (delete) { + if (unlikely(++qs->tail >= qs->size)) + qs->tail = 0; + } + +out: + raw_spin_unlock_irqrestore(&qs->lock, flags); + return err; +} + + +static int __stack_map_get(struct bpf_map *map, void *value, bool delete) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long flags; + int err = 0; + void *ptr; + u32 index; + + raw_spin_lock_irqsave(&qs->lock, flags); + + if (queue_stack_map_is_empty(qs)) { + err = -ENOENT; + goto out; + } + + index = qs->head - 1; + if (unlikely(index >= qs->size)) + index = qs->size - 1; + + ptr = &qs->elements[index * qs->map.value_size]; + memcpy(value, ptr, qs->map.value_size); + + if (delete) + qs->head = index; + +out: + raw_spin_unlock_irqrestore(&qs->lock, flags); + return err; +} + +/* Called from syscall or from eBPF program */ +static int queue_map_peek_elem(struct bpf_map *map, void *value) +{ + return __queue_map_get(map, value, false); +} + +/* Called from syscall or from eBPF program */ +static int stack_map_peek_elem(struct bpf_map *map, void *value) +{ + return __stack_map_get(map, value, false); +} + +/* Called from syscall or from eBPF program */ +static int queue_map_pop_elem(struct bpf_map *map, void *value) +{ + return __queue_map_get(map, value, true); +} + +/* Called from syscall or from eBPF program */ +static int stack_map_pop_elem(struct bpf_map *map, void *value) +{ + return __stack_map_get(map, value, true); +} + +/* Called from syscall or from eBPF program */ +static int queue_stack_map_push_elem(struct bpf_map *map, void *value, + u64 flags) +{ + struct bpf_queue_stack *qs = bpf_queue_stack(map); + unsigned long irq_flags; + int err = 0; + void *dst; + + /* BPF_EXIST is used to force making room for a new element in case the + * map is full + */ + bool replace = (flags & BPF_EXIST); + + /* Check supported flags for queue and stack maps */ + if (flags & BPF_NOEXIST || flags > BPF_EXIST) + return -EINVAL; + + raw_spin_lock_irqsave(&qs->lock, irq_flags); + + if (queue_stack_map_is_full(qs)) { + if (!replace) { + err = -E2BIG; + goto out; + } + /* advance tail pointer to overwrite oldest element */ + if (unlikely(++qs->tail >= qs->size)) + qs->tail = 0; + } + + dst = &qs->elements[qs->head * qs->map.value_size]; + memcpy(dst, value, qs->map.value_size); + + if (unlikely(++qs->head >= qs->size)) + qs->head = 0; + +out: + raw_spin_unlock_irqrestore(&qs->lock, irq_flags); + return err; +} + +/* Called from syscall or from eBPF program */ +static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key) +{ + return NULL; +} + +/* Called from syscall or from eBPF program */ +static int queue_stack_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + return -EINVAL; +} + +/* Called from syscall or from eBPF program */ +static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) +{ + return -EINVAL; +} + +/* Called from syscall */ +static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, + void *next_key) +{ + return -EINVAL; +} + +const struct bpf_map_ops queue_map_ops = { + .map_alloc_check = queue_stack_map_alloc_check, + .map_alloc = queue_stack_map_alloc, + .map_free = queue_stack_map_free, + .map_lookup_elem = queue_stack_map_lookup_elem, + .map_update_elem = queue_stack_map_update_elem, + .map_delete_elem = queue_stack_map_delete_elem, + .map_push_elem = queue_stack_map_push_elem, + .map_pop_elem = queue_map_pop_elem, + .map_peek_elem = queue_map_peek_elem, + .map_get_next_key = queue_stack_map_get_next_key, +}; + +const struct bpf_map_ops stack_map_ops = { + .map_alloc_check = queue_stack_map_alloc_check, + .map_alloc = queue_stack_map_alloc, + .map_free = queue_stack_map_free, + .map_lookup_elem = queue_stack_map_lookup_elem, + .map_update_elem = queue_stack_map_update_elem, + .map_delete_elem = queue_stack_map_delete_elem, + .map_push_elem = queue_stack_map_push_elem, + .map_pop_elem = stack_map_pop_elem, + .map_peek_elem = stack_map_peek_elem, + .map_get_next_key = queue_stack_map_get_next_key, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index c33d9303f72f..c135d205fd09 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -727,6 +727,9 @@ static int map_lookup_elem(union bpf_attr *attr) err = bpf_fd_htab_map_lookup_elem(map, key, value); } else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) { err = bpf_fd_reuseport_array_lookup_elem(map, key, value); + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || + map->map_type == BPF_MAP_TYPE_STACK) { + err = map->ops->map_peek_elem(map, value); } else { rcu_read_lock(); ptr = map->ops->map_lookup_elem(map, key); @@ -841,6 +844,9 @@ static int map_update_elem(union bpf_attr *attr) /* rcu_read_lock() is not needed */ err = bpf_fd_reuseport_array_update_elem(map, key, value, attr->flags); + } else if (map->map_type == BPF_MAP_TYPE_QUEUE || + map->map_type == BPF_MAP_TYPE_STACK) { + err = map->ops->map_push_elem(map, value, attr->flags); } else { rcu_read_lock(); err = map->ops->map_update_elem(map, key, value, attr->flags); @@ -1023,16 +1029,22 @@ static int map_lookup_and_delete_elem(union bpf_attr *attr) */ preempt_disable(); __this_cpu_inc(bpf_prog_active); - if (!map->ops->map_lookup_and_delete_elem) { - err = -ENOTSUPP; - goto free_value; + if (map->map_type == BPF_MAP_TYPE_QUEUE || + map->map_type == BPF_MAP_TYPE_STACK) { + err = map->ops->map_pop_elem(map, value); + } else { + if (!map->ops->map_lookup_and_delete_elem) { + err = -ENOTSUPP; + goto free_value; + } + rcu_read_lock(); + ptr = map->ops->map_lookup_and_delete_elem(map, key); + if (ptr) + memcpy(value, ptr, value_size); + rcu_read_unlock(); + err = ptr ? 0 : -ENOENT; } - rcu_read_lock(); - ptr = map->ops->map_lookup_and_delete_elem(map, key); - if (ptr) - memcpy(value, ptr, value_size); - rcu_read_unlock(); - err = ptr ? 0 : -ENOENT; + __this_cpu_dec(bpf_prog_active); preempt_enable(); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 73c81bef6ae8..8b1f1b348782 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2121,7 +2121,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, } if (arg_type == ARG_PTR_TO_MAP_KEY || - arg_type == ARG_PTR_TO_MAP_VALUE) { + arg_type == ARG_PTR_TO_MAP_VALUE || + arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { expected_type = PTR_TO_STACK; if (!type_is_pkt_pointer(type) && type != PTR_TO_MAP_VALUE && type != expected_type) @@ -2191,7 +2192,8 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, err = check_helper_mem_access(env, regno, meta->map_ptr->key_size, false, NULL); - } else if (arg_type == ARG_PTR_TO_MAP_VALUE) { + } else if (arg_type == ARG_PTR_TO_MAP_VALUE || + arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE) { /* bpf_map_xxx(..., map_ptr, ..., value) call: * check [value, value + map->value_size) validity */ @@ -2200,9 +2202,10 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 regno, verbose(env, "invalid map_ptr to access map->value\n"); return -EACCES; } + meta->raw_mode = (arg_type == ARG_PTR_TO_UNINIT_MAP_VALUE); err = check_helper_mem_access(env, regno, meta->map_ptr->value_size, false, - NULL); + meta); } else if (arg_type_is_mem_size(arg_type)) { bool zero_size_allowed = (arg_type == ARG_CONST_SIZE_OR_ZERO); @@ -2325,6 +2328,13 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (func_id != BPF_FUNC_sk_select_reuseport) goto error; break; + case BPF_MAP_TYPE_QUEUE: + case BPF_MAP_TYPE_STACK: + if (func_id != BPF_FUNC_map_peek_elem && + func_id != BPF_FUNC_map_pop_elem && + func_id != BPF_FUNC_map_push_elem) + goto error; + break; default: break; } @@ -2381,6 +2391,13 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) goto error; break; + case BPF_FUNC_map_peek_elem: + case BPF_FUNC_map_pop_elem: + case BPF_FUNC_map_push_elem: + if (map->map_type != BPF_MAP_TYPE_QUEUE && + map->map_type != BPF_MAP_TYPE_STACK) + goto error; + break; default: break; } @@ -2676,7 +2693,10 @@ record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta, if (func_id != BPF_FUNC_tail_call && func_id != BPF_FUNC_map_lookup_elem && func_id != BPF_FUNC_map_update_elem && - func_id != BPF_FUNC_map_delete_elem) + func_id != BPF_FUNC_map_delete_elem && + func_id != BPF_FUNC_map_push_elem && + func_id != BPF_FUNC_map_pop_elem && + func_id != BPF_FUNC_map_peek_elem) return 0; if (meta->map_ptr == NULL) { diff --git a/net/core/filter.c b/net/core/filter.c index 591c698bc517..40736e0d9cff 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4993,6 +4993,12 @@ bpf_base_func_proto(enum bpf_func_id func_id) return &bpf_map_update_elem_proto; case BPF_FUNC_map_delete_elem: return &bpf_map_delete_elem_proto; + case BPF_FUNC_map_push_elem: + return &bpf_map_push_elem_proto; + case BPF_FUNC_map_pop_elem: + return &bpf_map_pop_elem_proto; + case BPF_FUNC_map_peek_elem: + return &bpf_map_peek_elem_proto; case BPF_FUNC_get_prandom_u32: return &bpf_get_prandom_u32_proto; case BPF_FUNC_get_smp_processor_id:
Queue/stack maps implement a FIFO/LIFO data storage for ebpf programs. These maps support peek, pop and push operations that are exposed to eBPF programs through the new bpf_map[peek/pop/push] helpers. Those operations are exposed to userspace applications through the already existing syscalls in the following way: BPF_MAP_LOOKUP_ELEM -> peek BPF_MAP_LOOKUP_AND_DELETE_ELEM -> pop BPF_MAP_UPDATE_ELEM -> push Queue/stack maps are implemented using a buffer, tail and head indexes, hence BPF_F_NO_PREALLOC is not supported. As opposite to other maps, queue and stack do not use RCU for protecting maps values, the bpf_map[peek/pop] have a ARG_PTR_TO_UNINIT_MAP_VALUE argument that is a pointer to a memory zone where to save the value of a map. Basically the same as ARG_PTR_TO_UNINIT_MEM, but the size has not be passed as an extra argument. Our main motivation for implementing queue/stack maps was to keep track of a pool of elements, like network ports in a SNAT, however we forsee other use cases, like for exampling saving last N kernel events in a map and then analysing from userspace. Signed-off-by: Mauricio Vasquez B <mauricio.vasquez@polito.it> --- include/linux/bpf.h | 7 + include/linux/bpf_types.h | 2 include/uapi/linux/bpf.h | 35 ++++- kernel/bpf/Makefile | 2 kernel/bpf/core.c | 3 kernel/bpf/helpers.c | 43 ++++++ kernel/bpf/queue_stack_maps.c | 288 +++++++++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 30 +++- kernel/bpf/verifier.c | 28 +++- net/core/filter.c | 6 + 10 files changed, 426 insertions(+), 18 deletions(-) create mode 100644 kernel/bpf/queue_stack_maps.c