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selftests/bpf: add selftests for bpf_arena_reserve_pages

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Add selftests for the new bpf_arena_reserve_pages kfunc.

Acked-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250709191312.29840-3-emil@etsalapatis.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Emil Tsalapatis 2025-07-09 15:13:12 -04:00 committed by Alexei Starovoitov
parent 8fc3d2d8b5
commit 9f9559f0ac
3 changed files with 207 additions and 0 deletions
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3
tools/testing/selftests/bpf/bpf_arena_common.h
View File

@ -46,8 +46,11 @@
void __arena* bpf_arena_alloc_pages(void *map, void __arena *addr, __u32 page_cnt,
int node_id, __u64 flags) __ksym __weak;
int bpf_arena_reserve_pages(void *map, void __arena *addr, __u32 page_cnt) __ksym __weak;
void bpf_arena_free_pages(void *map, void __arena *ptr, __u32 page_cnt) __ksym __weak;
#define arena_base(map) ((void __arena *)((struct bpf_arena *)(map))->user_vm_start)
#else /* when compiled as user space code */
#define __arena

106
tools/testing/selftests/bpf/progs/verifier_arena.c
View File

@ -3,6 +3,7 @@
#define BPF_NO_KFUNC_PROTOTYPES
#include <vmlinux.h>
#include <errno.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
#include "bpf_misc.h"
@ -114,6 +115,111 @@ int basic_alloc3(void *ctx)
return 0;
}
SEC("syscall")
__success __retval(0)
int basic_reserve1(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
char __arena *page;
int ret;
page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (!page)
return 1;
page += __PAGE_SIZE;
/* Reserve the second page */
ret = bpf_arena_reserve_pages(&arena, page, 1);
if (ret)
return 2;
/* Try to explicitly allocate the reserved page. */
page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
if (page)
return 3;
/* Try to implicitly allocate the page (since there's only 2 of them). */
page = bpf_arena_alloc_pages(&arena, NULL, 1, NUMA_NO_NODE, 0);
if (page)
return 4;
#endif
return 0;
}
SEC("syscall")
__success __retval(0)
int basic_reserve2(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
char __arena *page;
int ret;
page = arena_base(&arena);
ret = bpf_arena_reserve_pages(&arena, page, 1);
if (ret)
return 1;
page = bpf_arena_alloc_pages(&arena, page, 1, NUMA_NO_NODE, 0);
if ((u64)page)
return 2;
#endif
return 0;
}
/* Reserve the same page twice, should return -EBUSY. */
SEC("syscall")
__success __retval(0)
int reserve_twice(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
char __arena *page;
int ret;
page = arena_base(&arena);
ret = bpf_arena_reserve_pages(&arena, page, 1);
if (ret)
return 1;
ret = bpf_arena_reserve_pages(&arena, page, 1);
if (ret != -EBUSY)
return 2;
#endif
return 0;
}
/* Try to reserve past the end of the arena. */
SEC("syscall")
__success __retval(0)
int reserve_invalid_region(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
char __arena *page;
int ret;
/* Try a NULL pointer. */
ret = bpf_arena_reserve_pages(&arena, NULL, 3);
if (ret != -EINVAL)
return 1;
page = arena_base(&arena);
ret = bpf_arena_reserve_pages(&arena, page, 3);
if (ret != -EINVAL)
return 2;
ret = bpf_arena_reserve_pages(&arena, page, 4096);
if (ret != -EINVAL)
return 3;
ret = bpf_arena_reserve_pages(&arena, page, (1ULL << 32) - 1);
if (ret != -EINVAL)
return 4;
#endif
return 0;
}
SEC("iter.s/bpf_map")
__success __log_level(2)
int iter_maps1(struct bpf_iter__bpf_map *ctx)

98
tools/testing/selftests/bpf/progs/verifier_arena_large.c
View File

@ -67,6 +67,104 @@ int big_alloc1(void *ctx)
return 0;
}
/* Try to access a reserved page. Behavior should be identical with accessing unallocated pages. */
SEC("syscall")
__success __retval(0)
int access_reserved(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
volatile char __arena *page;
char __arena *base;
const size_t len = 4;
int ret, i;
/* Get a separate region of the arena. */
page = base = arena_base(&arena) + 16384 * PAGE_SIZE;
ret = bpf_arena_reserve_pages(&arena, base, len);
if (ret)
return 1;
/* Try to dirty reserved memory. */
for (i = 0; i < len && can_loop; i++)
*page = 0x5a;
for (i = 0; i < len && can_loop; i++) {
page = (volatile char __arena *)(base + i * PAGE_SIZE);
/*
* Error out in case either the write went through,
* or the address has random garbage.
*/
if (*page == 0x5a)
return 2 + 2 * i;
if (*page)
return 2 + 2 * i + 1;
}
#endif
return 0;
}
/* Try to allocate a region overlapping with a reservation. */
SEC("syscall")
__success __retval(0)
int request_partially_reserved(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
volatile char __arena *page;
char __arena *base;
int ret;
/* Add an arbitrary page offset. */
page = base = arena_base(&arena) + 4096 * __PAGE_SIZE;
ret = bpf_arena_reserve_pages(&arena, base + 3 * __PAGE_SIZE, 4);
if (ret)
return 1;
page = bpf_arena_alloc_pages(&arena, base, 5, NUMA_NO_NODE, 0);
if ((u64)page != 0ULL)
return 2;
#endif
return 0;
}
SEC("syscall")
__success __retval(0)
int free_reserved(void *ctx)
{
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
char __arena *addr;
char __arena *page;
int ret;
/* Add an arbitrary page offset. */
addr = arena_base(&arena) + 32768 * __PAGE_SIZE;
page = bpf_arena_alloc_pages(&arena, addr, 2, NUMA_NO_NODE, 0);
if (!page)
return 1;
ret = bpf_arena_reserve_pages(&arena, addr + 2 * __PAGE_SIZE, 2);
if (ret)
return 2;
/*
* Reserved and allocated pages should be interchangeable for
* bpf_arena_free_pages(). Free a reserved and an allocated
* page with a single call.
*/
bpf_arena_free_pages(&arena, addr + __PAGE_SIZE , 2);
/* The free call above should have succeeded, so this allocation should too. */
page = bpf_arena_alloc_pages(&arena, addr + __PAGE_SIZE, 2, NUMA_NO_NODE, 0);
if (!page)
return 3;
#endif
return 0;
}
#if defined(__BPF_FEATURE_ADDR_SPACE_CAST)
#define PAGE_CNT 100
__u8 __arena * __arena page[PAGE_CNT]; /* occupies the first page */