Commit 9f9559f0 authored by Emil Tsalapatis's avatar Emil Tsalapatis Committed by Alexei Starovoitov
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selftests/bpf: add selftests for bpf_arena_reserve_pages 



Add selftests for the new bpf_arena_reserve_pages kfunc.

Acked-by: default avatarYonghong Song <yonghong.song@linux.dev>
Signed-off-by: default avatarEmil Tsalapatis <emil@etsalapatis.com>
Acked-by: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20250709191312.29840-3-emil@etsalapatis.com


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 8fc3d2d8

tools/testing/selftests/bpf/bpf_arena_common.h

+3 −0
Original line number Diff line number Diff line
@@ -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

tools/testing/selftests/bpf/progs/verifier_arena.c

+106 −0
Original line number Diff line number Diff line
@@ -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)

tools/testing/selftests/bpf/progs/verifier_arena_large.c

+98 −0
Original line number Diff line number Diff line
@@ -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 */