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ebpf: Added eBPF map update through mmap.

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Changed eBPF map updates through mmaped array.
Mmaped arrays provide direct access to map data.
It should omit using bpf_map_update_elem() call,
which may require capabilities that are not present.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
This commit is contained in:
Andrew Melnychenko 2024-02-05 18:54:31 +02:00 committed by Jason Wang
parent 6a5287ce80
commit 333b3e5fab
2 changed files with 99 additions and 23 deletions
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117
ebpf/ebpf_rss.c
View File

@ -27,19 +27,83 @@ void ebpf_rss_init(struct EBPFRSSContext *ctx)
{
if (ctx != NULL) {
ctx->obj = NULL;
ctx->program_fd = -1;
ctx->map_configuration = -1;
ctx->map_toeplitz_key = -1;
ctx->map_indirections_table = -1;
ctx->mmap_configuration = NULL;
ctx->mmap_toeplitz_key = NULL;
ctx->mmap_indirections_table = NULL;
}
}
bool ebpf_rss_is_loaded(struct EBPFRSSContext *ctx)
{
return ctx != NULL && ctx->obj != NULL;
return ctx != NULL && (ctx->obj != NULL || ctx->program_fd != -1);
}
static bool ebpf_rss_mmap(struct EBPFRSSContext *ctx)
{
if (!ebpf_rss_is_loaded(ctx)) {
return false;
}
ctx->mmap_configuration = mmap(NULL, qemu_real_host_page_size(),
PROT_READ | PROT_WRITE, MAP_SHARED,
ctx->map_configuration, 0);
if (ctx->mmap_configuration == MAP_FAILED) {
trace_ebpf_error("eBPF RSS", "can not mmap eBPF configuration array");
return false;
}
ctx->mmap_toeplitz_key = mmap(NULL, qemu_real_host_page_size(),
PROT_READ | PROT_WRITE, MAP_SHARED,
ctx->map_toeplitz_key, 0);
if (ctx->mmap_toeplitz_key == MAP_FAILED) {
trace_ebpf_error("eBPF RSS", "can not mmap eBPF toeplitz key");
goto toeplitz_fail;
}
ctx->mmap_indirections_table = mmap(NULL, qemu_real_host_page_size(),
PROT_READ | PROT_WRITE, MAP_SHARED,
ctx->map_indirections_table, 0);
if (ctx->mmap_indirections_table == MAP_FAILED) {
trace_ebpf_error("eBPF RSS", "can not mmap eBPF indirection table");
goto indirection_fail;
}
return true;
indirection_fail:
munmap(ctx->mmap_toeplitz_key, qemu_real_host_page_size());
ctx->mmap_toeplitz_key = NULL;
toeplitz_fail:
munmap(ctx->mmap_configuration, qemu_real_host_page_size());
ctx->mmap_configuration = NULL;
ctx->mmap_indirections_table = NULL;
return false;
}
static void ebpf_rss_munmap(struct EBPFRSSContext *ctx)
{
if (!ebpf_rss_is_loaded(ctx)) {
return;
}
munmap(ctx->mmap_indirections_table, qemu_real_host_page_size());
munmap(ctx->mmap_toeplitz_key, qemu_real_host_page_size());
munmap(ctx->mmap_configuration, qemu_real_host_page_size());
ctx->mmap_configuration = NULL;
ctx->mmap_toeplitz_key = NULL;
ctx->mmap_indirections_table = NULL;
}
bool ebpf_rss_load(struct EBPFRSSContext *ctx)
{
struct rss_bpf *rss_bpf_ctx;
if (ctx == NULL) {
if (ebpf_rss_is_loaded(ctx)) {
return false;
}
@ -66,10 +130,18 @@ bool ebpf_rss_load(struct EBPFRSSContext *ctx)
ctx->map_toeplitz_key = bpf_map__fd(
rss_bpf_ctx->maps.tap_rss_map_toeplitz_key);
if (!ebpf_rss_mmap(ctx)) {
goto error;
}
return true;
error:
rss_bpf__destroy(rss_bpf_ctx);
ctx->obj = NULL;
ctx->program_fd = -1;
ctx->map_configuration = -1;
ctx->map_toeplitz_key = -1;
ctx->map_indirections_table = -1;
return false;
}
@ -77,15 +149,11 @@ error:
static bool ebpf_rss_set_config(struct EBPFRSSContext *ctx,
struct EBPFRSSConfig *config)
{
uint32_t map_key = 0;
if (!ebpf_rss_is_loaded(ctx)) {
return false;
}
if (bpf_map_update_elem(ctx->map_configuration,
&map_key, config, 0) < 0) {
return false;
}
memcpy(ctx->mmap_configuration, config, sizeof(*config));
return true;
}
@ -93,27 +161,19 @@ static bool ebpf_rss_set_indirections_table(struct EBPFRSSContext *ctx,
uint16_t *indirections_table,
size_t len)
{
uint32_t i = 0;
if (!ebpf_rss_is_loaded(ctx) || indirections_table == NULL ||
len > VIRTIO_NET_RSS_MAX_TABLE_LEN) {
return false;
}
for (; i < len; ++i) {
if (bpf_map_update_elem(ctx->map_indirections_table, &i,
indirections_table + i, 0) < 0) {
return false;
}
}
memcpy(ctx->mmap_indirections_table, indirections_table,
sizeof(*indirections_table) * len);
return true;
}
static bool ebpf_rss_set_toepliz_key(struct EBPFRSSContext *ctx,
uint8_t *toeplitz_key)
{
uint32_t map_key = 0;
/* prepare toeplitz key */
uint8_t toe[VIRTIO_NET_RSS_MAX_KEY_SIZE] = {};
@ -123,10 +183,7 @@ static bool ebpf_rss_set_toepliz_key(struct EBPFRSSContext *ctx,
memcpy(toe, toeplitz_key, VIRTIO_NET_RSS_MAX_KEY_SIZE);
*(uint32_t *)toe = ntohl(*(uint32_t *)toe);
if (bpf_map_update_elem(ctx->map_toeplitz_key, &map_key, toe,
0) < 0) {
return false;
}
memcpy(ctx->mmap_toeplitz_key, toe, VIRTIO_NET_RSS_MAX_KEY_SIZE);
return true;
}
@ -160,6 +217,20 @@ void ebpf_rss_unload(struct EBPFRSSContext *ctx)
return;
}
rss_bpf__destroy(ctx->obj);
ebpf_rss_munmap(ctx);
if (ctx->obj) {
rss_bpf__destroy(ctx->obj);
} else {
close(ctx->program_fd);
close(ctx->map_configuration);
close(ctx->map_toeplitz_key);
close(ctx->map_indirections_table);
}
ctx->obj = NULL;
ctx->program_fd = -1;
ctx->map_configuration = -1;
ctx->map_toeplitz_key = -1;
ctx->map_indirections_table = -1;
}

5
ebpf/ebpf_rss.h
View File

@ -20,6 +20,11 @@ struct EBPFRSSContext {
int map_configuration;
int map_toeplitz_key;
int map_indirections_table;
/* mapped eBPF maps for direct access to omit bpf_map_update_elem() */
void *mmap_configuration;
void *mmap_toeplitz_key;
void *mmap_indirections_table;
};
struct EBPFRSSConfig {