From 333b3e5fab751cce9f077b827563296c797ff399 Mon Sep 17 00:00:00 2001 From: Andrew Melnychenko Date: Mon, 5 Feb 2024 18:54:31 +0200 Subject: [PATCH] ebpf: Added eBPF map update through mmap. 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 Signed-off-by: Jason Wang --- ebpf/ebpf_rss.c | 117 ++++++++++++++++++++++++++++++++++++++---------- ebpf/ebpf_rss.h | 5 +++ 2 files changed, 99 insertions(+), 23 deletions(-) diff --git a/ebpf/ebpf_rss.c b/ebpf/ebpf_rss.c index cee658c158..f774d9636b 100644 --- a/ebpf/ebpf_rss.c +++ b/ebpf/ebpf_rss.c @@ -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; } diff --git a/ebpf/ebpf_rss.h b/ebpf/ebpf_rss.h index bf3f2572c7..ab08a7266d 100644 --- a/ebpf/ebpf_rss.h +++ b/ebpf/ebpf_rss.h @@ -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 {