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authorAndrew Melnychenko <andrew@daynix.com>2024-03-12 18:57:57 +0800
committerJason Wang <jasowang@redhat.com>2024-03-12 19:31:47 +0800
commite88899fa90635da7f5c1e245028288755bb5fbd4 (patch)
treea7e9660841f442b403f407088fd2726ea0c5f315 /ebpf
parent6b230b7dfcd8123a902e41cd313714b5a57dcac4 (diff)
qmp: Added new command to retrieve eBPF blob.
Now, the binary objects may be retrieved by id. It would require for future qmp commands that may require specific eBPF blob. Added command "request-ebpf". This command returns eBPF program encoded base64. The program taken from the skeleton and essentially is an ELF object that can be loaded in the future with libbpf. The reason to use the command to provide the eBPF object instead of a separate artifact was to avoid issues related to finding the eBPF itself. eBPF object is an ELF binary that contains the eBPF program and eBPF map description(BTF). Overall, eBPF object should contain the program and enough metadata to create/load eBPF with libbpf. As the eBPF maps/program should correspond to QEMU, the eBPF can't be used from different QEMU build. The first solution was a helper that comes with QEMU and loads appropriate eBPF objects. And the issue is to find a proper helper if the system has several different QEMUs installed and/or built from the source, which helpers may not be compatible. Another issue is QEMU updating while there is a running QEMU instance. With an updated helper, it may not be possible to hotplug virtio-net device to the already running QEMU. Overall, requesting the eBPF object from QEMU itself solves possible failures with acceptable effort. Links: [PATCH 3/5] qmp: Added the helper stamp check. https://lore.kernel.org/all/20230219162100.174318-4-andrew@daynix.com/ Signed-off-by: Andrew Melnychenko <andrew@daynix.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'ebpf')
-rw-r--r--ebpf/ebpf.c69
-rw-r--r--ebpf/ebpf.h29
-rw-r--r--ebpf/ebpf_rss.c11
-rw-r--r--ebpf/meson.build2
-rw-r--r--ebpf/trace.h1
5 files changed, 104 insertions, 8 deletions
diff --git a/ebpf/ebpf.c b/ebpf/ebpf.c
new file mode 100644
index 0000000000..2d73beb479
--- /dev/null
+++ b/ebpf/ebpf.c
@@ -0,0 +1,69 @@
+/*
+ * QEMU eBPF binary declaration routine.
+ *
+ * Developed by Daynix Computing LTD (http://www.daynix.com)
+ *
+ * Authors:
+ * Andrew Melnychenko <andrew@daynix.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/queue.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-ebpf.h"
+#include "ebpf/ebpf.h"
+
+typedef struct ElfBinaryDataEntry {
+ int id;
+ const void *data;
+ size_t datalen;
+
+ QSLIST_ENTRY(ElfBinaryDataEntry) node;
+} ElfBinaryDataEntry;
+
+static QSLIST_HEAD(, ElfBinaryDataEntry) ebpf_elf_obj_list =
+ QSLIST_HEAD_INITIALIZER();
+
+void ebpf_register_binary_data(int id, const void *data, size_t datalen)
+{
+ struct ElfBinaryDataEntry *dataentry = NULL;
+
+ dataentry = g_new0(struct ElfBinaryDataEntry, 1);
+ dataentry->data = data;
+ dataentry->datalen = datalen;
+ dataentry->id = id;
+
+ QSLIST_INSERT_HEAD(&ebpf_elf_obj_list, dataentry, node);
+}
+
+const void *ebpf_find_binary_by_id(int id, size_t *sz, Error **errp)
+{
+ struct ElfBinaryDataEntry *it = NULL;
+ QSLIST_FOREACH(it, &ebpf_elf_obj_list, node) {
+ if (id == it->id) {
+ *sz = it->datalen;
+ return it->data;
+ }
+ }
+
+ error_setg(errp, "can't find eBPF object with id: %d", id);
+
+ return NULL;
+}
+
+EbpfObject *qmp_request_ebpf(EbpfProgramID id, Error **errp)
+{
+ EbpfObject *ret = NULL;
+ size_t size = 0;
+ const void *data = ebpf_find_binary_by_id(id, &size, errp);
+ if (!data) {
+ return NULL;
+ }
+
+ ret = g_new0(EbpfObject, 1);
+ ret->object = g_base64_encode(data, size);
+
+ return ret;
+}
diff --git a/ebpf/ebpf.h b/ebpf/ebpf.h
new file mode 100644
index 0000000000..378d4e9c70
--- /dev/null
+++ b/ebpf/ebpf.h
@@ -0,0 +1,29 @@
+/*
+ * QEMU eBPF binary declaration routine.
+ *
+ * Developed by Daynix Computing LTD (http://www.daynix.com)
+ *
+ * Authors:
+ * Andrew Melnychenko <andrew@daynix.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef EBPF_H
+#define EBPF_H
+
+
+void ebpf_register_binary_data(int id, const void *data,
+ size_t datalen);
+const void *ebpf_find_binary_by_id(int id, size_t *sz,
+ struct Error **errp);
+
+#define ebpf_binary_init(id, fn) \
+static void __attribute__((constructor)) ebpf_binary_init_ ## fn(void) \
+{ \
+ size_t datalen = 0; \
+ const void *data = fn(&datalen); \
+ ebpf_register_binary_data(id, data, datalen); \
+}
+
+#endif /* EBPF_H */
diff --git a/ebpf/ebpf_rss.c b/ebpf/ebpf_rss.c
index 150aa40813..2e506f9743 100644
--- a/ebpf/ebpf_rss.c
+++ b/ebpf/ebpf_rss.c
@@ -13,6 +13,8 @@
#include "qemu/osdep.h"
#include "qemu/error-report.h"
+#include "qapi/qapi-types-misc.h"
+#include "qapi/qapi-commands-ebpf.h"
#include <bpf/libbpf.h>
#include <bpf/bpf.h>
@@ -21,7 +23,7 @@
#include "ebpf/ebpf_rss.h"
#include "ebpf/rss.bpf.skeleton.h"
-#include "trace.h"
+#include "ebpf/ebpf.h"
void ebpf_rss_init(struct EBPFRSSContext *ctx)
{
@@ -53,21 +55,18 @@ static bool ebpf_rss_mmap(struct EBPFRSSContext *ctx)
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;
}
@@ -109,14 +108,12 @@ bool ebpf_rss_load(struct EBPFRSSContext *ctx)
rss_bpf_ctx = rss_bpf__open();
if (rss_bpf_ctx == NULL) {
- trace_ebpf_error("eBPF RSS", "can not open eBPF RSS object");
goto error;
}
bpf_program__set_type(rss_bpf_ctx->progs.tun_rss_steering_prog, BPF_PROG_TYPE_SOCKET_FILTER);
if (rss_bpf__load(rss_bpf_ctx)) {
- trace_ebpf_error("eBPF RSS", "can not load RSS program");
goto error;
}
@@ -261,3 +258,5 @@ void ebpf_rss_unload(struct EBPFRSSContext *ctx)
ctx->map_toeplitz_key = -1;
ctx->map_indirections_table = -1;
}
+
+ebpf_binary_init(EBPF_PROGRAMID_RSS, rss_bpf__elf_bytes)
diff --git a/ebpf/meson.build b/ebpf/meson.build
index 2f627d6c7d..c5bf9295a2 100644
--- a/ebpf/meson.build
+++ b/ebpf/meson.build
@@ -1 +1 @@
-system_ss.add(when: libbpf, if_true: files('ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))
+common_ss.add(when: libbpf, if_true: files('ebpf.c', 'ebpf_rss.c'), if_false: files('ebpf_rss-stub.c'))
diff --git a/ebpf/trace.h b/ebpf/trace.h
deleted file mode 100644
index abefc46ab1..0000000000
--- a/ebpf/trace.h
+++ /dev/null
@@ -1 +0,0 @@
-#include "trace/trace-ebpf.h"