ebpf: Added traces back. Changed source set for eBPF to 'system'.

There was an issue with Qemu build with "--disable-system".
The traces could be generated and the build fails.
The traces were 'cut out' for previous patches, and overall,
the 'system' source set should be used like in pre-'eBPF blob' patches.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

ebpf/ebpf_rss.c

@@ -25,6 +25,8 @@
 #include "ebpf/rss.bpf.skeleton.h"
 #include "ebpf/ebpf.h"
 
+#include "trace.h"
+
 void ebpf_rss_init(struct EBPFRSSContext *ctx)
 {
     if (ctx != NULL) {
@@ -55,18 +57,21 @@ 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;
     }
 
@@ -108,12 +113,14 @@ 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;
     }
 

ebpf/trace.h

@@ -0,0 +1 @@
+#include "trace/trace-ebpf.h"