[PULL 5/8] ebpf: Added eBPF initialization by fds.

[Jason Wang <jasowang@redhat.com>]

From: Andrew Melnychenko <andrew@daynix.com>

It allows using file descriptors of eBPF provided
outside of QEMU.
QEMU may be run without capabilities for eBPF and run
RSS program provided by management tool(g.e. libvirt).

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 ebpf/ebpf_rss-stub.c |  6 ++++++
 ebpf/ebpf_rss.c      | 27 +++++++++++++++++++++++++++
 ebpf/ebpf_rss.h      |  5 +++++
 3 files changed, 38 insertions(+)

diff --git a/ebpf/ebpf_rss-stub.c b/ebpf/ebpf_rss-stub.c
index e71e229190..8d7fae2ad9 100644
--- a/ebpf/ebpf_rss-stub.c
+++ b/ebpf/ebpf_rss-stub.c
@@ -28,6 +28,12 @@ bool ebpf_rss_load(struct EBPFRSSContext *ctx)
     return false;
 }
 
+bool ebpf_rss_load_fds(struct EBPFRSSContext *ctx, int program_fd,
+                       int config_fd, int toeplitz_fd, int table_fd)
+{
+    return false;
+}
+
 bool ebpf_rss_set_all(struct EBPFRSSContext *ctx, struct EBPFRSSConfig *config,
                       uint16_t *indirections_table, uint8_t *toeplitz_key)
 {
diff --git a/ebpf/ebpf_rss.c b/ebpf/ebpf_rss.c
index f774d9636b..150aa40813 100644
--- a/ebpf/ebpf_rss.c
+++ b/ebpf/ebpf_rss.c
@@ -146,6 +146,33 @@ error:
     return false;
 }
 
+bool ebpf_rss_load_fds(struct EBPFRSSContext *ctx, int program_fd,
+                       int config_fd, int toeplitz_fd, int table_fd)
+{
+    if (ebpf_rss_is_loaded(ctx)) {
+        return false;
+    }
+
+    if (program_fd < 0 || config_fd < 0 || toeplitz_fd < 0 || table_fd < 0) {
+        return false;
+    }
+
+    ctx->program_fd = program_fd;
+    ctx->map_configuration = config_fd;
+    ctx->map_toeplitz_key = toeplitz_fd;
+    ctx->map_indirections_table = table_fd;
+
+    if (!ebpf_rss_mmap(ctx)) {
+        ctx->program_fd = -1;
+        ctx->map_configuration = -1;
+        ctx->map_toeplitz_key = -1;
+        ctx->map_indirections_table = -1;
+        return false;
+    }
+
+    return true;
+}
+
 static bool ebpf_rss_set_config(struct EBPFRSSContext *ctx,
                                 struct EBPFRSSConfig *config)
 {
diff --git a/ebpf/ebpf_rss.h b/ebpf/ebpf_rss.h
index ab08a7266d..239242b0d2 100644
--- a/ebpf/ebpf_rss.h
+++ b/ebpf/ebpf_rss.h
@@ -14,6 +14,8 @@
 #ifndef QEMU_EBPF_RSS_H
 #define QEMU_EBPF_RSS_H
 
+#define EBPF_RSS_MAX_FDS 4
+
 struct EBPFRSSContext {
     void *obj;
     int program_fd;
@@ -41,6 +43,9 @@ bool ebpf_rss_is_loaded(struct EBPFRSSContext *ctx);
 
 bool ebpf_rss_load(struct EBPFRSSContext *ctx);
 
+bool ebpf_rss_load_fds(struct EBPFRSSContext *ctx, int program_fd,
+                       int config_fd, int toeplitz_fd, int table_fd);
+
 bool ebpf_rss_set_all(struct EBPFRSSContext *ctx, struct EBPFRSSConfig *config,
                       uint16_t *indirections_table, uint8_t *toeplitz_key);
 
-- 
2.42.0