[PATCH v8 2/5] ebpf: Added eBPF initialization by fds.

[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>
---
 ebpf/ebpf_rss-stub.c |  9 +++++++--
 ebpf/ebpf_rss.c      | 27 +++++++++++++++++++++++++++
 ebpf/ebpf_rss.h      |  5 +++++
 3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/ebpf/ebpf_rss-stub.c b/ebpf/ebpf_rss-stub.c
index e71e229190..1c158b6e06 100644
--- a/ebpf/ebpf_rss-stub.c
+++ b/ebpf/ebpf_rss-stub.c
@@ -6,8 +6,7 @@
  * Authors:
  *  Yuri Benditovich <yuri.benditovich@daynix.com>
  *
- * This work is licensed under the terms of the GNU GPL, version 2.  See
- * the COPYING file in the top-level directory.
+ * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include "qemu/osdep.h"
@@ -28,6 +27,12 @@ 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 c6e10265a7..20c44f2baa 100644
--- a/ebpf/ebpf_rss.c
+++ b/ebpf/ebpf_rss.c
@@ -145,6 +145,33 @@ 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 404cf53613..39646aff6f 100644
--- a/ebpf/ebpf_rss.h
+++ b/ebpf/ebpf_rss.h
@@ -13,6 +13,8 @@
 #ifndef QEMU_EBPF_RSS_H
 #define QEMU_EBPF_RSS_H
 
+#define EBPF_RSS_MAX_FDS 4
+
 struct EBPFRSSContext {
     void *obj;
     int program_fd;
@@ -40,6 +42,9 @@ 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);
 
-- 
2.43.0