[RFC PATCH 1/5] ebpf: Added eBPF initialization by fds.

[Andrew Melnychenko]

eBPF RSS context may be initialized by program fd and map fds.
virtio-net may provide fds passed by libvirt.

Signed-off-by: Andrew Melnychenko <andrew@daynix.com>
---
 ebpf/ebpf_rss-stub.c |  6 ++++++
 ebpf/ebpf_rss.c      | 31 ++++++++++++++++++++++++++++---
 ebpf/ebpf_rss.h      |  5 +++++
 3 files changed, 39 insertions(+), 3 deletions(-)

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 118c68da83..6e9b88efed 100644
--- a/ebpf/ebpf_rss.c
+++ b/ebpf/ebpf_rss.c
@@ -27,19 +27,20 @@ void ebpf_rss_init(struct EBPFRSSContext *ctx)
 {
     if (ctx != NULL) {
         ctx->obj = NULL;
+        ctx->program_fd = -1;
     }
 }
 
 bool ebpf_rss_is_loaded(struct EBPFRSSContext *ctx)
 {
-    return ctx != NULL && ctx->obj != NULL;
+    return ctx != NULL && (ctx->obj != NULL || ctx->program_fd != -1);
 }
 
 bool ebpf_rss_load(struct EBPFRSSContext *ctx)
 {
     struct rss_bpf *rss_bpf_ctx;
 
-    if (ctx == NULL) {
+    if (ctx == NULL || ebpf_rss_is_loaded(ctx)) {
         return false;
     }
 
@@ -70,10 +71,26 @@ bool ebpf_rss_load(struct EBPFRSSContext *ctx)
 error:
     rss_bpf__destroy(rss_bpf_ctx);
     ctx->obj = NULL;
+    ctx->program_fd = -1;
 
     return false;
 }
 
+bool ebpf_rss_load_fds(struct EBPFRSSContext *ctx, int program_fd,
+                       int config_fd, int toeplitz_fd, int table_fd)
+{
+    if (ctx == NULL || ebpf_rss_is_loaded(ctx)) {
+        return false;
+    }
+
+    ctx->program_fd = program_fd;
+    ctx->map_configuration = config_fd;
+    ctx->map_toeplitz_key = toeplitz_fd;
+    ctx->map_indirections_table = table_fd;
+
+    return true;
+}
+
 static bool ebpf_rss_set_config(struct EBPFRSSContext *ctx,
                                 struct EBPFRSSConfig *config)
 {
@@ -160,6 +177,14 @@ void ebpf_rss_unload(struct EBPFRSSContext *ctx)
         return;
     }
 
-    rss_bpf__destroy(ctx->obj);
+    if (ctx->obj != NULL) {
+        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;
 }
diff --git a/ebpf/ebpf_rss.h b/ebpf/ebpf_rss.h
index bf3f2572c7..363859c8bb 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;
@@ -36,6 +38,9 @@ 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);
 
-- 
2.31.1