From 691513d264f1e259a09a3a0e4f1f4f737154ad6d Mon Sep 17 00:00:00 2001
From: Luis Gerhorst <gerhorst@cs.fau.de>
Date: Thu, 21 Dec 2023 14:36:03 +0100
Subject: [PATCH] [DRAFT] bpf: Insert marked spec_v1 instructions
---
kernel/bpf/verifier.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 1505eafadf2d..520daa13a307 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -17631,6 +17631,37 @@ static int convert_ctx_accesses(struct bpf_verifier_env *env)
for (i = 0; i < insn_cnt; i++, insn++) {
bpf_convert_ctx_access_t convert_ctx_access;
+ if (env->insn_aux_data[i + delta].nospec_v1) {
+ /* TODO: Check that previous instruction is not already
+ * a nospec. Or even better, insert the lfence only at
+ * the beginning of the basic block. */
+ struct bpf_insn patch[] = {
+ BPF_ST_NOSPEC_V1(),
+ *insn,
+ };
+ cnt = ARRAY_SIZE(patch);
+ new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+ delta += cnt - 1;
+ env->prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ }
+
+ if (env->insn_aux_data[i + delta].nospec_v1_result) {
+ struct bpf_insn patch[] = {
+ *insn,
+ BPF_ST_NOSPEC_V1(),
+ };
+ cnt = ARRAY_SIZE(patch);
+ new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+ if (!new_prog)
+ return -ENOMEM;
+ delta += cnt - 1;
+ env->prog = new_prog;
+ insn = new_prog->insnsi + i + delta;
+ }
+
if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
--
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