Hi Stephen,
As part of hash calculation logic, the hash value is going beyond 32-bits and
thus the eBPF verifier throws error with the 32-bit hash variable.
So, I need to modify as 64-bit hash variable to resolve the BPF verifier error.
Here, in the code this rte_softrss_be() function is returning the hash
variable, which is a 64-bit value, so modified the return type from 32-bit to
64-bit.
==================
-static __u32 __attribute__((always_inline))
-rte_softrss_be(const __u32 *input_tuple, const uint8_t *rss_key,
- __u8 input_len)
+static __u64 __attribute__((always_inline))
+rte_softrss_be(const __u32 *input_tuple, __u8 input_len)
{
- __u32 i, j, hash = 0;
-#pragma unroll
+ __u32 i, j;
+ __u64 hash = 0;
+#pragma clang loop unroll(full)
for (j = 0; j < input_len; j++) {
-#pragma unroll
+#pragma clang loop unroll(full)
for (i = 0; i < 32; i++) {
if (input_tuple[j] & (1U << (31 - i))) {
hash ^= ((const __u32 *)def_rss_key)[j] << i |
- (__u32)((uint64_t)
+ (__u32)((__u64)
(((const __u32 *)def_rss_key)[j + 1])
>> (32 - i));
}
@@ -119,137 +107,78 @@ rte_softrss_be(const __u32 *input_tuple, const uint8_t
*rss_key,
return hash;
}
======================
Thanks,
Madhuker.
-----Original Message-----
From: Stephen Hemminger <step...@networkplumber.org>
Sent: 05 January 2024 02:09
To: Madhuker Mythri <madhuker.myt...@oracle.com>
Cc: ferruh.yi...@amd.com; dev@dpdk.org
Subject: [External] : Re: [PATCH] net/tap: Modified TAP BPF program as per the
new Kernel-version upgrade requirements.
On Thu, 4 Jan 2024 22:57:56 +0530
madhuker.myt...@oracle.com wrote:
> -static __u32 __attribute__((always_inline)) -rte_softrss_be(const
> __u32 *input_tuple, const uint8_t *rss_key,
> - __u8 input_len)
> +static __u64 __attribute__((always_inline)) rte_softrss_be(const
> +__u32 *input_tuple, __u8 input_len)
Why the change to u64?
This is not part of the bug fix and not how RSS is defined.
