On 11/12/2020 4:35 PM, Ciara Loftus wrote:
'uint64_t' is used to hold pointers in multiple locations in the
copy-mode code (used for kernels before 5.4). For a 32-bit build
this assumption is wrong and results in build errors. This commit
replaces such instances of 'uint64_t' with 'uintptr_t'.
While the copy-mode code will now compile for 32-bit, the PMD is
not expected to work and will fail at initialisation due to some
limitations in the kernel that were subsequently removed in v5.4.
Add a note to the docs to flag this limitation.
Fixes: f1debd77efaf ("net/af_xdp: introduce AF_XDP PMD")
Fixes: d8a210774e1d ("net/af_xdp: support unaligned umem chunks")
Cc: sta...@dpdk.org
Signed-off-by: Ciara Loftus <ciara.lof...@intel.com>
---
doc/guides/nics/af_xdp.rst | 1 +
drivers/net/af_xdp/rte_eth_af_xdp.c | 6 +++---
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
index 052e59a3ae..5ed24374f8 100644
--- a/doc/guides/nics/af_xdp.rst
+++ b/doc/guides/nics/af_xdp.rst
@@ -50,6 +50,7 @@ This is a Linux-specific PMD, thus the following
prerequisites apply:
* For PMD zero copy, it requires kernel version later than v5.4-rc1;
* For shared_umem, it requires kernel version v5.10 or later and libbpf
version
v0.2.0 or later.
+* For 32-bit OS, a kernel with version 5.4 or later is required.
+1 to doc update
Set up an af_xdp interface
-----------------------------
diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c
b/drivers/net/af_xdp/rte_eth_af_xdp.c
index 4076ff797c..75ff1c00b2 100644
--- a/drivers/net/af_xdp/rte_eth_af_xdp.c
+++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
@@ -349,7 +349,7 @@ af_xdp_rx_cp(void *queue, struct rte_mbuf **bufs, uint16_t
nb_pkts)
for (i = 0; i < rcvd; i++) {
const struct xdp_desc *desc;
- uint64_t addr;
+ uintptr_t addr;
uint32_t len;
void *pkt;
@@ -402,7 +402,7 @@ pull_umem_cq(struct xsk_umem_info *umem, int size, struct xsk_ring_cons *cq)
n = xsk_ring_cons__peek(cq, size, &idx_cq);
for (i = 0; i < n; i++) {
- uint64_t addr;
+ uintptr_t addr;
addr = *xsk_ring_cons__comp_addr(cq, idx_cq++);
Hi Ciara,
As far as I can see the API 'xsk_ring_cons__comp_addr()' returns fixed size
variable ('__u64'),
and when the PMD is compiled for 32bit, won't it be assigning a 64bit variable
to the 32bit storage.
I guess libbpf also needs to be adjusted for the 32bit support, what about
making PMD changes after libbpf changed?
#if defined(XDP_UMEM_UNALIGNED_CHUNK_FLAG)
addr = xsk_umem__extract_addr(addr);
@@ -1005,7 +1005,7 @@ xsk_umem_info *xdp_umem_configure(struct pmd_internals
*internals,
char ring_name[RTE_RING_NAMESIZE];
char mz_name[RTE_MEMZONE_NAMESIZE];
int ret;
- uint64_t i;
+ uintptr_t i;
Not sure on this one, 'i' seems not to hold a pointer but index, and result of
calculation cast to "void *", I assume intention is to prevent calculation
result to be 64 bit to cover the case "void *" is 4 bytes, for that what do you
think making variable uint32_t?
