diff mbox series

[net,v2] nfp: bpf: relax prog rejection for mtu check through max_pkt_offset

Message ID 20211028100036.8477-1-simon.horman@corigine.com (mailing list archive)
State Accepted
Commit 90a881fc352a953f1c8beb61977a2db0818157d4
Delegated to: Netdev Maintainers
Headers show
Series [net,v2] nfp: bpf: relax prog rejection for mtu check through max_pkt_offset | expand

Checks

Context Check Description
netdev/cover_letter success Single patches do not need cover letters
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags
netdev/patch_count success Link
netdev/tree_selection success Clearly marked for net
netdev/subject_prefix success Link
netdev/cc_maintainers warning 10 maintainers not CCed: john.fastabend@gmail.com hawk@kernel.org daniel@iogearbox.net yhs@fb.com songliubraving@fb.com bpf@vger.kernel.org kafai@fb.com kpsingh@kernel.org ast@kernel.org andrii@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success No Fixes tag
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 66 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success No static functions without inline keyword in header files

Commit Message

Simon Horman Oct. 28, 2021, 10 a.m. UTC
From: Yu Xiao <yu.xiao@corigine.com>

MTU change is refused whenever the value of new MTU is bigger than
the max packet bytes that fits in NFP Cluster Target Memory (CTM).
However, an eBPF program doesn't always need to access the whole
packet data.

The maximum direct packet access (DPA) offset has always been
caculated by verifier and stored in the max_pkt_offset field of prog
aux data.

Signed-off-by: Yu Xiao <yu.xiao@corigine.com>
Reviewed-by: Yinjun Zhang <yinjun.zhang@corigine.com>
Reviewed-by: Niklas Soderlund <niklas.soderlund@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c   | 16 +++++++++++-----
 drivers/net/ethernet/netronome/nfp/bpf/main.h   |  2 ++
 .../net/ethernet/netronome/nfp/bpf/offload.c    | 17 +++++++++++++----
 3 files changed, 26 insertions(+), 9 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org Oct. 28, 2021, 12:10 p.m. UTC | #1
Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Thu, 28 Oct 2021 12:00:36 +0200 you wrote:
> From: Yu Xiao <yu.xiao@corigine.com>
> 
> MTU change is refused whenever the value of new MTU is bigger than
> the max packet bytes that fits in NFP Cluster Target Memory (CTM).
> However, an eBPF program doesn't always need to access the whole
> packet data.
> 
> [...]

Here is the summary with links:
  - [net,v2] nfp: bpf: relax prog rejection for mtu check through max_pkt_offset
    https://git.kernel.org/netdev/net/c/90a881fc352a

You are awesome, thank you!
Jakub Kicinski Oct. 28, 2021, 2:58 p.m. UTC | #2
On Thu, 28 Oct 2021 12:00:36 +0200 Simon Horman wrote:
> From: Yu Xiao <yu.xiao@corigine.com>
> 
> MTU change is refused whenever the value of new MTU is bigger than
> the max packet bytes that fits in NFP Cluster Target Memory (CTM).
> However, an eBPF program doesn't always need to access the whole
> packet data.
> 
> The maximum direct packet access (DPA) offset has always been
> caculated by verifier and stored in the max_pkt_offset field of prog
> aux data.
> 
> Signed-off-by: Yu Xiao <yu.xiao@corigine.com>
> Reviewed-by: Yinjun Zhang <yinjun.zhang@corigine.com>
> Reviewed-by: Niklas Soderlund <niklas.soderlund@corigine.com>
> Signed-off-by: Simon Horman <simon.horman@corigine.com>

Looks fine, not sure why it's tagged for net but okay..
diff mbox series

Patch

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index 11c83a99b014..f469950c7265 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.c
@@ -182,15 +182,21 @@  static int
 nfp_bpf_check_mtu(struct nfp_app *app, struct net_device *netdev, int new_mtu)
 {
 	struct nfp_net *nn = netdev_priv(netdev);
-	unsigned int max_mtu;
+	struct nfp_bpf_vnic *bv;
+	struct bpf_prog *prog;
 
 	if (~nn->dp.ctrl & NFP_NET_CFG_CTRL_BPF)
 		return 0;
 
-	max_mtu = nn_readb(nn, NFP_NET_CFG_BPF_INL_MTU) * 64 - 32;
-	if (new_mtu > max_mtu) {
-		nn_info(nn, "BPF offload active, MTU over %u not supported\n",
-			max_mtu);
+	if (nn->xdp_hw.prog) {
+		prog = nn->xdp_hw.prog;
+	} else {
+		bv = nn->app_priv;
+		prog = bv->tc_prog;
+	}
+
+	if (nfp_bpf_offload_check_mtu(nn, prog, new_mtu)) {
+		nn_info(nn, "BPF offload active, potential packet access beyond hardware packet boundary");
 		return -EBUSY;
 	}
 	return 0;
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index d0e17eebddd9..16841bb750b7 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.h
@@ -560,6 +560,8 @@  bool nfp_is_subprog_start(struct nfp_insn_meta *meta);
 void nfp_bpf_jit_prepare(struct nfp_prog *nfp_prog);
 int nfp_bpf_jit(struct nfp_prog *prog);
 bool nfp_bpf_supported_opcode(u8 code);
+bool nfp_bpf_offload_check_mtu(struct nfp_net *nn, struct bpf_prog *prog,
+			       unsigned int mtu);
 
 int nfp_verify_insn(struct bpf_verifier_env *env, int insn_idx,
 		    int prev_insn_idx);
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/offload.c b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
index 53851853562c..9d97cd281f18 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
@@ -481,19 +481,28 @@  int nfp_bpf_event_output(struct nfp_app_bpf *bpf, const void *data,
 	return 0;
 }
 
+bool nfp_bpf_offload_check_mtu(struct nfp_net *nn, struct bpf_prog *prog,
+			       unsigned int mtu)
+{
+	unsigned int fw_mtu, pkt_off;
+
+	fw_mtu = nn_readb(nn, NFP_NET_CFG_BPF_INL_MTU) * 64 - 32;
+	pkt_off = min(prog->aux->max_pkt_offset, mtu);
+
+	return fw_mtu < pkt_off;
+}
+
 static int
 nfp_net_bpf_load(struct nfp_net *nn, struct bpf_prog *prog,
 		 struct netlink_ext_ack *extack)
 {
 	struct nfp_prog *nfp_prog = prog->aux->offload->dev_priv;
-	unsigned int fw_mtu, pkt_off, max_stack, max_prog_len;
+	unsigned int max_stack, max_prog_len;
 	dma_addr_t dma_addr;
 	void *img;
 	int err;
 
-	fw_mtu = nn_readb(nn, NFP_NET_CFG_BPF_INL_MTU) * 64 - 32;
-	pkt_off = min(prog->aux->max_pkt_offset, nn->dp.netdev->mtu);
-	if (fw_mtu < pkt_off) {
+	if (nfp_bpf_offload_check_mtu(nn, prog, nn->dp.netdev->mtu)) {
 		NL_SET_ERR_MSG_MOD(extack, "BPF offload not supported with potential packet access beyond HW packet split boundary");
 		return -EOPNOTSUPP;
 	}