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Message-ID: <ZKwohzanCVIFwrxN@lincoln>
Date: Mon, 10 Jul 2023 17:49:27 +0200
From: Larysa Zaremba <larysa.zaremba@...el.com>
To: Stanislav Fomichev <sdf@...gle.com>
CC: <bpf@...r.kernel.org>, <ast@...nel.org>, <daniel@...earbox.net>,
<andrii@...nel.org>, <martin.lau@...ux.dev>, <song@...nel.org>, <yhs@...com>,
<john.fastabend@...il.com>, <kpsingh@...nel.org>, <haoluo@...gle.com>,
<jolsa@...nel.org>, David Ahern <dsahern@...il.com>, Jakub Kicinski
<kuba@...nel.org>, Willem de Bruijn <willemb@...gle.com>, "Jesper Dangaard
Brouer" <brouer@...hat.com>, Anatoly Burakov <anatoly.burakov@...el.com>,
Alexander Lobakin <alexandr.lobakin@...el.com>, Magnus Karlsson
<magnus.karlsson@...il.com>, Maryam Tahhan <mtahhan@...hat.com>,
<xdp-hints@...-project.net>, <netdev@...r.kernel.org>
Subject: Re: [PATCH bpf-next v2 06/20] ice: Support HW timestamp hint
On Thu, Jul 06, 2023 at 09:39:29AM -0700, Stanislav Fomichev wrote:
> On Thu, Jul 6, 2023 at 7:27 AM Larysa Zaremba <larysa.zaremba@...el.com> wrote:
> >
> > On Wed, Jul 05, 2023 at 10:30:56AM -0700, Stanislav Fomichev wrote:
> > > On 07/03, Larysa Zaremba wrote:
> > > > Use previously refactored code and create a function
> > > > that allows XDP code to read HW timestamp.
> > > >
> > > > Also, move cached_phctime into packet context, this way this data still
> > > > stays in the ring structure, just at the different address.
> > > >
> > > > HW timestamp is the first supported hint in the driver,
> > > > so also add xdp_metadata_ops.
> > > >
> > > > Signed-off-by: Larysa Zaremba <larysa.zaremba@...el.com>
> > > > ---
> > > > drivers/net/ethernet/intel/ice/ice.h | 2 ++
> > > > drivers/net/ethernet/intel/ice/ice_ethtool.c | 2 +-
> > > > drivers/net/ethernet/intel/ice/ice_lib.c | 2 +-
> > > > drivers/net/ethernet/intel/ice/ice_main.c | 1 +
> > > > drivers/net/ethernet/intel/ice/ice_ptp.c | 2 +-
> > > > drivers/net/ethernet/intel/ice/ice_txrx.h | 2 +-
> > > > drivers/net/ethernet/intel/ice/ice_txrx_lib.c | 24 +++++++++++++++++++
> > > > 7 files changed, 31 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice.h b/drivers/net/ethernet/intel/ice/ice.h
> > > > index 4ba3d99439a0..7a973a2229f1 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice.h
> > > > +++ b/drivers/net/ethernet/intel/ice/ice.h
> > > > @@ -943,4 +943,6 @@ static inline void ice_clear_rdma_cap(struct ice_pf *pf)
> > > > set_bit(ICE_FLAG_UNPLUG_AUX_DEV, pf->flags);
> > > > clear_bit(ICE_FLAG_RDMA_ENA, pf->flags);
> > > > }
> > > > +
> > > > +extern const struct xdp_metadata_ops ice_xdp_md_ops;
> > > > #endif /* _ICE_H_ */
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_ethtool.c b/drivers/net/ethernet/intel/ice/ice_ethtool.c
> > > > index 8d5cbbd0b3d5..3c3b9cbfbcd3 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_ethtool.c
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_ethtool.c
> > > > @@ -2837,7 +2837,7 @@ ice_set_ringparam(struct net_device *netdev, struct ethtool_ringparam *ring,
> > > > /* clone ring and setup updated count */
> > > > rx_rings[i] = *vsi->rx_rings[i];
> > > > rx_rings[i].count = new_rx_cnt;
> > > > - rx_rings[i].cached_phctime = pf->ptp.cached_phc_time;
> > > > + rx_rings[i].pkt_ctx.cached_phctime = pf->ptp.cached_phc_time;
> > > > rx_rings[i].desc = NULL;
> > > > rx_rings[i].rx_buf = NULL;
> > > > /* this is to allow wr32 to have something to write to
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
> > > > index 00e3afd507a4..eb69b0ac7956 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_lib.c
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_lib.c
> > > > @@ -1445,7 +1445,7 @@ static int ice_vsi_alloc_rings(struct ice_vsi *vsi)
> > > > ring->netdev = vsi->netdev;
> > > > ring->dev = dev;
> > > > ring->count = vsi->num_rx_desc;
> > > > - ring->cached_phctime = pf->ptp.cached_phc_time;
> > > > + ring->pkt_ctx.cached_phctime = pf->ptp.cached_phc_time;
> > > > WRITE_ONCE(vsi->rx_rings[i], ring);
> > > > }
> > > >
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
> > > > index 93979ab18bc1..f21996b812ea 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_main.c
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_main.c
> > > > @@ -3384,6 +3384,7 @@ static void ice_set_ops(struct ice_vsi *vsi)
> > > >
> > > > netdev->netdev_ops = &ice_netdev_ops;
> > > > netdev->udp_tunnel_nic_info = &pf->hw.udp_tunnel_nic;
> > > > + netdev->xdp_metadata_ops = &ice_xdp_md_ops;
> > > > ice_set_ethtool_ops(netdev);
> > > >
> > > > if (vsi->type != ICE_VSI_PF)
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> > > > index a31333972c68..70697e4829dd 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> > > > @@ -1038,7 +1038,7 @@ static int ice_ptp_update_cached_phctime(struct ice_pf *pf)
> > > > ice_for_each_rxq(vsi, j) {
> > > > if (!vsi->rx_rings[j])
> > > > continue;
> > > > - WRITE_ONCE(vsi->rx_rings[j]->cached_phctime, systime);
> > > > + WRITE_ONCE(vsi->rx_rings[j]->pkt_ctx.cached_phctime, systime);
> > > > }
> > > > }
> > > > clear_bit(ICE_CFG_BUSY, pf->state);
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
> > > > index d0ab2c4c0c91..4237702a58a9 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_txrx.h
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
> > > > @@ -259,6 +259,7 @@ enum ice_rx_dtype {
> > > >
> > > > struct ice_pkt_ctx {
> > > > const union ice_32b_rx_flex_desc *eop_desc;
> > > > + u64 cached_phctime;
> > > > };
> > > >
> > > > struct ice_xdp_buff {
> > > > @@ -354,7 +355,6 @@ struct ice_rx_ring {
> > > > struct ice_tx_ring *xdp_ring;
> > > > struct xsk_buff_pool *xsk_pool;
> > > > dma_addr_t dma; /* physical address of ring */
> > > > - u64 cached_phctime;
> > > > u16 rx_buf_len;
> > > > u8 dcb_tc; /* Traffic class of ring */
> > > > u8 ptp_rx;
> > > > diff --git a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> > > > index beb1c5bb392a..463d9e5cbe05 100644
> > > > --- a/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> > > > +++ b/drivers/net/ethernet/intel/ice/ice_txrx_lib.c
> > > > @@ -546,3 +546,27 @@ void ice_finalize_xdp_rx(struct ice_tx_ring *xdp_ring, unsigned int xdp_res,
> > > > spin_unlock(&xdp_ring->tx_lock);
> > > > }
> > > > }
> > > > +
> > > > +/**
> > > > + * ice_xdp_rx_hw_ts - HW timestamp XDP hint handler
> > > > + * @ctx: XDP buff pointer
> > > > + * @ts_ns: destination address
> > > > + *
> > > > + * Copy HW timestamp (if available) to the destination address.
> > > > + */
> > > > +static int ice_xdp_rx_hw_ts(const struct xdp_md *ctx, u64 *ts_ns)
> > > > +{
> > > > + const struct ice_xdp_buff *xdp_ext = (void *)ctx;
> > > > + u64 cached_time;
> > > > +
> > > > + cached_time = READ_ONCE(xdp_ext->pkt_ctx.cached_phctime);
> > >
> > > I believe we have to have something like the following here:
> > >
> > > if (!ts_ns)
> > > return -EINVAL;
> > >
> > > IOW, I don't think verifier guarantees that those pointer args are
> > > non-NULL.
> >
> > Oh, that's a shame.
> >
> > > Same for the other ice kfunc you're adding and veth changes.
> > >
> > > Can you also fix it for the existing veth kfuncs? (or lmk if you prefer me
> > > to fix it).
> >
> > I think I can send fixes for RX hash and timestamp in veth separately, before
> > v3 of this patchset, code probably doesn't intersect.
> >
> > But argument checks in kfuncs are a little bit a gray area for me, whether they
> > should be sent to stable tree or not?
>
> Add a Fixes tag and they will get into the stable trees automatically I believe?
What about declaring XDP hints kfuncs with
BTF_ID_FLAGS(func, name, KF_TRUSTED_ARGS)
instead of BTF_ID_FLAGS(func, name, 0)
?
I have tested this just now and xdp_metadata passes just fine (so both stack
and data_meta destination pointers work), but if I replace ×tamp with NULL,
verifier rejects the program with a descriptive message "Possibly NULL pointer
passed to trusted arg1", so it serves our purpose. I do not see many ways this
could limit the users, but it definitely benefits driver developers.
The only concern I see is that if we ever decide to allow NULL arguments for
kfuncs, we'd need to add support for a "_or_null" suffix [0]. But it doesn't
sound too hard?
I have dug into this, because adding
if (unlikely(!hash || &rss_type))
return -EINVAL;
or something similar to every .xmo_ handler in existence starts to look ugly.
[0]
https://lore.kernel.org/lkml/20230120054441.arj5h6yrnh5jsrgr@MacBook-Pro-6.local.dhcp.thefacebook.com/
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