Set a 64-bit DMA mask and UINT_MAX max segment size on nsim_bus_dev in nsim_bus_probe() when direct DMA mapping is supported, enable NETMEM_TX_DMA on the netdevsim net_device, and configure page_pool instances with PP_FLAG_ALLOW_UNREADABLE_NETMEM and queue_idx, plus PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV when a DMA mask and PP_DMA_INDEX_BITS are available, so devmem bind-rx and bind-tx netlink operations can be tested against netdevsim in software selftests.
The pp_hold debugfs file allocates pages from the queue 0 page pool, so refuse it when that pool is absent or backed by a memory provider, and take the netdev instance lock there so a concurrent bind-rx cannot swap the pool in between. Since netdevsim forwards TX skbs in software without a DMA engine, drop unreadable or net_iov skbs in nsim_start_xmit(). Cc: Tariq Toukan <[email protected]> Cc: Kaifeng Wang <[email protected]> Signed-off-by: Mina Almasry <[email protected]> Reviewed-by: Dragos Tatulea <[email protected]> Acked-by: Stanislav Fomichev <[email protected]> --- v5: - Configure the DMA mask and dma_parms in nsim_bus_probe() gated on dma_pci_p2pdma_supported(), and require PP_DMA_INDEX_BITS before setting PP_FLAG_DMA_MAP so page_pool_scrub() can unmap inflight pages on 32-bit builds (Sashiko). - Check for NULL ns->rq in nsim_pp_hold_write() and drop unreadable or net_iov skbs at the start of nsim_start_xmit() (Sashiko). v3: - Only request page pool DMA mapping when CONFIG_HAS_DMA is set (Sashiko). - Refuse pp_hold on a page pool backed by a memory provider, under the netdev instance lock (Sashiko). - Drop unreadable skbs in the software PSP path when it would have to checksum the payload (Sashiko). --- drivers/net/netdevsim/bus.c | 9 +++++++++ drivers/net/netdevsim/netdev.c | 33 +++++++++++++++++++++++++------ drivers/net/netdevsim/netdevsim.h | 1 + 3 files changed, 37 insertions(+), 6 deletions(-) diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c index b792ee10b1c1a..5f8f0c2f76939 100644 --- a/drivers/net/netdevsim/bus.c +++ b/drivers/net/netdevsim/bus.c @@ -5,6 +5,7 @@ #include <linux/completion.h> #include <linux/device.h> +#include <linux/dma-mapping.h> #include <linux/idr.h> #include <linux/kernel.h> #include <linux/list.h> @@ -416,6 +417,14 @@ static int nsim_bus_probe(struct device *dev) { struct nsim_bus_dev *nsim_bus_dev = to_nsim_bus_dev(dev); + if (dma_pci_p2pdma_supported(dev) && + !dma_coerce_mask_and_coherent(dev, DMA_BIT_MASK(64))) { + dev->dma_parms = &nsim_bus_dev->dma_parms; + dma_set_max_seg_size(dev, UINT_MAX); + } else { + dev->dma_mask = NULL; + } + return nsim_drv_probe(nsim_bus_dev); } diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c index eebc02ccc4a92..0372a9bd63bbb 100644 --- a/drivers/net/netdevsim/netdev.c +++ b/drivers/net/netdevsim/netdev.c @@ -133,6 +133,10 @@ static netdev_tx_t nsim_start_xmit(struct sk_buff *skb, struct net_device *dev) int dr; rcu_read_lock(); + if (!skb_frags_readable(skb) || + (skb_shinfo(skb)->nr_frags && + skb_frag_is_net_iov(&skb_shinfo(skb)->frags[0]))) + goto out_drop_any; if (!nsim_ipsec_tx(ns, skb)) goto out_drop_any; @@ -422,19 +426,27 @@ static int nsim_poll(struct napi_struct *napi, int budget) return done; } -static int nsim_create_page_pool(struct page_pool **p, struct napi_struct *napi) +static int nsim_create_page_pool(struct net_device *dev, struct page_pool **p, + struct napi_struct *napi, int idx) { + struct netdevsim *ns = netdev_priv(dev); struct page_pool_params params = { .order = 0, .pool_size = NSIM_RING_SIZE, + .flags = PP_FLAG_ALLOW_UNREADABLE_NETMEM, + .max_len = PAGE_SIZE, .nid = NUMA_NO_NODE, - .dev = &napi->dev->dev, + .dev = &ns->nsim_bus_dev->dev, .napi = napi, .dma_dir = DMA_BIDIRECTIONAL, - .netdev = napi->dev, + .netdev = dev, + .queue_idx = idx, }; struct page_pool *pool; + if (ns->nsim_bus_dev->dev.dma_mask && PP_DMA_INDEX_BITS) + params.flags |= PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV; + pool = page_pool_create(¶ms); if (IS_ERR(pool)) return PTR_ERR(pool); @@ -458,7 +470,7 @@ static int nsim_init_napi(struct netdevsim *ns) for (i = 0; i < dev->num_rx_queues; i++) { rq = ns->rq[i]; - err = nsim_create_page_pool(&rq->page_pool, &rq->napi); + err = nsim_create_page_pool(dev, &rq->page_pool, &rq->napi, i); if (err) goto err_pp_destroy; } @@ -770,14 +782,16 @@ nsim_queue_mem_alloc(struct net_device *dev, if (ns->rq_reset_mode == 1) { if (!netif_running(ns->netdev)) return -ENETDOWN; - return nsim_create_page_pool(&qmem->pp, &ns->rq[idx]->napi); + return nsim_create_page_pool(dev, &qmem->pp, + &ns->rq[idx]->napi, idx); } qmem->rq = nsim_queue_alloc(); if (!qmem->rq) return -ENOMEM; - err = nsim_create_page_pool(&qmem->rq->page_pool, &qmem->rq->napi); + err = nsim_create_page_pool(dev, &qmem->rq->page_pool, &qmem->rq->napi, + idx); if (err) goto err_free; @@ -937,12 +951,16 @@ nsim_pp_hold_write(struct file *file, const char __user *data, return ret; rtnl_lock(); + netdev_lock(ns->netdev); ret = count; if (val == !!ns->page) goto exit; if (!netif_running(ns->netdev) && val) { ret = -ENETDOWN; + } else if (val && (!ns->rq || + page_pool_is_unreadable(ns->rq[0]->page_pool))) { + ret = -EOPNOTSUPP; } else if (val) { ns->page = page_pool_dev_alloc_pages(ns->rq[0]->page_pool); if (!ns->page) @@ -954,6 +972,7 @@ nsim_pp_hold_write(struct file *file, const char __user *data, } exit: + netdev_unlock(ns->netdev); rtnl_unlock(); return ret; } @@ -1059,6 +1078,8 @@ static int nsim_init_netdevsim(struct netdevsim *ns) ns->netdev->netdev_ops = &nsim_netdev_ops; ns->netdev->stat_ops = &nsim_stat_ops; ns->netdev->queue_mgmt_ops = &nsim_queue_mgmt_ops; + if (ns->nsim_bus_dev->dev.dma_mask) + ns->netdev->netmem_tx = NETMEM_TX_DMA; netdev_lockdep_set_classes(ns->netdev); err = nsim_udp_tunnels_info_create(ns->nsim_dev, ns->netdev); diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h index fd5599cd3bb9f..2aa7ea924396e 100644 --- a/drivers/net/netdevsim/netdevsim.h +++ b/drivers/net/netdevsim/netdevsim.h @@ -476,6 +476,7 @@ int nsim_setup_tc(struct net_device *dev, enum tc_setup_type type, #define NSIM_BUS_DEV_MAX_VFS 4 struct nsim_bus_dev { struct device dev; + struct device_dma_parameters dma_parms; struct list_head list; unsigned int port_count; unsigned int num_queues; /* Number of queues for each port on this bus */ -- 2.56.0.385.gac671c819a-goog
