From: Ilya Maximets Date: Wed, 9 Jan 2019 14:50:15 +0000 (+0300) Subject: net/virtio: support platform memory ordering X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=9230ab8d791399179498d42dfd84981c5bba412a;p=dpdk.git net/virtio: support platform memory ordering VIRTIO_F_ORDER_PLATFORM is required to use proper memory barriers in case of HW vhost implementations like vDPA. DMA barriers (rte_cio_*) are sufficent for that purpose. Previously known as VIRTIO_F_IO_BARRIER. Signed-off-by: Ilya Maximets Reviewed-by: Maxime Coquelin Acked-by: Michael S. Tsirkin --- diff --git a/drivers/net/virtio/virtio_ethdev.c b/drivers/net/virtio/virtio_ethdev.c index 446c338fcd..6d461180ce 100644 --- a/drivers/net/virtio/virtio_ethdev.c +++ b/drivers/net/virtio/virtio_ethdev.c @@ -1613,6 +1613,8 @@ virtio_init_device(struct rte_eth_dev *eth_dev, uint64_t req_features) if (virtio_negotiate_features(hw, req_features) < 0) return -1; + hw->weak_barriers = !vtpci_with_feature(hw, VIRTIO_F_ORDER_PLATFORM); + if (!hw->virtio_user_dev) { pci_dev = RTE_ETH_DEV_TO_PCI(eth_dev); rte_eth_copy_pci_info(eth_dev, pci_dev); diff --git a/drivers/net/virtio/virtio_ethdev.h b/drivers/net/virtio/virtio_ethdev.h index f8d8a56ab4..b8aab7da44 100644 --- a/drivers/net/virtio/virtio_ethdev.h +++ b/drivers/net/virtio/virtio_ethdev.h @@ -35,7 +35,8 @@ 1ULL << VIRTIO_F_VERSION_1 | \ 1ULL << VIRTIO_F_IN_ORDER | \ 1ULL << VIRTIO_F_RING_PACKED | \ - 1ULL << VIRTIO_F_IOMMU_PLATFORM) + 1ULL << VIRTIO_F_IOMMU_PLATFORM | \ + 1ULL << VIRTIO_F_ORDER_PLATFORM) #define VIRTIO_PMD_SUPPORTED_GUEST_FEATURES \ (VIRTIO_PMD_DEFAULT_GUEST_FEATURES | \ diff --git a/drivers/net/virtio/virtio_pci.h b/drivers/net/virtio/virtio_pci.h index b22b62dad6..38a0261daf 100644 --- a/drivers/net/virtio/virtio_pci.h +++ b/drivers/net/virtio/virtio_pci.h @@ -129,6 +129,12 @@ struct virtnet_ctl; */ #define VIRTIO_F_IN_ORDER 35 +/* + * This feature indicates that memory accesses by the driver and the device + * are ordered in a way described by the platform. + */ +#define VIRTIO_F_ORDER_PLATFORM 36 + /* The Guest publishes the used index for which it expects an interrupt * at the end of the avail ring. Host should ignore the avail->flags field. */ /* The Host publishes the avail index for which it expects a kick @@ -241,6 +247,7 @@ struct virtio_hw { uint8_t use_simple_rx; uint8_t use_inorder_rx; uint8_t use_inorder_tx; + uint8_t weak_barriers; bool has_tx_offload; bool has_rx_offload; uint16_t port_id; diff --git a/drivers/net/virtio/virtio_rxtx.c b/drivers/net/virtio/virtio_rxtx.c index 2309b71d6e..ebb86ef700 100644 --- a/drivers/net/virtio/virtio_rxtx.c +++ b/drivers/net/virtio/virtio_rxtx.c @@ -1152,7 +1152,7 @@ virtio_recv_pkts(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts) nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); num = likely(nb_used <= nb_pkts) ? nb_used : nb_pkts; if (unlikely(num > VIRTIO_MBUF_BURST_SZ)) @@ -1361,7 +1361,7 @@ virtio_recv_pkts_inorder(void *rx_queue, nb_used = RTE_MIN(nb_used, nb_pkts); nb_used = RTE_MIN(nb_used, VIRTIO_MBUF_BURST_SZ); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); PMD_RX_LOG(DEBUG, "used:%d", nb_used); @@ -1549,7 +1549,7 @@ virtio_recv_mergeable_pkts(void *rx_queue, nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); PMD_RX_LOG(DEBUG, "used:%d", nb_used); @@ -1940,7 +1940,7 @@ virtio_xmit_pkts_packed(void *tx_queue, struct rte_mbuf **tx_pkts, /* Positive value indicates it need free vring descriptors */ if (unlikely(need > 0)) { - virtio_rmb(); + virtio_rmb(hw->weak_barriers); need = RTE_MIN(need, (int)nb_pkts); virtio_xmit_cleanup_packed(vq, need); need = slots - vq->vq_free_cnt; @@ -1988,7 +1988,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts); nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh)) virtio_xmit_cleanup(vq, nb_used); @@ -2030,7 +2030,7 @@ virtio_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, uint16_t nb_pkts) /* Positive value indicates it need free vring descriptors */ if (unlikely(need > 0)) { nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); need = RTE_MIN(need, (int)nb_used); virtio_xmit_cleanup(vq, need); @@ -2086,7 +2086,7 @@ virtio_xmit_pkts_inorder(void *tx_queue, PMD_TX_LOG(DEBUG, "%d packets to xmit", nb_pkts); nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); if (likely(nb_used > vq->vq_nentries - vq->vq_free_thresh)) virtio_xmit_cleanup_inorder(vq, nb_used); @@ -2134,7 +2134,7 @@ virtio_xmit_pkts_inorder(void *tx_queue, need = slots - vq->vq_free_cnt; if (unlikely(need > 0)) { nb_used = VIRTQUEUE_NUSED(vq); - virtio_rmb(); + virtio_rmb(hw->weak_barriers); need = RTE_MIN(need, (int)nb_used); virtio_xmit_cleanup_inorder(vq, need); diff --git a/drivers/net/virtio/virtqueue.h b/drivers/net/virtio/virtqueue.h index 53aeac238a..123bec34f2 100644 --- a/drivers/net/virtio/virtqueue.h +++ b/drivers/net/virtio/virtqueue.h @@ -19,15 +19,40 @@ struct rte_mbuf; /* - * Per virtio_config.h in Linux. + * Per virtio_ring.h in Linux. * For virtio_pci on SMP, we don't need to order with respect to MMIO * accesses through relaxed memory I/O windows, so smp_mb() et al are * sufficient. * + * For using virtio to talk to real devices (eg. vDPA) we do need real + * barriers. */ -#define virtio_mb() rte_smp_mb() -#define virtio_rmb() rte_smp_rmb() -#define virtio_wmb() rte_smp_wmb() +static inline void +virtio_mb(uint8_t weak_barriers) +{ + if (weak_barriers) + rte_smp_mb(); + else + rte_mb(); +} + +static inline void +virtio_rmb(uint8_t weak_barriers) +{ + if (weak_barriers) + rte_smp_rmb(); + else + rte_cio_rmb(); +} + +static inline void +virtio_wmb(uint8_t weak_barriers) +{ + if (weak_barriers) + rte_smp_wmb(); + else + rte_cio_wmb(); +} #ifdef RTE_PMD_PACKET_PREFETCH #define rte_packet_prefetch(p) rte_prefetch1(p) @@ -325,7 +350,7 @@ virtqueue_enable_intr_packed(struct virtqueue *vq) if (vq->event_flags_shadow == RING_EVENT_FLAGS_DISABLE) { - virtio_wmb(); + virtio_wmb(vq->hw->weak_barriers); vq->event_flags_shadow = RING_EVENT_FLAGS_ENABLE; *event_flags = vq->event_flags_shadow; } @@ -391,7 +416,7 @@ void vq_ring_free_inorder(struct virtqueue *vq, uint16_t desc_idx, static inline void vq_update_avail_idx(struct virtqueue *vq) { - virtio_wmb(); + virtio_wmb(vq->hw->weak_barriers); vq->vq_ring.avail->idx = vq->vq_avail_idx; } @@ -419,7 +444,7 @@ virtqueue_kick_prepare(struct virtqueue *vq) * Ensure updated avail->idx is visible to vhost before reading * the used->flags. */ - virtio_mb(); + virtio_mb(vq->hw->weak_barriers); return !(vq->vq_ring.used->flags & VRING_USED_F_NO_NOTIFY); } @@ -431,7 +456,7 @@ virtqueue_kick_prepare_packed(struct virtqueue *vq) /* * Ensure updated data is visible to vhost before reading the flags. */ - virtio_mb(); + virtio_mb(vq->hw->weak_barriers); flags = vq->ring_packed.device_event->desc_event_flags; return flags != RING_EVENT_FLAGS_DISABLE;