[dpdk-dev] [PATCH v4] kni: add IOVA va support for kni

[<kirankumark@marvell.com>]

From: Kiran Kumar K <kirankumark@marvell.com>

With current KNI implementation kernel module will work only in
IOVA=PA mode. This patch will add support for kernel module to work
with IOVA=VA mode.

The idea is to get the physical address from iova address using
api iommu_iova_to_phys. Using this API, we will get the physical
address from iova address and later use phys_to_virt API to
convert the physical address to kernel virtual address.

With this approach we have compared the performance with IOVA=PA
and there is no difference observed. Seems like kernel is the
overhead.

This approach will not work with the kernel versions less than 4.4.0
because of API compatibility issues.

Signed-off-by: Kiran Kumar K <kirankumark@marvell.com>
---
V4 changes:
* Fixed build issues with older kernel versions
* This approach will only work with kernel above 4.4.0


V3 Changes:
* Add new approach to work kni with IOVA=VA mode using
iommu_iova_to_phys API.

 kernel/linux/kni/kni_dev.h                    |  4 +
 kernel/linux/kni/kni_misc.c                   | 63 ++++++++++++---
 kernel/linux/kni/kni_net.c                    | 76 +++++++++++++++----
 lib/librte_eal/linux/eal/eal.c                |  9 ---
 .../linux/eal/include/rte_kni_common.h        |  1 +
 lib/librte_kni/rte_kni.c                      |  2 +
 6 files changed, 122 insertions(+), 33 deletions(-)

diff --git a/kernel/linux/kni/kni_dev.h b/kernel/linux/kni/kni_dev.h
index df46aa70e..9c4944921 100644
--- a/kernel/linux/kni/kni_dev.h
+++ b/kernel/linux/kni/kni_dev.h
@@ -23,6 +23,7 @@
 #include <linux/netdevice.h>
 #include <linux/spinlock.h>
 #include <linux/list.h>
+#include <linux/iommu.h>

 #include <rte_kni_common.h>
 #define KNI_KTHREAD_RESCHEDULE_INTERVAL 5 /* us */
@@ -39,6 +40,9 @@ struct kni_dev {
 	/* kni list */
 	struct list_head list;

+	uint8_t iova_mode;
+	struct iommu_domain *domain;
+
 	struct net_device_stats stats;
 	int status;
 	uint16_t group_id;           /* Group ID of a group of KNI devices */
diff --git a/kernel/linux/kni/kni_misc.c b/kernel/linux/kni/kni_misc.c
index 31845e10f..9e90af31b 100644
--- a/kernel/linux/kni/kni_misc.c
+++ b/kernel/linux/kni/kni_misc.c
@@ -306,10 +306,12 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 	struct rte_kni_device_info dev_info;
 	struct net_device *net_dev = NULL;
 	struct kni_dev *kni, *dev, *n;
+	struct pci_dev *pci = NULL;
+	struct iommu_domain *domain = NULL;
+	phys_addr_t phys_addr;
 #ifdef RTE_KNI_KMOD_ETHTOOL
 	struct pci_dev *found_pci = NULL;
 	struct net_device *lad_dev = NULL;
-	struct pci_dev *pci = NULL;
 #endif

 	pr_info("Creating kni...\n");
@@ -368,15 +370,56 @@ kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 	strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);

 	/* Translate user space info into kernel space info */
-	kni->tx_q = phys_to_virt(dev_info.tx_phys);
-	kni->rx_q = phys_to_virt(dev_info.rx_phys);
-	kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
-	kni->free_q = phys_to_virt(dev_info.free_phys);
-
-	kni->req_q = phys_to_virt(dev_info.req_phys);
-	kni->resp_q = phys_to_virt(dev_info.resp_phys);
-	kni->sync_va = dev_info.sync_va;
-	kni->sync_kva = phys_to_virt(dev_info.sync_phys);
+
+	if (dev_info.iova_mode) {
+#if KERNEL_VERSION(4, 4, 0) > LINUX_VERSION_CODE
+		(void)pci;
+		pr_err("Kernel version is not supported\n");
+		return -EINVAL;
+#else
+		pci = pci_get_device(dev_info.vendor_id,
+				     dev_info.device_id, NULL);
+		while (pci) {
+			if ((pci->bus->number == dev_info.bus) &&
+			    (PCI_SLOT(pci->devfn) == dev_info.devid) &&
+			    (PCI_FUNC(pci->devfn) == dev_info.function)) {
+				domain = iommu_get_domain_for_dev(&pci->dev);
+				break;
+			}
+			pci = pci_get_device(dev_info.vendor_id,
+					     dev_info.device_id, pci);
+		}
+#endif
+		kni->domain = domain;
+		phys_addr = iommu_iova_to_phys(domain, dev_info.tx_phys);
+		kni->tx_q = phys_to_virt(phys_addr);
+		phys_addr = iommu_iova_to_phys(domain, dev_info.rx_phys);
+		kni->rx_q = phys_to_virt(phys_addr);
+		phys_addr = iommu_iova_to_phys(domain, dev_info.alloc_phys);
+		kni->alloc_q = phys_to_virt(phys_addr);
+		phys_addr = iommu_iova_to_phys(domain, dev_info.free_phys);
+		kni->free_q = phys_to_virt(phys_addr);
+		phys_addr = iommu_iova_to_phys(domain, dev_info.req_phys);
+		kni->req_q = phys_to_virt(phys_addr);
+		phys_addr = iommu_iova_to_phys(domain, dev_info.resp_phys);
+		kni->resp_q = phys_to_virt(phys_addr);
+		kni->sync_va = dev_info.sync_va;
+		phys_addr = iommu_iova_to_phys(domain, dev_info.sync_phys);
+		kni->sync_kva = phys_to_virt(phys_addr);
+		kni->iova_mode = 1;
+
+	} else {
+		kni->tx_q = phys_to_virt(dev_info.tx_phys);
+		kni->rx_q = phys_to_virt(dev_info.rx_phys);
+		kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
+		kni->free_q = phys_to_virt(dev_info.free_phys);
+
+		kni->req_q = phys_to_virt(dev_info.req_phys);
+		kni->resp_q = phys_to_virt(dev_info.resp_phys);
+		kni->sync_va = dev_info.sync_va;
+		kni->sync_kva = phys_to_virt(dev_info.sync_phys);
+		kni->iova_mode = 0;
+	}

 	kni->mbuf_size = dev_info.mbuf_size;

diff --git a/kernel/linux/kni/kni_net.c b/kernel/linux/kni/kni_net.c
index be9e6b0b9..4d07ba576 100644
--- a/kernel/linux/kni/kni_net.c
+++ b/kernel/linux/kni/kni_net.c
@@ -35,6 +35,22 @@ static void kni_net_rx_normal(struct kni_dev *kni);
 /* kni rx function pointer, with default to normal rx */
 static kni_net_rx_t kni_net_rx_func = kni_net_rx_normal;

+/* iova to kernel virtual address */
+static void *
+iova2kva(struct kni_dev *kni, void *pa)
+{
+	return phys_to_virt(iommu_iova_to_phys(kni->domain,
+				(dma_addr_t)pa));
+}
+
+static void *
+iova2data_kva(struct kni_dev *kni, struct rte_kni_mbuf *m)
+{
+	return phys_to_virt((iommu_iova_to_phys(kni->domain,
+					(dma_addr_t)m->buf_physaddr) +
+			     m->data_off));
+}
+
 /* physical address to kernel virtual address */
 static void *
 pa2kva(void *pa)
@@ -186,7 +202,10 @@ kni_fifo_trans_pa2va(struct kni_dev *kni,
 			return;

 		for (i = 0; i < num_rx; i++) {
-			kva = pa2kva(kni->pa[i]);
+			if (likely(kni->iova_mode == 1))
+				kva = iova2kva(kni, kni->pa[i]);
+			else
+				kva = pa2kva(kni->pa[i]);
 			kni->va[i] = pa2va(kni->pa[i], kva);
 		}

@@ -263,8 +282,13 @@ kni_net_tx(struct sk_buff *skb, struct net_device *dev)
 	if (likely(ret == 1)) {
 		void *data_kva;

-		pkt_kva = pa2kva(pkt_pa);
-		data_kva = kva2data_kva(pkt_kva);
+		if (likely(kni->iova_mode == 1)) {
+			pkt_kva = iova2kva(kni, pkt_pa);
+			data_kva = iova2data_kva(kni, pkt_kva);
+		} else {
+			pkt_kva = pa2kva(pkt_pa);
+			data_kva = kva2data_kva(pkt_kva);
+		}
 		pkt_va = pa2va(pkt_pa, pkt_kva);

 		len = skb->len;
@@ -335,9 +359,14 @@ kni_net_rx_normal(struct kni_dev *kni)

 	/* Transfer received packets to netif */
 	for (i = 0; i < num_rx; i++) {
-		kva = pa2kva(kni->pa[i]);
+		if (likely(kni->iova_mode == 1)) {
+			kva = iova2kva(kni, kni->pa[i]);
+			data_kva = iova2data_kva(kni, kva);
+		} else {
+			kva = pa2kva(kni->pa[i]);
+			data_kva = kva2data_kva(kva);
+		}
 		len = kva->pkt_len;
-		data_kva = kva2data_kva(kva);
 		kni->va[i] = pa2va(kni->pa[i], kva);

 		skb = dev_alloc_skb(len + 2);
@@ -434,13 +463,20 @@ kni_net_rx_lo_fifo(struct kni_dev *kni)
 		num = ret;
 		/* Copy mbufs */
 		for (i = 0; i < num; i++) {
-			kva = pa2kva(kni->pa[i]);
+
+			if (likely(kni->iova_mode == 1)) {
+				kva = iova2kva(kni, kni->pa[i]);
+				data_kva = iova2data_kva(kni, kva);
+				alloc_kva = iova2kva(kni, kni->alloc_pa[i]);
+				alloc_data_kva = iova2data_kva(kni, alloc_kva);
+			} else {
+				kva = pa2kva(kni->pa[i]);
+				data_kva = kva2data_kva(kva);
+				alloc_kva = pa2kva(kni->alloc_pa[i]);
+				alloc_data_kva = kva2data_kva(alloc_kva);
+			}
 			len = kva->pkt_len;
-			data_kva = kva2data_kva(kva);
 			kni->va[i] = pa2va(kni->pa[i], kva);
-
-			alloc_kva = pa2kva(kni->alloc_pa[i]);
-			alloc_data_kva = kva2data_kva(alloc_kva);
 			kni->alloc_va[i] = pa2va(kni->alloc_pa[i], alloc_kva);

 			memcpy(alloc_data_kva, data_kva, len);
@@ -507,9 +543,15 @@ kni_net_rx_lo_fifo_skb(struct kni_dev *kni)

 	/* Copy mbufs to sk buffer and then call tx interface */
 	for (i = 0; i < num; i++) {
-		kva = pa2kva(kni->pa[i]);
+
+		if (likely(kni->iova_mode == 1)) {
+			kva = iova2kva(kni, kni->pa[i]);
+			data_kva = iova2data_kva(kni, kva);
+		} else {
+			kva = pa2kva(kni->pa[i]);
+			data_kva = kva2data_kva(kva);
+		}
 		len = kva->pkt_len;
-		data_kva = kva2data_kva(kva);
 		kni->va[i] = pa2va(kni->pa[i], kva);

 		skb = dev_alloc_skb(len + 2);
@@ -545,8 +587,14 @@ kni_net_rx_lo_fifo_skb(struct kni_dev *kni)
 				if (!kva->next)
 					break;

-				kva = pa2kva(va2pa(kva->next, kva));
-				data_kva = kva2data_kva(kva);
+				if (likely(kni->iova_mode == 1)) {
+					kva = iova2kva(kni,
+						       va2pa(kva->next, kva));
+					data_kva = iova2data_kva(kni, kva);
+				} else {
+					kva = pa2kva(va2pa(kva->next, kva));
+					data_kva = kva2data_kva(kva);
+				}
 			}
 		}

diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c
index f7ae62d7b..8fac6707d 100644
--- a/lib/librte_eal/linux/eal/eal.c
+++ b/lib/librte_eal/linux/eal/eal.c
@@ -1040,15 +1040,6 @@ rte_eal_init(int argc, char **argv)
 		/* autodetect the IOVA mapping mode (default is RTE_IOVA_PA) */
 		rte_eal_get_configuration()->iova_mode =
 			rte_bus_get_iommu_class();
-
-		/* Workaround for KNI which requires physical address to work */
-		if (rte_eal_get_configuration()->iova_mode == RTE_IOVA_VA &&
-				rte_eal_check_module("rte_kni") == 1) {
-			rte_eal_get_configuration()->iova_mode = RTE_IOVA_PA;
-			RTE_LOG(WARNING, EAL,
-				"Some devices want IOVA as VA but PA will be used because.. "
-				"KNI module inserted\n");
-		}
 	} else {
 		rte_eal_get_configuration()->iova_mode =
 			internal_config.iova_mode;
diff --git a/lib/librte_eal/linux/eal/include/rte_kni_common.h b/lib/librte_eal/linux/eal/include/rte_kni_common.h
index 5afa08713..79ee4bc5a 100644
--- a/lib/librte_eal/linux/eal/include/rte_kni_common.h
+++ b/lib/librte_eal/linux/eal/include/rte_kni_common.h
@@ -128,6 +128,7 @@ struct rte_kni_device_info {
 	unsigned mbuf_size;
 	unsigned int mtu;
 	char mac_addr[6];
+	uint8_t iova_mode;
 };

 #define KNI_DEVICE "kni"
diff --git a/lib/librte_kni/rte_kni.c b/lib/librte_kni/rte_kni.c
index 946459c79..ec8f23694 100644
--- a/lib/librte_kni/rte_kni.c
+++ b/lib/librte_kni/rte_kni.c
@@ -304,6 +304,8 @@ rte_kni_alloc(struct rte_mempool *pktmbuf_pool,
 	kni->group_id = conf->group_id;
 	kni->mbuf_size = conf->mbuf_size;

+	dev_info.iova_mode = (rte_eal_iova_mode() == RTE_IOVA_VA) ? 1 : 0;
+
 	ret = ioctl(kni_fd, RTE_KNI_IOCTL_CREATE, &dev_info);
 	if (ret < 0)
 		goto ioctl_fail;
--
2.17.1