[dpdk-dev] [PATCH v6 05/12] linuxapp/eal_pci: get iommu class

[Santosh Shukla <santosh.shukla@caviumnetworks.com>]

Get iommu class of PCI device on the bus and returns preferred iova
mapping mode for that bus.

Algorithm for iova scheme selection for PCI bus:
0. If no device bound then return with RTE_IOVA_DC mapping mode,
else goto 1).
1. Look for device attached to vfio kdrv and has .drv_flag set
to RTE_PCI_DRV_IOVA_AS_VA.
2. Look for any device attached to UIO class of driver.
3. Check for vfio-noiommu mode enabled.

If 2) & 3) is false and 1) is true then select
mapping scheme as RTE_IOVA_VA. Otherwise use default
mapping scheme (RTE_IOVA_PA).

Signed-off-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
---
 lib/librte_eal/linuxapp/eal/eal_pci.c           | 95 +++++++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal_vfio.c          | 19 +++++
 lib/librte_eal/linuxapp/eal/eal_vfio.h          |  4 ++
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 4 files changed, 119 insertions(+)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index 8951ce742..9725fd493 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -45,6 +45,7 @@
 #include "eal_filesystem.h"
 #include "eal_private.h"
 #include "eal_pci_init.h"
+#include "eal_vfio.h"
 
 /**
  * @file
@@ -487,6 +488,100 @@ rte_pci_scan(void)
 	return -1;
 }
 
+/*
+ * Is pci device bound to any kdrv
+ */
+static inline int
+pci_device_is_bound(void)
+{
+	struct rte_pci_device *dev = NULL;
+	int ret = 0;
+
+	FOREACH_DEVICE_ON_PCIBUS(dev) {
+		if (dev->kdrv == RTE_KDRV_UNKNOWN ||
+		    dev->kdrv == RTE_KDRV_NONE) {
+			continue;
+		} else {
+			ret = 1;
+			break;
+		}
+	}
+	return ret;
+}
+
+/*
+ * Any one of the device bound to uio
+ */
+static inline int
+pci_device_bound_uio(void)
+{
+	struct rte_pci_device *dev = NULL;
+
+	FOREACH_DEVICE_ON_PCIBUS(dev) {
+		if (dev->kdrv == RTE_KDRV_IGB_UIO ||
+		   dev->kdrv == RTE_KDRV_UIO_GENERIC) {
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/*
+ * Any one of the device has iova as va
+ */
+static inline int
+pci_device_has_iova_va(void)
+{
+	struct rte_pci_device *dev = NULL;
+	struct rte_pci_driver *drv = NULL;
+
+	FOREACH_DRIVER_ON_PCIBUS(drv) {
+		if (drv && drv->drv_flags & RTE_PCI_DRV_IOVA_AS_VA) {
+			FOREACH_DEVICE_ON_PCIBUS(dev) {
+				if (dev->kdrv == RTE_KDRV_VFIO &&
+				    rte_pci_match(drv, dev))
+					return 1;
+			}
+		}
+	}
+	return 0;
+}
+
+/*
+ * Get iommu class of PCI devices on the bus.
+ */
+enum rte_iova_mode
+rte_pci_get_iommu_class(void)
+{
+	bool is_bound;
+	bool is_vfio_noiommu_enabled = true;
+	bool has_iova_va;
+	bool is_bound_uio;
+
+	is_bound = pci_device_is_bound();
+	if (!is_bound)
+		return RTE_IOVA_DC;
+
+	has_iova_va = pci_device_has_iova_va();
+	is_bound_uio = pci_device_bound_uio();
+#ifdef VFIO_PRESENT
+	is_vfio_noiommu_enabled = vfio_noiommu_is_enabled() == 1 ? 1 : 0;
+#endif
+
+	if (has_iova_va && !is_bound_uio && !is_vfio_noiommu_enabled)
+		return RTE_IOVA_VA;
+
+	if (has_iova_va) {
+		RTE_LOG(WARNING, EAL, "Some devices want iova as va but pa will be used because.. ");
+		if (is_vfio_noiommu_enabled)
+			RTE_LOG(WARNING, EAL, "vfio-noiommu mode configured\n");
+		if (is_bound_uio)
+			RTE_LOG(WARNING, EAL, "few device bound to UIO\n");
+	}
+
+	return RTE_IOVA_PA;
+}
+
 /* Read PCI config space. */
 int rte_pci_read_config(const struct rte_pci_device *device,
 		void *buf, size_t len, off_t offset)
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
index 946df7e31..c8a97b7e7 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
@@ -816,4 +816,23 @@ vfio_noiommu_dma_map(int __rte_unused vfio_container_fd)
 	return 0;
 }
 
+int
+vfio_noiommu_is_enabled(void)
+{
+	int fd, ret, cnt __rte_unused;
+	char c;
+
+	ret = -1;
+	fd = open(VFIO_NOIOMMU_MODE, O_RDONLY);
+	if (fd < 0)
+		return -1;
+
+	cnt = read(fd, &c, 1);
+	if (c == 'Y')
+		ret = 1;
+
+	close(fd);
+	return ret;
+}
+
 #endif
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.h b/lib/librte_eal/linuxapp/eal/eal_vfio.h
index 5ff63e5d7..26ea8e119 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio.h
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio.h
@@ -150,6 +150,8 @@ struct vfio_config {
 #define VFIO_NOIOMMU_GROUP_FMT "/dev/vfio/noiommu-%u"
 #define VFIO_GET_REGION_ADDR(x) ((uint64_t) x << 40ULL)
 #define VFIO_GET_REGION_IDX(x) (x >> 40)
+#define VFIO_NOIOMMU_MODE      \
+	"/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
 
 /* DMA mapping function prototype.
  * Takes VFIO container fd as a parameter.
@@ -210,6 +212,8 @@ int pci_vfio_is_enabled(void);
 
 int vfio_mp_sync_setup(void);
 
+int vfio_noiommu_is_enabled(void);
+
 #define SOCKET_REQ_CONTAINER 0x100
 #define SOCKET_REQ_GROUP 0x200
 #define SOCKET_CLR_GROUP 0x300
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index a15b382ff..40420ded3 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -247,5 +247,6 @@ DPDK_17.11 {
 	global:
 
 	rte_pci_match;
+	rte_pci_get_iommu_class;
 
 } DPDK_17.08;
-- 
2.11.0