[dpdk-dev] [PATCH] bus/pci: support iova=va on PowerNV systems

[David Christensen <drc@linux.vnet.ibm.com>]

Bare metal PowerNV systems include a DPDK supported IOMMU that allows
IOVA=VA support. Test for the platform type and report virtual address
support if running on a PowerNV system.

Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
---
 drivers/bus/pci/linux/pci.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index 740a2cdad..696dc177e 100644
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -549,6 +549,35 @@ pci_device_iommu_support_va(const struct rte_pci_device *dev)
 bool
 pci_device_iommu_support_va(__rte_unused const struct rte_pci_device *dev)
 {
+	/*
+	 * IOMMU is always present on a PowerNV host (IOMMUv2).
+	 * IOMMU is also present in a KVM/QEMU VM (IOMMUv1) but is not
+	 * currently supported by DPDK. Test for our current environment
+	 * and report VA support as appropriate.
+	 */
+
+	char *line = 0;
+	size_t len = 0;
+	char filename[PATH_MAX] = "/proc/cpuinfo";
+	FILE *fp = fopen(filename, "r");
+
+	if (fp == NULL) {
+		RTE_LOG(ERR, EAL, "%s(): can't open %s: %s\n",
+			__func__, filename, strerror(errno));
+		return false;
+	}
+
+	/* Check for a PowerNV platform */
+	while (getline(&line, &len, fp) != -1) {
+		if (strstr(line, "platform") != NULL)
+			if (strstr(line, "PowerNV") != NULL) {
+				RTE_LOG(DEBUG, EAL, "Running on a PowerNV system\n");
+				fclose(fp);
+				return true;
+			}
+	}
+	fclose(fp);
+
 	return false;
 }
 #else
-- 
2.18.1