bus/pci: support IOVA as VA in PowerVM LPARs

Add IOMMU detection logic for PowerVM LPARs.

PowerNV $ cat /proc/cpuinfo
...
timebase     : 512000000
platform     : PowerNV
model        : 8335-GTW

PowerVM LPAR $ cat /proc/cpuinfo
...
timebase     : 512000000
platform     : pSeries
model        : IBM,9009-22A
machine      : CHRP IBM,9009-22A
MMU          : Hash

PowerNV KVM Guest $ cat /proc/cpuinfo
...
timebase     : 512000000
platform     : pSeries
model        : IBM pSeries (emulated by qemu)
machine      : CHRP IBM pSeries (emulated by qemu)
MMU          : Radix

Signed-off-by: David Christensen <drc@linux.vnet.ibm.com>
Reviewed-by: Thinh Tran <thinhtr@linux.vnet.ibm.com>

diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
index edfe430..c2fcc1a 100644 (file)
--- a/drivers/bus/pci/linux/pci.c
+++ b/drivers/bus/pci/linux/pci.c
@@ -549,16 +549,22 @@ 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.
+        * All POWER systems support an IOMMU, but only IOMMUv2 supports
+        * IOVA = VA in DPDK. Check contents of /proc/cpuinfo to find the
+        * system.
+        *
+        * Platform | Model |  IOMMU  | VA? |             Comment
+        * ---------+-------+---------+-----+---------------------------------
+        *  PowerNV |  N/A  | IOMMUv2 | Yes | OpenPOWER (Bare Metal)
+        *  pSeries | ~qemu | IOMMUv2 | Yes | PowerVM Logical Partition (LPAR)
+        *  pSeries |  qemu | IOMMUv1 |  No | QEMU Virtual Machine
         */
 
        char *line = NULL;
        size_t len = 0;
        char filename[PATH_MAX] = "/proc/cpuinfo";
        FILE *fp = fopen(filename, "r");
+       bool pseries = false, powernv = false, qemu = false;
        bool ret = false;
 
        if (fp == NULL) {
@@ -567,20 +573,29 @@ pci_device_iommu_support_va(__rte_unused const struct rte_pci_device *dev)
                return ret;
        }
 
-       /* Check for a PowerNV platform */
+       /* Check the "platform" and "model" fields */
        while (getline(&line, &len, fp) != -1) {
-               if (strstr(line, "platform") == NULL)
-                       continue;
-
-               if (strstr(line, "PowerNV") != NULL) {
-                       RTE_LOG(DEBUG, EAL, "Running on a PowerNV system\n");
-                       ret = true;
-                       break;
+               if (strstr(line, "platform") != NULL) {
+                       if (strstr(line, "PowerNV") != NULL) {
+                               RTE_LOG(DEBUG, EAL, "Running on a PowerNV platform\n");
+                               powernv = true;
+                       } else if (strstr(line, "pSeries") != NULL) {
+                               RTE_LOG(DEBUG, EAL, "Running on a pSeries platform\n");
+                               pseries = true;
+                       }
+               } else if (strstr(line, "model") != NULL) {
+                       if (strstr(line, "qemu") != NULL) {
+                               RTE_LOG(DEBUG, EAL, "Found qemu emulation\n");
+                               qemu = true;
+                       }
                }
        }
 
        free(line);
        fclose(fp);
+
+       if (powernv || (pseries && !qemu))
+               ret = true;
        return ret;
 }
 #else