[libvirt] [PATCH 2/4 v2] pci: Add helper functions for sriov devices

[Roopa Prabhu]

From: Roopa Prabhu <roprabhu at cisco.com>

This patch adds the following helper functions:
pciDeviceIsVirtualFunction: Function to check if a pci device is a sriov VF
pciGetVirtualFunctionIndex: Function to get the VF index of a sriov VF
pciDeviceNetName: Function to get the network device name of a pci device
pciConfigAddressCompare: Function to compare pci config addresses

Signed-off-by: Roopa Prabhu <roprabhu at cisco.com>
Signed-off-by: Christian Benvenuti <benve at cisco.com>
Signed-off-by: David Wang <dwang2 at cisco.com>
---
 src/util/pci.c |  118 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/pci.h |   15 +++++++
 2 files changed, 133 insertions(+), 0 deletions(-)


diff --git a/src/util/pci.c b/src/util/pci.c
index e017db9..558c7ae 100644
--- a/src/util/pci.c
+++ b/src/util/pci.c
@@ -1875,3 +1875,121 @@ out:
 
     return ret;
 }
+
+/*
+ * returns 0 if equal and 1 if not
+ */
+static int
+pciConfigAddressCompare(struct pci_config_address *bdf1,
+                        struct pci_config_address *bdf2)
+{
+    return !((bdf1->domain == bdf2->domain) &
+             (bdf1->bus == bdf2->bus) &
+             (bdf1->slot == bdf2->slot) &
+             (bdf1->function == bdf2->function));
+}
+
+/*
+ * Returns 1 if vf device is a virtual function, 0 if not, -1 on error
+ */
+int
+pciDeviceIsVirtualFunctionLinux(const char *vf_sysfs_device_link)
+{
+    char *vf_sysfs_physfn_link = NULL;
+    int ret = -1;
+
+    if (virAsprintf(&vf_sysfs_physfn_link, "%s/physfn",
+        vf_sysfs_device_link) < 0) {
+        virReportOOMError();
+        return ret;
+    }
+
+    ret = virFileExists(vf_sysfs_physfn_link);
+
+    VIR_FREE(vf_sysfs_physfn_link);
+
+    return ret;
+}
+
+/*
+ * Returns the sriov virtual function index of vf given its pf
+ */
+int
+pciGetVirtualFunctionIndexLinux(const char *pf_sysfs_device_link,
+                                const char *vf_sysfs_device_link,
+                                int *vf_index)
+{
+    int ret = -1, i;
+    unsigned int num_virt_fns = 0;
+    struct pci_config_address *vf_bdf = NULL;
+    struct pci_config_address **virt_fns = NULL;
+
+    if (pciGetPciConfigAddressFromSysfsDeviceLink(vf_sysfs_device_link,
+        &vf_bdf))
+        return ret;
+
+    if (pciGetVirtualFunctionsLinux(pf_sysfs_device_link, &virt_fns,
+        &num_virt_fns)) {
+        VIR_DEBUG("Error getting physical function's '%s' virtual_functions\n",
+                  pf_sysfs_device_link);
+        goto out;
+    }
+
+    for (i = 0; i < num_virt_fns; i++) {
+         if (!pciConfigAddressCompare(vf_bdf, virt_fns[i])) {
+             *vf_index = i;
+             ret = 0;
+             break;
+         }
+    }
+
+out:
+
+    /* free virtual functions */
+    for (i = 0; i < num_virt_fns; i++)
+         VIR_FREE(virt_fns[i]);
+
+    VIR_FREE(vf_bdf);
+
+    return ret;
+}
+
+/*
+ * Returns the network device name of a pci device
+ */
+int
+pciDeviceNetNameLinux(char *device_link_sysfs_path, char **netname)
+{
+     char *pcidev_sysfs_net_path = NULL;
+     int ret = -1;
+     DIR *dir = NULL;
+     struct dirent *entry = NULL;
+
+     if (virBuildPath(&pcidev_sysfs_net_path, device_link_sysfs_path,
+         "net") == -1) {
+         virReportOOMError();
+         return -1;
+     }
+
+     dir = opendir(pcidev_sysfs_net_path);
+     if (dir == NULL)
+         goto out;
+
+     while ((entry = readdir(dir))) {
+            if (!strcmp(entry->d_name, ".") ||
+                !strcmp(entry->d_name, ".."))
+                continue;
+
+            /* Assume a single directory entry */
+            *netname = strdup(entry->d_name);
+            ret = 0;
+            break;
+     }
+
+     closedir(dir);
+
+out:
+     VIR_FREE(pcidev_sysfs_net_path);
+
+     return ret;
+}
diff --git a/src/util/pci.h b/src/util/pci.h
index 367881e..0cdc6ec 100644
--- a/src/util/pci.h
+++ b/src/util/pci.h
@@ -92,10 +92,25 @@ int pciGetVirtualFunctionsLinux(const char *sysfs_path,
                                 struct pci_config_address ***virtual_functions,
                                 unsigned int *num_virtual_functions);
 
+# define pciDeviceIsVirtualFunction(v) pciDeviceIsVirtualFunctionLinux(v)
+int pciDeviceIsVirtualFunctionLinux(const char *vf_sysfs_device_link);
+
+# define pciGetVirtualFunctionIndex(p,v,i) \
+         pciGetVirtualFunctionIndexLinux(p,v,i)
+int pciGetVirtualFunctionIndexLinux(const char *pf_sysfs_device_link,
+                                    const char *vf_sysfs_device_link,
+                                    int *vf_index);
+
+# define pciDeviceNetName(d,n) pciDeviceNetNameLinux(d,n)
+int pciDeviceNetNameLinux(char *device_link_sysfs_path, char **netname);
+
 #else /* __linux__ */
 
 #  define pciGetPhysicalFunction(s,a)
 #  define pciGetVirtualFunctions(s,a,n)
+#  define pciDeviceIsVirtualFunction(v)
+#  define pciGetVirtualFunctionIndex(p,v,i)
+#  define pciDeviceNetNameLinux(d,n)
 
 #endif