libxl: add 'name' field to 'libxl_device_pci' in the IDL...

... and modify libxl_pci_bdf_assignable_add/remove/list() to make use of it.

libxl_pci_bdf_assignable_add() will store the name of the device in xenstore
if the field is specified (i.e. non-NULL) and libxl_pci_bdf_assignable_remove()
will remove devices specified only by name, looking up the BDF as necessary.

libxl_pci_bdf_assignable_list() will also populate the 'name' field if a name
was stored by libxl_pci_bdf_assignable_add().

NOTE: This patch also fixes whitespace in the declaration of 'libxl_device_pci'
      in the IDL.

Signed-off-by: Paul Durrant <pdurrant@amazon.com>
Acked-by: Wei Liu <wl@xen.org>

tools/include/libxl.h

@@ -463,6 +463,12 @@
  */
 #define LIBXL_HAVE_DEVICE_PCI_ASSIGNABLE_LIST_FREE 1
 
+/*
+ * LIBXL_HAVE_DEVICE_PCI_NAME indicates that the libxl_device_pci type
+ * has a name field.
+ */
+#define LIBXL_HAVE_DEVICE_PCI_NAME 1
+
 /*
  * libxl ABI compatibility
  *

tools/libs/light/libxl_pci.c

@@ -438,7 +438,9 @@ libxl_device_pci *libxl_device_pci_assignable_list(libxl_ctx *ctx, int *num)
     }
 
     while((de = readdir(dir))) {
-        unsigned dom, bus, dev, func;
+        unsigned int dom, bus, dev, func;
+        char *name;
+
         if (sscanf(de->d_name, PCI_BDF, &dom, &bus, &dev, &func) != 4)
             continue;
 
@@ -455,6 +457,9 @@ libxl_device_pci *libxl_device_pci_assignable_list(libxl_ctx *ctx, int *num)
         if (pci_info_xs_read(gc, new, "domid")) /* already assigned */
             continue;
 
+        name = pci_info_xs_read(gc, new, "name");
+        if (name) new->name = strdup(name);
+
         (*num)++;
     }
 
@@ -742,6 +747,7 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     libxl_ctx *ctx = libxl__gc_owner(gc);
     unsigned dom, bus, dev, func;
     char *spath, *driver_path = NULL;
+    const char *name;
     int rc;
     struct stat st;
 
@@ -750,6 +756,24 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     bus = pci->bus;
     dev = pci->dev;
     func = pci->func;
+    name = pci->name;
+
+    /* Sanitise any name that is set */
+    if (name) {
+        unsigned int i, n = strlen(name);
+
+        if (n > 64) { /* Reasonable upper bound on name length */
+            LOG(ERROR, "Name too long");
+            return ERROR_FAIL;
+        }
+
+        for (i = 0; i < n; i++) {
+            if (!isgraph(name[i])) {
+                LOG(ERROR, "Names may only include printable characters");
+                return ERROR_FAIL;
+            }
+        }
+    }
 
     /* See if the device exists */
     spath = GCSPRINTF(SYSFS_PCI_DEV"/"PCI_BDF, dom, bus, dev, func);
@@ -765,7 +789,7 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
     }
     if ( rc ) {
         LOG(WARN, PCI_BDF" already assigned to pciback", dom, bus, dev, func);
-        goto quarantine;
+        goto name;
     }
 
     /* Check to see if there's already a driver that we need to unbind from */
@@ -796,7 +820,12 @@ static int libxl__device_pci_assignable_add(libxl__gc *gc,
         return ERROR_FAIL;
     }
 
-quarantine:
+name:
+    if (name)
+        pci_info_xs_write(gc, pci, "name", name);
+    else
+        pci_info_xs_remove(gc, pci, "name");
+
     /*
      * DOMID_IO is just a sentinel domain, without any actual mappings,
      * so always pass XEN_DOMCTL_DEV_RDM_RELAXED to avoid assignment being
@@ -812,6 +841,40 @@ quarantine:
     return 0;
 }
 
+static int name2bdf(libxl__gc *gc, libxl_device_pci *pci)
+{
+    char **bdfs;
+    unsigned int i, n;
+    int rc = ERROR_NOTFOUND;
+
+    bdfs = libxl__xs_directory(gc, XBT_NULL, PCI_INFO_PATH, &n);
+    if (!n)
+        goto out;
+
+    for (i = 0; i < n; i++) {
+        unsigned dom, bus, dev, func;
+        char *name;
+
+        if (sscanf(bdfs[i], PCI_BDF_XSPATH, &dom, &bus, &dev, &func) != 4)
+            continue;
+
+        pci_struct_fill(pci, dom, bus, dev, func);
+
+        name = pci_info_xs_read(gc, pci, "name");
+        if (name && !strcmp(name, pci->name)) {
+            rc = 0;
+            break;
+        }
+    }
+
+out:
+    if (!rc)
+        LOG(DETAIL, "'%s' -> " PCI_BDF, pci->name, pci->domain,
+            pci->bus, pci->dev, pci->func);
+
+    return rc;
+}
+
 static int libxl__device_pci_assignable_remove(libxl__gc *gc,
                                                libxl_device_pci *pci,
                                                int rebind)
@@ -820,6 +883,12 @@ static int libxl__device_pci_assignable_remove(libxl__gc *gc,
     int rc;
     char *driver_path;
 
+    /* If the device is named then we need to look up the BDF */
+    if (pci->name) {
+        rc = name2bdf(gc, pci);
+        if (rc) return rc;
+    }
+
     /* De-quarantine */
     rc = xc_deassign_device(ctx->xch, DOMID_IO, pci_encode_bdf(pci));
     if ( rc < 0 ) {
@@ -860,6 +929,8 @@ static int libxl__device_pci_assignable_remove(libxl__gc *gc,
         }
     }
 
+    pci_info_xs_remove(gc, pci, "name");
+
     return 0;
 }
 

tools/libs/light/libxl_types.idl

@@ -771,17 +771,18 @@ libxl_device_nic = Struct("device_nic", [
     ])
 
 libxl_device_pci = Struct("device_pci", [
-    ("func",      uint8),
-    ("dev",       uint8),
-    ("bus",       uint8),
-    ("domain",    integer),
-    ("vdevfn",    uint32),
+    ("func", uint8),
+    ("dev", uint8),
+    ("bus", uint8),
+    ("domain", integer),
+    ("vdevfn", uint32),
     ("vfunc_mask", uint32),
     ("msitranslate", bool),
     ("power_mgmt", bool),
     ("permissive", bool),
     ("seize", bool),
-    ("rdm_policy",      libxl_rdm_reserve_policy),
+    ("rdm_policy", libxl_rdm_reserve_policy),
+    ("name", string),
     ])
 
 libxl_device_rdm = Struct("device_rdm", [