[xen master] libxl: Make sure devices added by pci-attach are reflected in the config

[patchbot@xxxxxxx]

commit 0fdb48ffe7a1a56745b999506bf572e260e8ae0a
Author:     Paul Durrant <pdurrant@xxxxxxxxxx>
AuthorDate: Tue Dec 8 19:30:12 2020 +0000
Commit:     Wei Liu <wl@xxxxxxx>
CommitDate: Tue Dec 15 16:24:23 2020 +0000

    libxl: Make sure devices added by pci-attach are reflected in the config
    
    Currently libxl__device_pci_add_xenstore() is broken in that does not
    update the domain's configuration for the first device added (which causes
    creation of the overall backend area in xenstore). This can be easily 
observed
    by running 'xl list -l' after adding a single device: the device will be
    missing.
    
    This patch fixes the problem and adds a DEBUG log line to allow easy
    verification that the domain configuration is being modified. Also, the use
    of libxl__device_generic_add() is dropped as it leads to a confusing 
situation
    where only partial backend information is written under the xenstore
    '/libxl' path. For LIBXL__DEVICE_KIND_PCI devices the only definitive
    information in xenstore is under '/local/domain/0/backend' (the '0' being
    hard-coded).
    
    NOTE: This patch includes a whitespace in add_pcis_done().
    
    Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
    Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
    Acked-by: Wei Liu <wl@xxxxxxx>
---
 tools/libs/light/libxl_pci.c | 87 +++++++++++++++++++++++---------------------
 1 file changed, 45 insertions(+), 42 deletions(-)

diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
index d536702ac4..3f85f0d762 100644
--- a/tools/libs/light/libxl_pci.c
+++ b/tools/libs/light/libxl_pci.c
@@ -79,39 +79,55 @@ static void libxl__device_from_pci(libxl__gc *gc, uint32_t 
domid,
     device->kind = LIBXL__DEVICE_KIND_PCI;
 }
 
-static int libxl__create_pci_backend(libxl__gc *gc, uint32_t domid,
-                                     const libxl_device_pci *pci,
-                                     int num)
+static void libxl__create_pci_backend(libxl__gc *gc, xs_transaction_t t,
+                                      uint32_t domid, const libxl_device_pci 
*pci)
 {
-    flexarray_t *front = NULL;
-    flexarray_t *back = NULL;
-    libxl__device device;
-    int i;
+    libxl_ctx *ctx = libxl__gc_owner(gc);
+    flexarray_t *front, *back;
+    char *fe_path, *be_path;
+    struct xs_permissions fe_perms[2], be_perms[2];
+
+    LOGD(DEBUG, domid, "Creating pci backend");
 
     front = flexarray_make(gc, 16, 1);
     back = flexarray_make(gc, 16, 1);
 
-    LOGD(DEBUG, domid, "Creating pci backend");
-
-    /* add pci device */
-    libxl__device_from_pci(gc, domid, pci, &device);
+    fe_path = libxl__domain_device_frontend_path(gc, domid, 0,
+                                                 LIBXL__DEVICE_KIND_PCI);
+    be_path = libxl__domain_device_backend_path(gc, 0, domid, 0,
+                                                LIBXL__DEVICE_KIND_PCI);
 
+    flexarray_append_pair(back, "frontend", fe_path);
     flexarray_append_pair(back, "frontend-id", GCSPRINTF("%d", domid));
-    flexarray_append_pair(back, "online", "1");
+    flexarray_append_pair(back, "online", GCSPRINTF("%d", 1));
     flexarray_append_pair(back, "state", GCSPRINTF("%d", 
XenbusStateInitialising));
     flexarray_append_pair(back, "domain", libxl__domid_to_name(gc, domid));
 
-    for (i = 0; i < num; i++, pci++)
-        libxl_create_pci_backend_device(gc, back, i, pci);
+    be_perms[0].id = 0;
+    be_perms[0].perms = XS_PERM_NONE;
+    be_perms[1].id = domid;
+    be_perms[1].perms = XS_PERM_READ;
+
+    xs_rm(ctx->xsh, t, be_path);
+    xs_mkdir(ctx->xsh, t, be_path);
+    xs_set_permissions(ctx->xsh, t, be_path, be_perms,
+                       ARRAY_SIZE(be_perms));
+    libxl__xs_writev(gc, t, be_path, libxl__xs_kvs_of_flexarray(gc, back));
 
-    flexarray_append_pair(back, "num_devs", GCSPRINTF("%d", num));
+    flexarray_append_pair(front, "backend", be_path);
     flexarray_append_pair(front, "backend-id", GCSPRINTF("%d", 0));
     flexarray_append_pair(front, "state", GCSPRINTF("%d", 
XenbusStateInitialising));
 
-    return libxl__device_generic_add(gc, XBT_NULL, &device,
-                                     libxl__xs_kvs_of_flexarray(gc, back),
-                                     libxl__xs_kvs_of_flexarray(gc, front),
-                                     NULL);
+    fe_perms[0].id = domid;
+    fe_perms[0].perms = XS_PERM_NONE;
+    fe_perms[1].id = 0;
+    fe_perms[1].perms = XS_PERM_READ;
+
+    xs_rm(ctx->xsh, t, fe_path);
+    xs_mkdir(ctx->xsh, t, fe_path);
+    xs_set_permissions(ctx->xsh, t, fe_path,
+                       fe_perms, ARRAY_SIZE(fe_perms));
+    libxl__xs_writev(gc, t, fe_path, libxl__xs_kvs_of_flexarray(gc, front));
 }
 
 static int libxl__device_pci_add_xenstore(libxl__gc *gc,
@@ -135,8 +151,6 @@ static int libxl__device_pci_add_xenstore(libxl__gc *gc,
     be_path = libxl__domain_device_backend_path(gc, 0, domid, 0,
                                                 LIBXL__DEVICE_KIND_PCI);
     num_devs = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("%s/num_devs", be_path));
-    if (!num_devs)
-        return libxl__create_pci_backend(gc, domid, pci, 1);
 
     libxl_domain_type domtype = libxl__domain_type(gc, domid);
     if (domtype == LIBXL_DOMAIN_TYPE_INVALID)
@@ -150,17 +164,17 @@ static int libxl__device_pci_add_xenstore(libxl__gc *gc,
     back = flexarray_make(gc, 16, 1);
 
     LOGD(DEBUG, domid, "Adding new pci device to xenstore");
-    num = atoi(num_devs);
+    num = num_devs ? atoi(num_devs) : 0;
     libxl_create_pci_backend_device(gc, back, num, pci);
     flexarray_append_pair(back, "num_devs", GCSPRINTF("%d", num + 1));
-    if (!starting)
+    if (num && !starting)
         flexarray_append_pair(back, "state", GCSPRINTF("%d", 
XenbusStateReconfiguring));
 
     /*
      * Stubdomin config is derived from its target domain, it doesn't have
      * its own file.
      */
-    if (!is_stubdomain) {
+    if (!is_stubdomain && !starting) {
         lock = libxl__lock_domain_userdata(gc, domid);
         if (!lock) {
             rc = ERROR_LOCK_FAIL;
@@ -170,6 +184,7 @@ static int libxl__device_pci_add_xenstore(libxl__gc *gc,
         rc = libxl__get_domain_configuration(gc, domid, &d_config);
         if (rc) goto out;
 
+        LOGD(DEBUG, domid, "Adding new pci device to config");
         device_add_domain_config(gc, &d_config, &libxl__pci_devtype,
                                  pci);
 
@@ -186,6 +201,10 @@ static int libxl__device_pci_add_xenstore(libxl__gc *gc,
             if (rc) goto out;
         }
 
+        /* This is the first device, so create the backend */
+        if (!num_devs)
+            libxl__create_pci_backend(gc, t, domid, pci);
+
         libxl__xs_writev(gc, t, be_path, libxl__xs_kvs_of_flexarray(gc, back));
 
         rc = libxl__xs_transaction_commit(gc, &t);
@@ -1437,7 +1456,7 @@ out_no_irq:
         }
     }
 
-    if (!starting && !libxl_get_stubdom_id(CTX, domid))
+    if (!libxl_get_stubdom_id(CTX, domid))
         rc = libxl__device_pci_add_xenstore(gc, domid, pci, starting);
     else
         rc = 0;
@@ -1765,28 +1784,12 @@ static void libxl__add_pcis(libxl__egc *egc, libxl__ao 
*ao, uint32_t domid,
 }
 
 static void add_pcis_done(libxl__egc *egc, libxl__multidev *multidev,
-                             int rc)
+                          int rc)
 {
     EGC_GC;
     add_pcis_state *apds = CONTAINER_OF(multidev, *apds, multidev);
-
-    /* Convenience aliases */
-    libxl_domain_config *d_config = apds->d_config;
-    libxl_domid domid = apds->domid;
     libxl__ao_device *aodev = apds->outer_aodev;
 
-    if (rc) goto out;
-
-    if (d_config->num_pcidevs > 0 && !libxl_get_stubdom_id(CTX, domid)) {
-        rc = libxl__create_pci_backend(gc, domid, d_config->pcidevs,
-                                       d_config->num_pcidevs);
-        if (rc < 0) {
-            LOGD(ERROR, domid, "libxl_create_pci_backend failed: %d", rc);
-            goto out;
-        }
-    }
-
-out:
     aodev->rc = rc;
     aodev->callback(egc, aodev);
 }
--
generated by git-patchbot for /home/xen/git/xen.git#master