[PATCH v2] tools/helpers/init-dom0less: fix vcpu availability

[Amneesh Singh <a-singh21@xxxxxx>]

Currently, writing at cpu/<cpu>/availability in xenstore fails for a
couple of reasons: a trailing slash in the path and the fact that
cpupool isn't a bitmap but the cpupool id. This patch fixes this by
just getting libxl_vcpuinfo for each dom0less domain.

Signed-off-by: Amneesh Singh <a-singh21@xxxxxx>
---
 tools/helpers/init-dom0less.c | 46 ++++++++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 14 deletions(-)
---
v1 -> v2:
- check for libxl_list_vcpu failure
- skip writing cpu availability to store if the above failure occurs

diff --git a/tools/helpers/init-dom0less.c b/tools/helpers/init-dom0less.c
index fee9345..722a5af 100644
--- a/tools/helpers/init-dom0less.c
+++ b/tools/helpers/init-dom0less.c
@@ -99,8 +99,8 @@ static bool do_xs_write_vm(struct xs_handle *xsh, 
xs_transaction_t t,
  * domain started by xl/libxl.
  */
 static int create_xenstore(struct xs_handle *xsh,
-                           libxl_dominfo *info, libxl_uuid uuid,
-                           evtchn_port_t xenstore_port)
+                           libxl_dominfo *info, libxl_vcpuinfo *vcpuinfo,
+                           libxl_uuid uuid, evtchn_port_t xenstore_port)
 {
     domid_t domid;
     unsigned int i;
@@ -167,15 +167,20 @@ retry_transaction:
     /* /domain */
     if (!do_xs_write_dom(xsh, t, domid, "vm", vm_val_str)) goto err;
     if (!do_xs_write_dom(xsh, t, domid, "name", dom_name_str)) goto err;
-    if (!do_xs_write_dom(xsh, t, domid, "cpu", "")) goto err;
-    for (i = 0; i < info->vcpu_max_id; i++) {
-        rc = snprintf(cpu_str, STR_MAX_LENGTH, "cpu/%u/availability/", i);
-        if (rc < 0 || rc >= STR_MAX_LENGTH)
-            goto err;
-        rc = -EIO;
-        if (!do_xs_write_dom(xsh, t, domid, cpu_str,
-                             (info->cpupool & (1 << i)) ? "online" : 
"offline"))
-            goto err;
+
+    if (!vcpuinfo) {
+        fprintf(stderr, "vcpu information unavailable, proceeding without 
it\n");
+    } else {
+        if (!do_xs_write_dom(xsh, t, domid, "cpu", "")) goto err;
+        for (i = 0; i <= info->vcpu_max_id; i++) {
+            rc = snprintf(cpu_str, STR_MAX_LENGTH, "cpu/%u/availability", i);
+            if (rc < 0 || rc >= STR_MAX_LENGTH)
+                goto err;
+            rc = -EIO;
+            if (!do_xs_write_dom(xsh, t, domid, cpu_str,
+                                vcpuinfo[i].online ? "online" : "offline"))
+                goto err;
+        }
     }
 
     if (!do_xs_write_dom(xsh, t, domid, "memory", "")) goto err;
@@ -225,7 +230,8 @@ err:
 static int init_domain(struct xs_handle *xsh,
                        struct xc_interface_core *xch,
                        xenforeignmemory_handle *xfh,
-                       libxl_dominfo *info)
+                       libxl_dominfo *info,
+                       libxl_vcpuinfo *vcpuinfo)
 {
     libxl_uuid uuid;
     uint64_t xenstore_evtchn, xenstore_pfn;
@@ -278,7 +284,7 @@ static int init_domain(struct xs_handle *xsh,
     if (rc < 0)
         return rc;
 
-    rc = create_xenstore(xsh, info, uuid, xenstore_evtchn);
+    rc = create_xenstore(xsh, info, vcpuinfo, uuid, xenstore_evtchn);
     if (rc)
         err(1, "writing to xenstore");
 
@@ -330,14 +336,24 @@ int main(int argc, char **argv)
 
     for (i = 0; i < nb_vm; i++) {
         domid_t domid = info[i].domid;
+        libxl_vcpuinfo *vcpuinfo;
+        int nb_vcpu = 0, nr_cpus = 0;
+
 
         /* Don't need to check for Dom0 */
         if (!domid)
             continue;
 
+        vcpuinfo = libxl_list_vcpu(ctx, domid, &nb_vcpu, &nr_cpus);
+
+        if (!vcpuinfo) {
+          fprintf(stderr, "libxl_list_vcpu failed.\n");
+          nb_vcpu = 0;
+        }
+
         printf("Checking domid: %u\n", domid);
         if (!domain_exists(xsh, domid)) {
-            rc = init_domain(xsh, xch, xfh, &info[i]);
+            rc = init_domain(xsh, xch, xfh, &info[i], vcpuinfo);
             if (rc < 0) {
                 fprintf(stderr, "init_domain failed.\n");
                 goto out;
@@ -345,6 +361,8 @@ int main(int argc, char **argv)
         } else {
             printf("Domain %u has already been initialized\n", domid);
         }
+
+        libxl_vcpuinfo_list_free(vcpuinfo, nb_vcpu);
     }
 out:
     libxl_dominfo_list_free(info, nb_vm);
-- 
2.34.1