Nested HVM: Provide ts-nested-setup to help make L1 usable as a host

* Provide the L1 with some storage for its own guests' disks
* Install some packages in the L1
* Optionally, set a runvar defining the L1 for the rest of the job

The recipe is going to run ts-xen-install etc.

Signed-off-by: longtao.pang <longtaox.pang@intel.com>
Signed-off-by: Robert Ho <robert.hu@intel.com>
Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Tested-by: Robert Ho <robert.hu@intel.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
---
v14: Use target_check_ip (renamed, earlier, in a new patch)
     ts-nested-setup now has a default gueststorage_size of 20G
      and this is implicitly used by make-flight.
     Adjusted for new selecthost nested host syntax and correspondingly
      completely changed invocation syntax.
     Only optionally sets the runvar, if you pass --define.  (This
      will make it easier to play around with interactively.)
     Broken the pieces of work out into subroutines for clarity.
     Comment about guest storage slightly edited and rewrapped.
     Guest storage runvars and perl variable names etc. renamed to
      `gueststorage' rather than `guest_storage'.
     LVM and VG names and perl variable names changed to be clearer.
     Install `ed' too.
     Use lv_create and toolstack()->block_attach.
     Dropped ack from Ian Campbell.

diff --git a/ts-nested-setup b/ts-nested-setup
new file mode 100755 (executable)
index 0000000..f7e0ebd
--- /dev/null
+++ b/ts-nested-setup
@@ -0,0 +1,99 @@
+#!/usr/bin/perl -w
+# This is part of "osstest", an automated testing framework for Xen.
+# Copyright (C) 2015 Intel Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+use strict qw(vars);
+use DBI;
+use Osstest;
+use Osstest::Debian;
+use Osstest::TestSupport;
+
+tsreadconfig();
+
+our $dodefine;
+if (@ARGV && $ARGV[0] eq '--define') { $dodefine=1; shift @ARGV; }
+
+our ($l1_identspec) = @ARGV;
+
+my $l1 = selecthost($l1_identspec);
+my $l0 = $l1->{Host};
+
+die unless $l0;
+
+our $def_gueststorage_size = 20000; # Mby
+
+sub packages () {
+    # Faster to install packages while L1 is still running PVHVM
+    target_install_packages_norec($l1, qw(lvm2 rsync ed genisoimage));
+}
+
+sub guest_storage () {
+    # We need to attach an extra disk to the L1 guest to be used as L2
+    # guest storage:
+    #
+    # When running in a nested HVM environment the L1 domain is acting
+    # as both a guest to L0 and a host to L2 guests and therefore
+    # potentially sees connections to two independent xenstore
+    # instances, one provided by the L0 host and one which is provided
+    # by the L1 instance of xenstore.
+    #
+    # Unfortunately the kernel is not capable of dealing with this and
+    # is only able to cope with a single xenstore connection. Since
+    # the L1 toolstack and L2 guests absolutely require xenstore to
+    # function we therefore cannot use the L0 xenstore and therefore
+    # cannot use PV devices (xvdX etc) in the L1 guest and must use
+    # emulated devices (sdX etc).
+    #
+    # However at the moment we have not yet rebooted L1 into Xen and
+    # so it does have PV devices available and sdb actually appears as
+    # xvdb.  We could disable the Xen platform device and use emulated
+    # devices for the install phase too but that would be needlessly
+    # slow.
+    # 
+    # Instead, to avoid needing to even mention the name of xvdb or
+    # sdb, we create the vg in l0.  When the l1 reboots it will
+    # automatically find the empty vg we have created for it, and
+    # target_choose_vg on l1 (which is used by all the guest creation
+    # ts-* scripts) will use it since it has plenty of space.
+
+    my $size = guest_var($l1,'gueststorage_size',$def_gueststorage_size);
+    die "gueststorage_size is undefined" unless $size;
+
+    my $outer_vg = target_choose_vg($l0, $size);
+    my $outer_lv = "$l1->{Ident}_gueststorage_outer_lv";
+    my $inner_vg = "$l1->{Ident}_gueststorage_vg";
+
+    target_cmd_root($l0, "vgremove -f $inner_vg ||:");
+    my $outer_lvdev = lv_create($l0, $outer_vg, $outer_lv, $size);
+
+    target_cmd_root($l0, <<END);
+        pvcreate $outer_lvdev
+       vgcreate $inner_vg $outer_lvdev
+END
+
+    toolstack($l0)->block_attach($l1, "$outer_lvdev,raw,sdb,rw");
+    # NB this does not update the l1 guest config so if the l1 is shut
+    # down and recreated in the l0, this will vanish.
+}
+
+packages();
+guest_storage();
+host_install_postboot_complete($l1);
+
+if ($dodefine) {
+    $l1_identspec =~ m/^(.*)=/ or die "$l1_identspec ?";
+    store_runvar($1, $'); #';
+}