[libvirt] [PATCH 3/4] xen: fix PyGrub boot device order
When PyGrub is used as the bootloader in Xen, it gets passed the first
bootable disk. Xend supports a "bootable"-flag for this, which isn't
explicitly supported by libvirt.
When converting libvirt-xml to xen-sxpr the "bootable"-flag gets
implicitly set by xen.xend.XenConfig.device_add() for the first disk
(marked as "Compat hack -- mark first disk bootable").
When converting back xen-sxpr to libvirt-xml, the disks are returned in
the internal order used by Xend ignoring the "bootable"-flag, which
looses the original order. When the domain is then re-defined, the order
of disks is changed, which breaks PyGrub, since a different disk gets
passed.
When converting xen-sxpt to libvirt-xml, use the "bootable"-flag to
determine the first disk.
This isn't perfect, since several disks can be marked as bootable using
the Xend-API, but that is not supported by libvirt. In all known cases
relevant to libvirt exactly one disk is marked as bootable.
Signed-off-by: Philipp Hahn <hahn(a)univention.de>
---
valgrind might complain about an uninitialized read access when copying
disks[0] to disks[0], but that is overwritten again with the following
assignment.
<https://forge.univention.org/bugzilla/show_bug.cgi?id=21938>
src/xenxs/xen_sxpr.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)
diff --git a/src/xenxs/xen_sxpr.c b/src/xenxs/xen_sxpr.c
index 72322a7..038c6bb 100644
--- a/src/xenxs/xen_sxpr.c
+++ b/src/xenxs/xen_sxpr.c
@@ -342,20 +342,24 @@ xenParseSxprDisks(virDomainDefPtr def,
const char *src = NULL;
const char *dst = NULL;
const char *mode = NULL;
+ const char *bootable = NULL;
/* Again dealing with (vbd...) vs (tap ...) differences */
if (sexpr_lookup(node, "device/vbd")) {
src = sexpr_node(node, "device/vbd/uname");
dst = sexpr_node(node, "device/vbd/dev");
mode = sexpr_node(node, "device/vbd/mode");
+ bootable = sexpr_node(node, "device/vbd/bootable");
} else if (sexpr_lookup(node, "device/tap2")) {
src = sexpr_node(node, "device/tap2/uname");
dst = sexpr_node(node, "device/tap2/dev");
mode = sexpr_node(node, "device/tap2/mode");
+ bootable = sexpr_node(node, "device/tap2/bootable");
} else {
src = sexpr_node(node, "device/tap/uname");
dst = sexpr_node(node, "device/tap/dev");
mode = sexpr_node(node, "device/tap/mode");
+ bootable = sexpr_node(node, "device/tap/bootable");
}
if (VIR_ALLOC(disk) < 0)
@@ -481,7 +485,13 @@ xenParseSxprDisks(virDomainDefPtr def,
if (VIR_REALLOC_N(def->disks, def->ndisks+1) < 0)
goto no_memory;
- def->disks[def->ndisks++] = disk;
+ /* re-order disks if there is a bootable device */
+ if (STREQ_NULLABLE(bootable, "1")) {
+ def->disks[def->ndisks++] = def->disks[0];
+ def->disks[0] = disk;
+ } else {
+ def->disks[def->ndisks++] = disk;
+ }
disk = NULL;
}
}
--
1.7.1