From: Stefano Stabellini Date: Tue, 22 Sep 2015 15:56:35 +0000 (+0100) Subject: libxl: handle read-only drives with qemu-xen X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=e4f09370f24a2226125659973655b9bae384f903;p=xen.git libxl: handle read-only drives with qemu-xen The current libxl code doesn't deal with read-only drives at all. Upstream QEMU and qemu-xen only support read-only cdrom drives: make sure to specify "readonly=on" for cdrom drives and return error in case the user requested a non-cdrom read-only drive. This is XSA-142, discovered by Lin Liu (https://bugzilla.redhat.com/show_bug.cgi?id=1257893). Signed-off-by: Stefano Stabellini Backport to Xen 4.5 and earlier, apropos of report and review from Michael Young. Signed-off-by: Ian Jackson (cherry picked from commit 998424e33db121270690586320e899a03c88b4aa) (Backport to 4.2 and earlier.) Conflicts: tools/libxl/libxl_dm.c Signed-off-by: Ian Jackson --- diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c index 6a1b91fd2b..ea2ba01299 100644 --- a/tools/libxl/libxl_dm.c +++ b/tools/libxl/libxl_dm.c @@ -574,12 +574,18 @@ static char ** libxl__build_device_model_args_new(libxl__gc *gc, if (disks[i].is_cdrom) { if (disks[i].format == LIBXL_DISK_FORMAT_EMPTY) drive = libxl__sprintf - (gc, "if=ide,index=%d,media=cdrom,cache=writeback", disk); + (gc, "if=ide,index=%d,readonly=%s,media=cdrom,cache=writeback", + disk, disks[i].readwrite ? "off" : "on"); else drive = libxl__sprintf - (gc, "file=%s,if=ide,index=%d,media=cdrom,format=%s,cache=writeback", - disks[i].pdev_path, disk, format); + (gc, "file=%s,if=ide,index=%d,readonly=%s,media=cdrom,format=%s,cache=writeback", + disks[i].pdev_path, disk, disks[i].readwrite ? "off" : "on", format); } else { + if (!disks[i].readwrite) { + LIBXL__LOG(ctx, LIBXL__LOG_ERROR, "qemu-xen doesn't support read-only disk drivers"); + return NULL; + } + if (disks[i].format == LIBXL_DISK_FORMAT_EMPTY) { LIBXL__LOG(ctx, LIBXL__LOG_WARNING, "cannot support" " empty disk format for %s", disks[i].vdev);