[libvirt] [PATCH 3/3] scsi-disk: Deprecate device_id fallback to BlockBackend name

We should never have exposed BlockBackend names to the guest, it's a host detail. Deprecate this behaviour. Users who need to maintain the guest ABI can explicitly set the value with the device_id property. Signed-off-by: Kevin Wolf <kwolf(a)redhat.com&gt; --- hw/scsi/scsi-disk.c | 5 +++++ qemu-deprecated.texi | 22 +++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index e74e1e7c48..38f1fe2570 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -2366,6 +2366,11 @@ static void scsi_realize(SCSIDevice *dev, Error **errp) const char *str = blk_name(s->qdev.conf.blk); if (str && *str) { s->device_id = g_strdup(str); + warn_report("Using the backend drive ID for the Device " + "Identification VPD page is deprecated. " + "Please specify the serial or device_id options " + "explicitly to avoid guest-visible changes in " + "future QEMU versions."); } } } diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi index 219206a836..a426d8245d 100644 --- a/qemu-deprecated.texi +++ b/qemu-deprecated.texi @@ -146,7 +146,7 @@ This machine type uses an unmaintained firmware, broken in lots of ways, and unable to start post-2004 operating systems. 40p machine type should be used instead. -@section Device options +@section Devices @subsection Block device options @@ -170,6 +170,26 @@ The above, converted to the current supported format: @code{json:@{"file.driver":"rbd", "file.pool":"rbd", "file.image":"name"@}} +@subsection scsi-disk device identification (since 4.0.0) + +The Device Identification VPD page of ``scsi-disk'' devices contains a vendor +specific designator that can be explicitly specified using the ``device_id'' +property since 4.0.0. + +If ``device_id'' is not given, the implementation falls back to reusing any +specified serial number for this field. If the serial number is not given +either and ``drive=X'' was used where ``X'' is a drive ID, this drive ID is +given to the guest instead. This is backend information that should not +to be exposed to guests. + +Therefore, this behaviour is deprecated and future versions will change the +guest-visible behaviour (e.g. by leaving out the vendor specific designator) +for the case that neither ``device_id'' nor a serial number are given, but a +drive ID is used to create the device. + +If you need the guest-visible information to stay unchanged, add an explicit +``device_id'' option to your QEMU invocation. + @subsection vio-spapr-device device options @subsubsection "irq": "" (since 3.0.0) -- 2.20.1