Re: [libvirt] [RFC PATCH] Use disable-modern=on for disk device='lun'

https://bugzilla.redhat.com/show_bug.cgi?id=1365823 For virtio-blk, scsi=on has been deprecated in virtio-1, so <disk type='block' device='lun'> no longer works with with a virtio-blk-pci device with machine types newer than 2.7: https://bugzilla.redhat.com/show_bug.cgi?id=1245453 http://git.qemu.org/?p=qemu.git;a=commitdiff;h=9a4c0e22 Add disable-modern=on on the QEMU command line to prolong the suffering for a while longer. --- The alternative would be using the QEMU_CAPS_VIRTIO_PCI_DISABLE_LEGACY capability to report an error, instead of waiting until QEMU fails with an error, since it's the first commit when the following error should be reachable via libvirt-generated command line: http://git.qemu.org/?p=qemu.git;a=commitdiff;h=efb8206c

src/qemu/qemu_command.c | 12 +++++ .../qemuxml2argv-virtio-lun-legacy.args | 30 +++++++++++++ .../qemuxml2argv-virtio-lun-legacy.xml | 52 ++++++++++++++++++++++ tests/qemuxml2argvtest.c | 3 ++ 4 files changed, 97 insertions(+) create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-virtio-lun-legacy.args create mode 100644 tests/qemuxml2argvdata/qemuxml2argv-virtio-lun-legacy.xml diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c index 051a0bc..03dc20e 100644 --- a/src/qemu/qemu_command.c +++ b/src/qemu/qemu_command.c @@ -2075,6 +2075,18 @@ qemuBuildDriveDevStr(const virDomainDef *def, virBufferAddLit(&opt, "virtio-blk-pci"); if (disk->iothread) virBufferAsprintf(&opt, ",iothread=iothread%u", disk->iothread); + + /* + * SCSI command passthrough was deprecated in virtio 1.0, + * see https://bugzilla.redhat.com/show_bug.cgi?id=1365823 + */ + if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_BLK_SCSI) && + disk->device == VIR_DOMAIN_DISK_DEVICE_LUN && + virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_PCI_DISABLE_LEGACY)) { + VIR_WARN("lun type devices are deprecated for virtio-blk-pci devices, " + "consider using disks on a virtio-scsi controller");

+ virBufferAddLit(&opt, ",disable-modern=on"); + } }