qemu: process: Don't clear QEMU_CAPS_BLOCKDEV when SD card is present

Help QEMU in deprecation of -drive if=none without the need to refactor
all old boards. Stop masking out -blockdev support when -drive if=sd
needs to be used. We achieve this by forbidding blockjobs and
special-casing all other code paths. Blockjobs are sacrificed in this
case as SD cards are a corner case for some ARM boards and are thus not
used commonly.

https://bugzilla.redhat.com/show_bug.cgi?id=1821692Signed-off-by: NPeter Krempa <pkrempa@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_process.c

@@ -5488,7 +5488,6 @@ qemuProcessPrepareQEMUCaps(virDomainObjPtr vm,
                            unsigned int processStartFlags)
 {
     qemuDomainObjPrivatePtr priv = vm->privateData;
-    size_t i;
 
     virObjectUnref(priv->qemuCaps);
     if (!(priv->qemuCaps = virQEMUCapsCacheLookupCopy(qemuCapsCache,
@@ -5497,14 +5496,6 @@ qemuProcessPrepareQEMUCaps(virDomainObjPtr vm,
                                                       vm->def->os.machine)))
         return -1;
 
-    /* clear the 'blockdev' capability for VMs which have disks that need -drive */
-    for (i = 0; i < vm->def->ndisks; i++) {
-        if (qemuDiskBusIsSD(vm->def->disks[i]->bus)) {
-            virQEMUCapsClear(priv->qemuCaps, QEMU_CAPS_BLOCKDEV);
-            break;
-        }
-    }
-
     if (processStartFlags & VIR_QEMU_PROCESS_START_STANDALONE)
         virQEMUCapsClear(priv->qemuCaps, QEMU_CAPS_CHARDEV_FD_PASS);
 

tests/qemuxml2argvdata/disk-arm-virtio-sd.aarch64-latest.args

@@ -33,8 +33,11 @@ file=/tmp/lib/domain--1-armtest/master-key.aes \
 -dtb /arm.dtb \
 -usb \
 -drive file=/arm-sd.qcow2,format=qcow2,if=sd,index=0 \
--drive file=/arm-virtio.qcow2,format=qcow2,if=none,id=drive-virtio-disk0 \
--device virtio-blk-device,scsi=off,drive=drive-virtio-disk0,id=virtio-disk0 \
+-blockdev '{"driver":"file","filename":"/arm-virtio.qcow2",\
+"node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}' \
+-blockdev '{"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2",\
+"file":"libvirt-1-storage"}' \
+-device virtio-blk-device,scsi=off,drive=libvirt-1-format,id=virtio-disk0 \
 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,\
 resourcecontrol=deny \
 -msg timestamp=on