On 5/28/26 21:36, Denis V. Lunev wrote:
> virDomainDefMaybeAddHostdevSCSIcontroller() already inherits the
> model of an existing SCSI controller when auto-adding peers driven
> by a hostdev whose drive address overflows the highest declared
> idx. virDomainDefAddDiskControllersForType(), called for the
> disk-driven analogue, does not -- it passes model=-1 unconditionally.
> The unspecified peers then arrive at qemuDomainDefaultSCSIControllerModel()
> and pick up whichever model the capability cascade settles on
> (typically lsilogic). A user-declared virtio-scsi controller at
> idx 0 ends up alongside auto-added lsilogic peers at idx 1+.
>
> Plug the same inheritance into qemuDomainDefaultSCSIControllerModel()
> itself so it covers both the disk-driven path and any other caller
> that arrives with an unresolved model. The function already prefers
> architectural defaults (PSeries, ARM virt, RISC-V virt, LoongArch,
> s390, built-in ESP) over capabilities; peer inheritance slots in
> just before the capability cascade. A virtio-scsi domain keeps the
> new peers as virtio-scsi; an lsisas1068 domain stays lsisas1068; a
> fresh domain with no SCSI controllers still gets the cap-driven
> default. controller-scsi-auto, the only existing test that flows
> through this helper, is unaffected (it has no peers to inherit
> from). controller-scsi-inherit-model covers the new behavior.
>
> Signed-off-by: Denis V. Lunev <[email protected]>
> ---
> src/qemu/qemu_domain.c | 15 +++++++
> ...ller-scsi-inherit-model.x86_64-latest.args | 38 ++++++++++++++++
> ...oller-scsi-inherit-model.x86_64-latest.xml | 45 +++++++++++++++++++
> .../controller-scsi-inherit-model.xml | 20 +++++++++
> tests/qemuxmlconftest.c | 1 +
> 5 files changed, 119 insertions(+)
> create mode 100644
> tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.args
> create mode 100644
> tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.xml
> create mode 100644 tests/qemuxmlconfdata/controller-scsi-inherit-model.xml
>
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 84c8645259..21f2641521 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -4289,6 +4289,8 @@ virDomainControllerModelSCSI
> qemuDomainDefaultSCSIControllerModel(const virDomainDef *def,
> virQEMUCaps *qemuCaps)
> {
> + size_t i;
> +
> /* For machine types with built-in SCSI controllers, the choice
> * of model is obvious */
> if (qemuDomainHasBuiltinESP(def))
> @@ -4305,6 +4307,19 @@ qemuDomainDefaultSCSIControllerModel(const
> virDomainDef *def,
> if (qemuDomainIsPSeries(def))
> return VIR_DOMAIN_CONTROLLER_MODEL_SCSI_IBMVSCSI;
>
> + /* Inherit the model from any peer SCSI controller already
> + * resolved on this domain. */
> + for (i = 0; i < def->ncontrollers; i++) {
> + const virDomainControllerDef *peer = def->controllers[i];
> +
> + if (peer->type != VIR_DOMAIN_CONTROLLER_TYPE_SCSI)
> + continue;
> + if (peer->model == VIR_DOMAIN_CONTROLLER_MODEL_SCSI_DEFAULT ||
> + peer->model == VIR_DOMAIN_CONTROLLER_MODEL_SCSI_AUTO)
> + continue;
> + return peer->model;
> + }
> +
> /* If there is no preference, base the choice on device
> * availability. In this case, lsilogic is favored over
> * virtio-scsi for backwards compatibility reasons */
> diff --git
> a/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.args
> b/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.args
> new file mode 100644
> index 0000000000..2bcd9ed92f
> --- /dev/null
> +++ b/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.args
> @@ -0,0 +1,38 @@
> +LC_ALL=C \
> +PATH=/bin \
> +HOME=/var/lib/libvirt/qemu/domain--1-guest \
> +USER=test \
> +LOGNAME=test \
> +XDG_DATA_HOME=/var/lib/libvirt/qemu/domain--1-guest/.local/share \
> +XDG_CACHE_HOME=/var/lib/libvirt/qemu/domain--1-guest/.cache \
> +XDG_CONFIG_HOME=/var/lib/libvirt/qemu/domain--1-guest/.config \
> +/usr/bin/qemu-system-x86_64 \
> +-name guest=guest,debug-threads=on \
> +-S \
> +-object
> '{"qom-type":"secret","id":"masterKey0","format":"raw","file":"/var/lib/libvirt/qemu/domain--1-guest/master-key.aes"}'
> \
> +-machine pc,usb=off,dump-guest-core=off,memory-backend=pc.ram,acpi=off \
> +-accel tcg \
> +-cpu qemu64 \
> +-m size=219136k \
> +-object '{"qom-type":"memory-backend-ram","id":"pc.ram","size":224395264}' \
> +-overcommit mem-lock=off \
> +-smp 8,sockets=8,cores=1,threads=1 \
> +-uuid c7a5fdbd-edaf-9455-926a-d65c16db1809 \
> +-display none \
> +-no-user-config \
> +-nodefaults \
> +-chardev socket,id=charmonitor,fd=@mon-fd@,server=on,wait=off \
> +-mon chardev=charmonitor,id=monitor,mode=control \
> +-rtc base=utc \
> +-no-shutdown \
> +-boot strict=on \
> +-device
> '{"driver":"virtio-scsi-pci","id":"scsi0","bus":"pci.0","addr":"0x2"}' \
> +-device
> '{"driver":"virtio-scsi-pci","id":"scsi1","bus":"pci.0","addr":"0x3"}' \
> +-device
> '{"driver":"virtio-scsi-pci","id":"scsi2","bus":"pci.0","addr":"0x4"}' \
> +-device
> '{"driver":"virtio-scsi-pci","id":"scsi3","bus":"pci.0","addr":"0x5"}' \
> +-blockdev
> '{"driver":"file","filename":"/tmp/data.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
> '{"driver":"scsi-hd","bus":"scsi3.0","channel":0,"scsi-id":0,"lun":3,"device_id":"drive-scsi3-0-0-3","drive":"libvirt-1-format","id":"scsi3-0-0-3","bootindex":1}'
> \
> +-audiodev '{"id":"audio1","driver":"none"}' \
> +-sandbox
> on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny \
> +-msg timestamp=on
> diff --git
> a/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.xml
> b/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.xml
> new file mode 100644
> index 0000000000..b971c89a1b
> --- /dev/null
> +++ b/tests/qemuxmlconfdata/controller-scsi-inherit-model.x86_64-latest.xml
> @@ -0,0 +1,45 @@
> +<domain type='qemu'>
> + <name>guest</name>
> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> + <memory unit='KiB'>219136</memory>
> + <currentMemory unit='KiB'>219136</currentMemory>
> + <vcpu placement='static'>8</vcpu>
> + <os>
> + <type arch='x86_64' machine='pc'>hvm</type>
> + <boot dev='hd'/>
> + </os>
> + <cpu mode='custom' match='exact' check='none'>
> + <model fallback='forbid'>qemu64</model>
> + </cpu>
> + <clock offset='utc'/>
> + <on_poweroff>destroy</on_poweroff>
> + <on_reboot>restart</on_reboot>
> + <on_crash>destroy</on_crash>
> + <devices>
> + <emulator>/usr/bin/qemu-system-x86_64</emulator>
> + <disk type='file' device='disk'>
> + <driver name='qemu' type='qcow2'/>
> + <source file='/tmp/data.qcow2'/>
> + <target dev='sdy' bus='scsi'/>
> + <address type='drive' controller='3' bus='0' target='0' unit='3'/>
> + </disk>
> + <controller type='scsi' index='0' model='virtio-scsi'>
> + <address type='pci' domain='0x0000' bus='0x00' slot='0x02'
> function='0x0'/>
> + </controller>
> + <controller type='scsi' index='1' model='virtio-scsi'>
> + <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
> function='0x0'/>
> + </controller>
> + <controller type='scsi' index='2' model='virtio-scsi'>
> + <address type='pci' domain='0x0000' bus='0x00' slot='0x04'
> function='0x0'/>
> + </controller>
> + <controller type='scsi' index='3' model='virtio-scsi'>
> + <address type='pci' domain='0x0000' bus='0x00' slot='0x05'
> function='0x0'/>
> + </controller>
> + <controller type='usb' index='0' model='none'/>
> + <controller type='pci' index='0' model='pci-root'/>
> + <input type='mouse' bus='ps2'/>
> + <input type='keyboard' bus='ps2'/>
> + <audio id='1' type='none'/>
> + <memballoon model='none'/>
> + </devices>
> +</domain>
> diff --git a/tests/qemuxmlconfdata/controller-scsi-inherit-model.xml
> b/tests/qemuxmlconfdata/controller-scsi-inherit-model.xml
> new file mode 100644
> index 0000000000..45e96b7ea1
> --- /dev/null
> +++ b/tests/qemuxmlconfdata/controller-scsi-inherit-model.xml
> @@ -0,0 +1,20 @@
> +<domain type='qemu'>
> + <name>guest</name>
> + <uuid>c7a5fdbd-edaf-9455-926a-d65c16db1809</uuid>
> + <memory unit='KiB'>219136</memory>
> + <vcpu placement='static'>8</vcpu>
> + <os>
> + <type arch='x86_64' machine='pc'>hvm</type>
> + </os>
> + <devices>
> + <emulator>/usr/bin/qemu-system-x86_64</emulator>
> + <controller type='scsi' index='0' model='virtio-scsi'/>
> + <disk type='file' device='disk'>
> + <driver name='qemu' type='qcow2'/>
> + <source file='/tmp/data.qcow2'/>
> + <target dev='sdy' bus='scsi'/>
> + </disk>
> + <controller type='usb' index='0' model='none'/>
> + <memballoon model='none'/>
> + </devices>
> +</domain>
> diff --git a/tests/qemuxmlconftest.c b/tests/qemuxmlconftest.c
> index 8e0f4bcb4f..7a441c1fa2 100644
> --- a/tests/qemuxmlconftest.c
> +++ b/tests/qemuxmlconftest.c
> @@ -1690,6 +1690,7 @@ mymain(void)
> DO_TEST_CAPS_LATEST_PARSE_ERROR("disk-scsi-product-length");
> DO_TEST_CAPS_LATEST("controller-virtio-scsi");
> DO_TEST_CAPS_LATEST("controller-scsi-auto");
> + DO_TEST_CAPS_LATEST("controller-scsi-inherit-model");
> DO_TEST_FULL("controller-scsi-default-unavailable", ".x86_64-latest",
> ARG_CAPS_ARCH, "x86_64",
> ARG_CAPS_VER, "latest",
ping
