* [PATCH qemu-server v5 2/4] hotplug: remove iothread with virtio-scsi controller together
2026-10-30 10:04 [PATCH qemu-server v5 0/4] hotplug: improve and fix cleanup/error handling Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 1/4] hotplug: scsi: only keep controller if a disk on it is still present Dominik Csapak
@ 2026-10-30 10:04 ` Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 3/4] hotplug: factor out cleanup of disk devices Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 4/4] hotplug: clean up disk devices/objects if adding them failed Dominik Csapak
3 siblings, 0 replies; 5+ messages in thread
From: Dominik Csapak @ 2026-10-30 10:04 UTC (permalink / raw)
To: pve-devel
With virtio-scsi-single, the iothread is used by the controller
'virtioscsiN' and not by the disk 'scsiN', but it was removed when
unplugging the disk (which was done after removal of the controller).
Remove the iothread together with the controller instead, and decide
whether to remove it by checking the iothreads that actually exist
instead of the config. This way, the controller can be unplugged
without having the config of its disk, which is necessary for cleaning
up after a failed hotplug in a following commit.
Since an 'iothread-<id>' object is only used by the device with that
id, it is safe to remove it once the device is gone.
Note that this now executes an additional qmp command for disks that
don't have an iothread in the config, but since this is not called that
often (once per disk config change) it should be ok.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
src/PVE/QemuServer.pm | 19 ++++++-------------
1 file changed, 6 insertions(+), 13 deletions(-)
diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 6ac3c685..38a4e4f8 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -3972,25 +3972,20 @@ sub vm_deviceunplug {
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
} elsif ($deviceid =~ m/^(virtio)(\d+)$/) {
- my $device = parse_drive($deviceid, $conf->{$deviceid});
-
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
qemu_drivedel($vmid, $deviceid);
- qemu_iothread_del($vmid, $deviceid, $device);
+ qemu_iothread_del($vmid, $deviceid);
} elsif ($deviceid =~ m/^(virtioscsi|scsihw)(\d+)$/) {
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid, 15);
+ qemu_iothread_del($vmid, $deviceid) if $deviceid =~ m/^virtioscsi\d+$/;
} elsif ($deviceid =~ m/^(scsi)(\d+)$/) {
- my $device = parse_drive($deviceid, $conf->{$deviceid});
-
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
qemu_drivedel($vmid, $deviceid);
+ # the iothread of a virtio-scsi-single disk belongs to its controller and is removed there
qemu_deletescsihw($conf, $vmid, $deviceid);
-
- qemu_iothread_del($vmid, "virtioscsi$device->{index}", $device)
- if $conf->{scsihw} && ($conf->{scsihw} eq 'virtio-scsi-single');
} elsif ($deviceid =~ m/^(net)(\d+)$/) {
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
@@ -4031,12 +4026,10 @@ sub qemu_iothread_add {
}
sub qemu_iothread_del {
- my ($vmid, $deviceid, $device) = @_;
+ my ($vmid, $deviceid) = @_;
- if ($device->{iothread}) {
- my $iothreads = vm_iothreads_list($vmid);
- qemu_objectdel($vmid, "iothread-$deviceid") if $iothreads->{"iothread-$deviceid"};
- }
+ my $iothreads = vm_iothreads_list($vmid);
+ qemu_objectdel($vmid, "iothread-$deviceid") if $iothreads->{"iothread-$deviceid"};
}
sub qemu_driveadd {
--
2.47.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH qemu-server v5 3/4] hotplug: factor out cleanup of disk devices
2026-10-30 10:04 [PATCH qemu-server v5 0/4] hotplug: improve and fix cleanup/error handling Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 1/4] hotplug: scsi: only keep controller if a disk on it is still present Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 2/4] hotplug: remove iothread with virtio-scsi controller together Dominik Csapak
@ 2026-10-30 10:04 ` Dominik Csapak
2026-10-30 10:04 ` [PATCH qemu-server v5 4/4] hotplug: clean up disk devices/objects if adding them failed Dominik Csapak
3 siblings, 0 replies; 5+ messages in thread
From: Dominik Csapak @ 2026-10-30 10:04 UTC (permalink / raw)
To: pve-devel
Unplugging a disk or SCSI controller removes the same parts that need to
be removed when hotplugging one of them failed. Factor this out into a
helper, so it can be reused for cleaning up after a failed hotplug in a
following commit.
For that case, the helper can warn instead of die on errors, so that
the remaining parts are still removed and the original error can be
reported.
Pass the parsed drive to qemu_deletescsihw instead of parsing it from
the config again, since a disk that failed to hotplug is still pending
and not in the config yet.
No functional change intended.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
src/PVE/QemuServer.pm | 46 +++++++++++++++++++++++++++++--------------
1 file changed, 31 insertions(+), 15 deletions(-)
diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 38a4e4f8..3811bff2 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -3854,6 +3854,32 @@ sub vm_devices_list {
return $devices;
}
+# clean up disks and their controllers (if unused afterwards)
+sub cleanup_disk {
+ my ($conf, $vmid, $deviceid, $device, $timeout, $noerr) = @_;
+
+ my $warn_or_die = sub {
+ my ($sub) = @_;
+ eval { $sub->(); };
+ if (my $err = $@) {
+ die $err if !$noerr;
+ warn $err;
+ }
+ };
+
+ $warn_or_die->(sub {
+ qemu_devicedel($vmid, $deviceid);
+ qemu_devicedelverify($vmid, $deviceid, $timeout);
+ });
+ $warn_or_die->(sub { qemu_drivedel($vmid, $deviceid); }) if $deviceid =~ m/^(virtio|scsi)\d+$/;
+ # the iothread of a virtio-scsi-single disk belongs to its controller and is removed there
+ $warn_or_die->(sub { qemu_deletescsihw($conf, $vmid, $device); }) if $deviceid =~ m/^scsi\d+$/;
+ $warn_or_die->(sub { qemu_iothread_del($vmid, $deviceid); })
+ if $deviceid =~ m/^virtio(scsi)?\d+$/;
+
+ return;
+}
+
sub vm_deviceplug {
my ($storecfg, $conf, $vmid, $deviceid, $device, $arch, $machine_type) = @_;
@@ -3972,20 +3998,12 @@ sub vm_deviceunplug {
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
} elsif ($deviceid =~ m/^(virtio)(\d+)$/) {
- qemu_devicedel($vmid, $deviceid);
- qemu_devicedelverify($vmid, $deviceid);
- qemu_drivedel($vmid, $deviceid);
- qemu_iothread_del($vmid, $deviceid);
+ cleanup_disk($conf, $vmid, $deviceid);
} elsif ($deviceid =~ m/^(virtioscsi|scsihw)(\d+)$/) {
- qemu_devicedel($vmid, $deviceid);
- qemu_devicedelverify($vmid, $deviceid, 15);
- qemu_iothread_del($vmid, $deviceid) if $deviceid =~ m/^virtioscsi\d+$/;
+ cleanup_disk($conf, $vmid, $deviceid, undef, 15);
} elsif ($deviceid =~ m/^(scsi)(\d+)$/) {
- qemu_devicedel($vmid, $deviceid);
- qemu_devicedelverify($vmid, $deviceid);
- qemu_drivedel($vmid, $deviceid);
- # the iothread of a virtio-scsi-single disk belongs to its controller and is removed there
- qemu_deletescsihw($conf, $vmid, $deviceid);
+ my $device = parse_drive($deviceid, $conf->{$deviceid});
+ cleanup_disk($conf, $vmid, $deviceid, $device);
} elsif ($deviceid =~ m/^(net)(\d+)$/) {
qemu_devicedel($vmid, $deviceid);
qemu_devicedelverify($vmid, $deviceid);
@@ -4124,9 +4142,7 @@ sub qemu_findorcreatescsihw {
}
sub qemu_deletescsihw {
- my ($conf, $vmid, $opt) = @_;
-
- my $device = parse_drive($opt, $conf->{$opt});
+ my ($conf, $vmid, $device) = @_;
if ($conf->{scsihw} && ($conf->{scsihw} eq 'virtio-scsi-single')) {
vm_deviceunplug($vmid, $conf, "virtioscsi$device->{index}");
--
2.47.3
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH qemu-server v5 4/4] hotplug: clean up disk devices/objects if adding them failed
2026-10-30 10:04 [PATCH qemu-server v5 0/4] hotplug: improve and fix cleanup/error handling Dominik Csapak
` (2 preceding siblings ...)
2026-10-30 10:04 ` [PATCH qemu-server v5 3/4] hotplug: factor out cleanup of disk devices Dominik Csapak
@ 2026-10-30 10:04 ` Dominik Csapak
3 siblings, 0 replies; 5+ messages in thread
From: Dominik Csapak @ 2026-10-30 10:04 UTC (permalink / raw)
To: pve-devel
Otherwise, parts of a disk are left over after a failed attempt to add
it. For VirtIO block disks this was the iothread. For SCSI disks, the
newly added controller was left over, including its iothread in case
of virtio-scsi-single, and if adding the controller itself failed, its
iothread too.
Use the same cleanup as for unplugging, so that all parts that might
have been added are removed again.
Also verify that a hotplugged SCSI disk actually shows up, like for
VirtIO block disks. Since errors of the HMP device_add command are not
reported, a failure was not noticed and the disk was moved from the
pending section into the config.
The failure can be tested by disabling hotplug, e.g. for an i440fx guest
one can use the following command line switches:
-global PIIX4_PM.acpi-root-pci-hotplug=off
-global PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off
-global pci-bridge.shpc=off
to disable hotplug on all PCI bridges and the PCI root bus.
The added regression tests would have failed without the code change.
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
src/PVE/QemuServer.pm | 37 ++++++++++++-------
src/test/hotplug/disk-add-fail.conf | 19 ++++++++++
src/test/hotplug/disk-add-fail.conf.expected | 10 +++++
.../disk-add-scsi-single-disk-fail.conf | 19 ++++++++++
...sk-add-scsi-single-disk-fail.conf.expected | 12 ++++++
.../hotplug/disk-add-scsi-single-fail.conf | 19 ++++++++++
.../disk-add-scsi-single-fail.conf.expected | 5 +++
7 files changed, 107 insertions(+), 14 deletions(-)
create mode 100644 src/test/hotplug/disk-add-fail.conf
create mode 100644 src/test/hotplug/disk-add-fail.conf.expected
create mode 100644 src/test/hotplug/disk-add-scsi-single-disk-fail.conf
create mode 100644 src/test/hotplug/disk-add-scsi-single-disk-fail.conf.expected
create mode 100644 src/test/hotplug/disk-add-scsi-single-fail.conf
create mode 100644 src/test/hotplug/disk-add-scsi-single-fail.conf.expected
diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 3811bff2..7285a297 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -3903,17 +3903,18 @@ sub vm_deviceplug {
PVE::QemuServer::USB::print_usbdevice_full($conf, $deviceid, $device, {}, $1 + 1),
);
} elsif ($deviceid =~ m/^(virtio)(\d+)$/) {
- qemu_iothread_add($vmid, $deviceid, $device);
-
- qemu_driveadd($storecfg, $vmid, $device);
my $devicefull =
print_drivedevice_full($storecfg, $conf, $vmid, $device, $arch, $machine_type);
- qemu_deviceadd($vmid, $devicefull);
- eval { qemu_deviceaddverify($vmid, $deviceid); };
+ eval {
+ qemu_iothread_add($vmid, $deviceid, $device);
+ qemu_driveadd($storecfg, $vmid, $device);
+ qemu_deviceadd($vmid, $devicefull);
+ qemu_deviceaddverify($vmid, $deviceid);
+ };
+
if (my $err = $@) {
- eval { qemu_drivedel($vmid, $deviceid); };
- warn $@ if $@;
+ cleanup_disk($conf, $vmid, $deviceid, $device, undef, 1);
die $err;
}
} elsif ($deviceid =~ m/^(virtioscsi|scsihw)(\d+)$/) {
@@ -3924,7 +3925,6 @@ sub vm_deviceplug {
my $devicefull = "$scsihw_type,id=$deviceid$pciaddr";
if ($deviceid =~ m/^virtioscsi(\d+)$/ && $device->{iothread}) {
- qemu_iothread_add($vmid, $deviceid, $device);
$devicefull .= ",iothread=iothread-$deviceid";
}
@@ -3932,18 +3932,27 @@ sub vm_deviceplug {
$devicefull .= ",num_queues=$device->{queues}";
}
- qemu_deviceadd($vmid, $devicefull);
- qemu_deviceaddverify($vmid, $deviceid);
+ eval {
+ qemu_iothread_add($vmid, $deviceid, $device) if $deviceid =~ m/^virtioscsi/;
+ qemu_deviceadd($vmid, $devicefull);
+ qemu_deviceaddverify($vmid, $deviceid);
+ };
+ if (my $err = $@) {
+ cleanup_disk($conf, $vmid, $deviceid, $device, undef, 1);
+ die $err;
+ }
} elsif ($deviceid =~ m/^(scsi)(\d+)$/) {
qemu_findorcreatescsihw($storecfg, $conf, $vmid, $device, $arch, $machine_type);
- qemu_driveadd($storecfg, $vmid, $device);
my $devicefull =
print_drivedevice_full($storecfg, $conf, $vmid, $device, $arch, $machine_type);
- eval { qemu_deviceadd($vmid, $devicefull); };
+ eval {
+ qemu_driveadd($storecfg, $vmid, $device);
+ qemu_deviceadd($vmid, $devicefull);
+ qemu_deviceaddverify($vmid, $deviceid);
+ };
if (my $err = $@) {
- eval { qemu_drivedel($vmid, $deviceid); };
- warn $@ if $@;
+ cleanup_disk($conf, $vmid, $deviceid, $device, undef, 1);
die $err;
}
} elsif ($deviceid =~ m/^(net)(\d+)$/) {
diff --git a/src/test/hotplug/disk-add-fail.conf b/src/test/hotplug/disk-add-fail.conf
new file mode 100644
index 00000000..800b113e
--- /dev/null
+++ b/src/test/hotplug/disk-add-fail.conf
@@ -0,0 +1,19 @@
+# TEST: a disk that does not show up after hotplug is detached again
+# FAIL_DEVICE_ADD: virtio1
+# EXPECTED_ERROR: virtio1: hotplug problem - error on hotplug device 'virtio1'
+# STAYS_PENDING: 1
+bootdisk: scsi0
+cores: 2
+machine: pc-i440fx-10.1
+memory: 2048
+name: hotplug
+net0: virtio=A2:C0:43:77:08:A0,bridge=vmbr0
+ostype: l26
+scsi0: local:8006/vm-8006-disk-0.qcow2,size=32G
+scsihw: virtio-scsi-pci
+smbios1: uuid=7b10d7af-b932-4c66-b2c3-3996152ec465
+sockets: 1
+vmgenid: c773c261-d800-4348-9f5d-167fadd53cf8
+
+[PENDING]
+virtio1: local:8006/vm-8006-disk-1.qcow2,iothread=1,size=32G
diff --git a/src/test/hotplug/disk-add-fail.conf.expected b/src/test/hotplug/disk-add-fail.conf.expected
new file mode 100644
index 00000000..30946720
--- /dev/null
+++ b/src/test/hotplug/disk-add-fail.conf.expected
@@ -0,0 +1,10 @@
+storage activate_volumes ["local:8006/vm-8006-disk-1.qcow2"]
+qmp object-add {"id":"iothread-virtio1","qom-type":"iothread"}
+qmp object-del {"id":"throttle-drive-virtio1"}
+qmp object-add {"id":"throttle-drive-virtio1","limits":{},"qom-type":"throttle-group"}
+qmp blockdev-add {"detect-zeroes":"on","discard":"ignore","driver":"throttle","file":{"cache":{"direct":true,"no-flush":false},"detect-zeroes":"on","discard":"ignore","driver":"qcow2","file":{"aio":"io_uring","cache":{"direct":true,"no-flush":false},"detect-zeroes":"on","discard":"ignore","driver":"file","filename":"/var/lib/vz/images/8006/vm-8006-disk-1.qcow2","node-name":"ef4c217a7f08cf59741edc1790023f5","read-only":false},"node-name":"ff4c217a7f08cf59741edc1790023f5","read-only":false},"node-name":"drive-virtio1","read-only":false,"throttle-group":"throttle-drive-virtio1"}
+hmp device_add driver=virtio-blk-pci,drive=drive-virtio1,id=virtio1,bus=pci.0,addr=0xb,iothread=iothread-virtio1,write-cache=on
+hmp device_del virtio1
+qmp blockdev-del {"node-name":"drive-virtio1"}
+qmp object-del {"id":"throttle-drive-virtio1"}
+qmp object-del {"id":"iothread-virtio1"}
diff --git a/src/test/hotplug/disk-add-scsi-single-disk-fail.conf b/src/test/hotplug/disk-add-scsi-single-disk-fail.conf
new file mode 100644
index 00000000..f493f589
--- /dev/null
+++ b/src/test/hotplug/disk-add-scsi-single-disk-fail.conf
@@ -0,0 +1,19 @@
+# TEST: a disk on virtio-scsi-single that does not show up after hotplug has its controller and iothread removed again
+# FAIL_DEVICE_ADD: scsi1
+# EXPECTED_ERROR: scsi1: hotplug problem - error on hotplug device 'scsi1'
+# STAYS_PENDING: 1
+bootdisk: scsi0
+cores: 2
+machine: pc-i440fx-10.1
+memory: 2048
+name: hotplug
+net0: virtio=A2:C0:43:77:08:A0,bridge=vmbr0
+ostype: l26
+scsi0: local:8006/vm-8006-disk-0.qcow2,iothread=1,size=32G
+scsihw: virtio-scsi-single
+smbios1: uuid=7b10d7af-b932-4c66-b2c3-3996152ec465
+sockets: 1
+vmgenid: c773c261-d800-4348-9f5d-167fadd53cf8
+
+[PENDING]
+scsi1: local:8006/vm-8006-disk-1.qcow2,iothread=1,size=32G
diff --git a/src/test/hotplug/disk-add-scsi-single-disk-fail.conf.expected b/src/test/hotplug/disk-add-scsi-single-disk-fail.conf.expected
new file mode 100644
index 00000000..a5da2480
--- /dev/null
+++ b/src/test/hotplug/disk-add-scsi-single-disk-fail.conf.expected
@@ -0,0 +1,12 @@
+storage activate_volumes ["local:8006/vm-8006-disk-1.qcow2"]
+qmp object-add {"id":"iothread-virtioscsi1","qom-type":"iothread"}
+hmp device_add driver=virtio-scsi-pci,id=virtioscsi1,bus=pci.3,addr=0x2,iothread=iothread-virtioscsi1
+qmp object-del {"id":"throttle-drive-scsi1"}
+qmp object-add {"id":"throttle-drive-scsi1","limits":{},"qom-type":"throttle-group"}
+qmp blockdev-add {"detect-zeroes":"on","discard":"ignore","driver":"throttle","file":{"cache":{"direct":true,"no-flush":false},"detect-zeroes":"on","discard":"ignore","driver":"qcow2","file":{"aio":"io_uring","cache":{"direct":true,"no-flush":false},"detect-zeroes":"on","discard":"ignore","driver":"file","filename":"/var/lib/vz/images/8006/vm-8006-disk-1.qcow2","node-name":"e70a10e5fb0473d3fc55686f720db61","read-only":false},"node-name":"f70a10e5fb0473d3fc55686f720db61","read-only":false},"node-name":"drive-scsi1","read-only":false,"throttle-group":"throttle-drive-scsi1"}
+hmp device_add driver=scsi-hd,bus=virtioscsi1.0,channel=0,scsi-id=0,lun=1,drive=drive-scsi1,id=scsi1,device_id=drive-scsi1,write-cache=on
+hmp device_del scsi1
+qmp blockdev-del {"node-name":"drive-scsi1"}
+qmp object-del {"id":"throttle-drive-scsi1"}
+hmp device_del virtioscsi1
+qmp object-del {"id":"iothread-virtioscsi1"}
diff --git a/src/test/hotplug/disk-add-scsi-single-fail.conf b/src/test/hotplug/disk-add-scsi-single-fail.conf
new file mode 100644
index 00000000..d9a9a30f
--- /dev/null
+++ b/src/test/hotplug/disk-add-scsi-single-fail.conf
@@ -0,0 +1,19 @@
+# TEST: a virtio-scsi-single controller that does not show up after hotplug has its iothread removed again
+# FAIL_DEVICE_ADD: virtioscsi1
+# EXPECTED_ERROR: scsi1: hotplug problem - error on hotplug device 'virtioscsi1'
+# STAYS_PENDING: 1
+bootdisk: scsi0
+cores: 2
+machine: pc-i440fx-10.1
+memory: 2048
+name: hotplug
+net0: virtio=A2:C0:43:77:08:A0,bridge=vmbr0
+ostype: l26
+scsi0: local:8006/vm-8006-disk-0.qcow2,iothread=1,size=32G
+scsihw: virtio-scsi-single
+smbios1: uuid=7b10d7af-b932-4c66-b2c3-3996152ec465
+sockets: 1
+vmgenid: c773c261-d800-4348-9f5d-167fadd53cf8
+
+[PENDING]
+scsi1: local:8006/vm-8006-disk-1.qcow2,iothread=1,size=32G
diff --git a/src/test/hotplug/disk-add-scsi-single-fail.conf.expected b/src/test/hotplug/disk-add-scsi-single-fail.conf.expected
new file mode 100644
index 00000000..fc291ec6
--- /dev/null
+++ b/src/test/hotplug/disk-add-scsi-single-fail.conf.expected
@@ -0,0 +1,5 @@
+storage activate_volumes ["local:8006/vm-8006-disk-1.qcow2"]
+qmp object-add {"id":"iothread-virtioscsi1","qom-type":"iothread"}
+hmp device_add driver=virtio-scsi-pci,id=virtioscsi1,bus=pci.3,addr=0x2,iothread=iothread-virtioscsi1
+hmp device_del virtioscsi1
+qmp object-del {"id":"iothread-virtioscsi1"}
--
2.47.3
^ permalink raw reply related [flat|nested] 5+ messages in thread