[pve-devel] [PATCH v2 0/4] <add meta info and bandaid for QEMU 6.1 and unpinned q35 machine backward compat

[pve-devel] [PATCH v2 0/4] <add meta info and bandaid for QEMU 6.1 and unpinned q35 machine backward compat

[Thomas Lamprecht]

changes v1 -> v2:
* move checks into own method
* ensure forced machine is parsed so that min_version can work
* only apply on `l26` ostype
* fix test file name and comment

v1 cover letter:

First add a new meta property that is currently exclusively set on new
VM creation and then read-only, initially add the creation time as UNIX
epoch and the QEMU version that was installed during installation
(thought about using the one on first start but that actually does not
gives any more guarantee, so just go for simple).

Use that information to band aid around a change regarding hotplug in
QEMU 6.1 that can affected older VMs on fresh start (migration and
rollback is covered by force-machine mechanisms as always already).

I'm not 100% convinced of the whole thing, albeit I see some merit in
the meta property even if we do not go with the last patch, anyhow, I
proposed this off-list to Dominik (and those thing is partly his idea
too), Wolfgang, Fabian and Stefan and none of them rejected the idea nor
communicated a better/more preferred alternative, so I went for it
(still not steaming from enthusiasm though)

Thomas Lamprecht (4):
  config: add new meta property withe creation time
  config: meta: also save the QEMU version installed during creation
  tests: cfg2cmd: add a few q35 related tests
  cfg2cmd: switch off ACPI hotplug on bridges for q35 VMs

 PVE/API2/Qemu.pm                              |  2 +
 PVE/QemuServer.pm                             | 73 +++++++++++++++++++
 .../q35-linux-hostpci-multifunction.conf.cmd  |  1 +
 test/cfg2cmd/q35-linux-hostpci.conf.cmd       |  1 +
 test/cfg2cmd/q35-simple-6.0.conf              | 13 ++++
 test/cfg2cmd/q35-simple-6.0.conf.cmd          | 28 +++++++
 test/cfg2cmd/q35-simple-7.0.conf              | 14 ++++
 test/cfg2cmd/q35-simple-7.0.conf.cmd          | 28 +++++++
 test/cfg2cmd/q35-simple-pinned-6.1.conf       | 13 ++++
 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd   | 28 +++++++
 test/cfg2cmd/q35-simple.conf                  | 13 ++++
 test/cfg2cmd/q35-simple.conf.cmd              | 29 ++++++++
 12 files changed, 243 insertions(+)
 create mode 100644 test/cfg2cmd/q35-simple-6.0.conf
 create mode 100644 test/cfg2cmd/q35-simple-6.0.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple-7.0.conf
 create mode 100644 test/cfg2cmd/q35-simple-7.0.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf
 create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple.conf
 create mode 100644 test/cfg2cmd/q35-simple.conf.cmd

-- 
2.30.2

[pve-devel] [PATCH v2 1/4] config: add new meta property withe creation time

[Thomas Lamprecht]

currently we only add the creation time (ctime), that was requested
as low priority wish from some users from time to time.

Note that the meta info is not available in the update API endpoints,
and at the moment the code should not change/add/delete it either in
any place.

We may want to update in on actions like clone or backup-restore in
the future, e.g., to also save the time of that event and possibly
the original source VMID, put that can be thought out later.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---

no changes

 PVE/API2/Qemu.pm  |  2 ++
 PVE/QemuServer.pm | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index 1ac81e2..b479811 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -708,6 +708,8 @@ __PACKAGE__->register_method({
 		my $conf = $param;
 		my $arch = PVE::QemuServer::get_vm_arch($conf);
 
+		$conf->{meta} = PVE::QemuServer::new_meta_info_string();
+
 		my $vollist = [];
 		eval {
 		    $vollist = &$create_disks($rpcenv, $authuser, $conf, $arch, $storecfg, $vmid, $pool, $param, $storage);
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index fbc0d46..8b98e69 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -286,6 +286,15 @@ my $rng_fmt = {
     },
 };
 
+my $meta_info_fmt = {
+    'ctime' => {
+	type => 'integer',
+	description => "The guest creation timestamp as UNIX epoch time",
+	minimum => 0,
+	optional => 1,
+    },
+};
+
 my $confdesc = {
     onboot => {
 	optional => 1,
@@ -707,6 +716,12 @@ EODESCR
 	description => "Configure a VirtIO-based Random Number Generator.",
 	optional => 1,
     },
+    meta => {
+	type => 'string',
+	format => $meta_info_fmt,
+	description => "Some (read-only) meta-information about this guest.",
+	optional => 1,
+    },
 };
 
 my $cicustom_fmt = {
@@ -2107,6 +2122,27 @@ sub parse_rng {
     return $res;
 }
 
+sub parse_meta_info {
+    my ($value) = @_;
+
+    return if !$value;
+
+    my $res = eval { parse_property_string($meta_info_fmt, $value) };
+    warn $@ if $@;
+    return $res;
+}
+
+sub new_meta_info_string {
+    my () = @_; # for now do not allow to override any value
+
+    return PVE::JSONSchema::print_property_string(
+	{
+	    ctime => "". int(time()),
+	},
+	$meta_info_fmt
+    );
+}
+
 PVE::JSONSchema::register_format('pve-qm-usb-device', \&verify_usb_device);
 sub verify_usb_device {
     my ($value, $noerr) = @_;
@@ -2128,6 +2164,7 @@ sub json_config_properties {
 	vmstate => 1,
 	runningmachine => 1,
 	runningcpu => 1,
+	meta => 1,
     };
 
     foreach my $opt (keys %$confdesc) {
-- 
2.30.2

[pve-devel] [PATCH v2 2/4] config: meta: also save the QEMU version installed during creation

[Thomas Lamprecht]

This is intended to be used to apply some workarounds for the
non-windows ostyped VMs which we'd still like to not pin on a
specific machine version, as normally Linux et al. can cope with such
changes on fresh boot just fine and until now this was a once every
few year issue (albeit systemd's "predictable" interface naming has
some potential to pick up on churn frequency).

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---

no changes

 PVE/QemuServer.pm | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 8b98e69..dc06171 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -293,6 +293,12 @@ my $meta_info_fmt = {
 	minimum => 0,
 	optional => 1,
     },
+    'creation-qemu' => {
+	type => 'string',
+	description => "The QEMU (machine) version from the time this VM was created.",
+	pattern => '\d+(\.\d+)+',
+	optional => 1,
+    },
 };
 
 my $confdesc = {
@@ -2137,6 +2143,7 @@ sub new_meta_info_string {
 
     return PVE::JSONSchema::print_property_string(
 	{
+	    'creation-qemu' => kvm_user_version(),
 	    ctime => "". int(time()),
 	},
 	$meta_info_fmt
-- 
2.30.2

[pve-devel] [PATCH v2 3/4] tests: cfg2cmd: add a few q35 related tests

[Thomas Lamprecht]

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---

changes v1 -> v2:
* fix test name and comment (wrongly used 6.1 instead of 7.0)

 test/cfg2cmd/q35-simple-6.0.conf            | 13 ++++++++++
 test/cfg2cmd/q35-simple-6.0.conf.cmd        | 28 +++++++++++++++++++++
 test/cfg2cmd/q35-simple-7.0.conf            | 14 +++++++++++
 test/cfg2cmd/q35-simple-7.0.conf.cmd        | 28 +++++++++++++++++++++
 test/cfg2cmd/q35-simple-pinned-6.1.conf     | 13 ++++++++++
 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd | 28 +++++++++++++++++++++
 test/cfg2cmd/q35-simple.conf                | 13 ++++++++++
 test/cfg2cmd/q35-simple.conf.cmd            | 28 +++++++++++++++++++++
 8 files changed, 165 insertions(+)
 create mode 100644 test/cfg2cmd/q35-simple-6.0.conf
 create mode 100644 test/cfg2cmd/q35-simple-6.0.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple-7.0.conf
 create mode 100644 test/cfg2cmd/q35-simple-7.0.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf
 create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
 create mode 100644 test/cfg2cmd/q35-simple.conf
 create mode 100644 test/cfg2cmd/q35-simple.conf.cmd

diff --git a/test/cfg2cmd/q35-simple-6.0.conf b/test/cfg2cmd/q35-simple-6.0.conf
new file mode 100644
index 0000000..70426b3
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-6.0.conf
@@ -0,0 +1,13 @@
+# TEST: Config with q35, Linux & nothing much else but on 6.0
+# QEMU_VERSION: 6.0.0
+bios: ovmf
+bootdisk: scsi0
+cores: 2
+efidisk0: local:100/vm-100-disk-1.qcow2,size=128K
+machine: q35
+memory: 512
+net0: virtio=2E:01:68:F9:9C:87,bridge=vmbr0
+ostype: l26
+scsihw: virtio-scsi-pci
+smbios1: uuid=3dd750ce-d910-44d0-9493-525c0be4e687
+vmgenid: 54d1c06c-8f5b-440f-b5b2-6eab1380e13d
diff --git a/test/cfg2cmd/q35-simple-6.0.conf.cmd b/test/cfg2cmd/q35-simple-6.0.conf.cmd
new file mode 100644
index 0000000..5045caf
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-6.0.conf.cmd
@@ -0,0 +1,28 @@
+/usr/bin/kvm \
+  -id 8006 \
+  -name vm8006 \
+  -no-shutdown \
+  -chardev 'socket,id=qmp,path=/var/run/qemu-server/8006.qmp,server=on,wait=off' \
+  -mon 'chardev=qmp,mode=control' \
+  -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
+  -mon 'chardev=qmp-event,mode=control' \
+  -pidfile /var/run/qemu-server/8006.pid \
+  -daemonize \
+  -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
+  -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
+  -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -smp '2,sockets=1,cores=2,maxcpus=2' \
+  -nodefaults \
+  -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
+  -vnc 'unix:/var/run/qemu-server/8006.vnc,password=on' \
+  -cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep \
+  -m 512 \
+  -readconfig /usr/share/qemu-server/pve-q35-4.0.cfg \
+  -device 'vmgenid,guid=54d1c06c-8f5b-440f-b5b2-6eab1380e13d' \
+  -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' \
+  -device 'VGA,id=vga,bus=pcie.0,addr=0x1' \
+  -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
+  -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
+  -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -machine 'type=q35+pve0'
diff --git a/test/cfg2cmd/q35-simple-7.0.conf b/test/cfg2cmd/q35-simple-7.0.conf
new file mode 100644
index 0000000..4618e23
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-7.0.conf
@@ -0,0 +1,14 @@
+# TEST: Config with q35, Linux & nothing much else but on 7.0
+# QEMU_VERSION: 7.0.0
+bios: ovmf
+bootdisk: scsi0
+cores: 2
+efidisk0: local:100/vm-100-disk-1.qcow2,size=128K
+machine: q35
+meta: creation-qemu=6.1
+memory: 512
+net0: virtio=2E:01:68:F9:9C:87,bridge=vmbr0
+ostype: l26
+scsihw: virtio-scsi-pci
+smbios1: uuid=3dd750ce-d910-44d0-9493-525c0be4e687
+vmgenid: 54d1c06c-8f5b-440f-b5b2-6eab1380e13d
diff --git a/test/cfg2cmd/q35-simple-7.0.conf.cmd b/test/cfg2cmd/q35-simple-7.0.conf.cmd
new file mode 100644
index 0000000..5045caf
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-7.0.conf.cmd
@@ -0,0 +1,28 @@
+/usr/bin/kvm \
+  -id 8006 \
+  -name vm8006 \
+  -no-shutdown \
+  -chardev 'socket,id=qmp,path=/var/run/qemu-server/8006.qmp,server=on,wait=off' \
+  -mon 'chardev=qmp,mode=control' \
+  -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
+  -mon 'chardev=qmp-event,mode=control' \
+  -pidfile /var/run/qemu-server/8006.pid \
+  -daemonize \
+  -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
+  -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
+  -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -smp '2,sockets=1,cores=2,maxcpus=2' \
+  -nodefaults \
+  -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
+  -vnc 'unix:/var/run/qemu-server/8006.vnc,password=on' \
+  -cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep \
+  -m 512 \
+  -readconfig /usr/share/qemu-server/pve-q35-4.0.cfg \
+  -device 'vmgenid,guid=54d1c06c-8f5b-440f-b5b2-6eab1380e13d' \
+  -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' \
+  -device 'VGA,id=vga,bus=pcie.0,addr=0x1' \
+  -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
+  -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
+  -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -machine 'type=q35+pve0'
diff --git a/test/cfg2cmd/q35-simple-pinned-6.1.conf b/test/cfg2cmd/q35-simple-pinned-6.1.conf
new file mode 100644
index 0000000..9ecfe00
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-pinned-6.1.conf
@@ -0,0 +1,13 @@
+# TEST: Config with q35, Linux & nothing much else
+#
+bios: ovmf
+bootdisk: scsi0
+cores: 2
+efidisk0: local:100/vm-100-disk-1.qcow2,size=128K
+machine: pc-q35-6.1
+memory: 512
+net0: virtio=2E:01:68:F9:9C:87,bridge=vmbr0
+ostype: l26
+scsihw: virtio-scsi-pci
+smbios1: uuid=3dd750ce-d910-44d0-9493-525c0be4e687
+vmgenid: 54d1c06c-8f5b-440f-b5b2-6eab1380e13d
diff --git a/test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd b/test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
new file mode 100644
index 0000000..26dfaaa
--- /dev/null
+++ b/test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
@@ -0,0 +1,28 @@
+/usr/bin/kvm \
+  -id 8006 \
+  -name vm8006 \
+  -no-shutdown \
+  -chardev 'socket,id=qmp,path=/var/run/qemu-server/8006.qmp,server=on,wait=off' \
+  -mon 'chardev=qmp,mode=control' \
+  -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
+  -mon 'chardev=qmp-event,mode=control' \
+  -pidfile /var/run/qemu-server/8006.pid \
+  -daemonize \
+  -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
+  -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
+  -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -smp '2,sockets=1,cores=2,maxcpus=2' \
+  -nodefaults \
+  -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
+  -vnc 'unix:/var/run/qemu-server/8006.vnc,password=on' \
+  -cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep \
+  -m 512 \
+  -readconfig /usr/share/qemu-server/pve-q35-4.0.cfg \
+  -device 'vmgenid,guid=54d1c06c-8f5b-440f-b5b2-6eab1380e13d' \
+  -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' \
+  -device 'VGA,id=vga,bus=pcie.0,addr=0x1' \
+  -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
+  -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
+  -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -machine 'type=pc-q35-6.1+pve0'
diff --git a/test/cfg2cmd/q35-simple.conf b/test/cfg2cmd/q35-simple.conf
new file mode 100644
index 0000000..21f7812
--- /dev/null
+++ b/test/cfg2cmd/q35-simple.conf
@@ -0,0 +1,13 @@
+# TEST: Config with q35, Linux & nothing much else
+#
+bios: ovmf
+bootdisk: scsi0
+cores: 2
+efidisk0: local:100/vm-100-disk-1.qcow2,size=128K
+machine: q35
+memory: 512
+net0: virtio=2E:01:68:F9:9C:87,bridge=vmbr0
+ostype: l26
+scsihw: virtio-scsi-pci
+smbios1: uuid=3dd750ce-d910-44d0-9493-525c0be4e687
+vmgenid: 54d1c06c-8f5b-440f-b5b2-6eab1380e13d
diff --git a/test/cfg2cmd/q35-simple.conf.cmd b/test/cfg2cmd/q35-simple.conf.cmd
new file mode 100644
index 0000000..5045caf
--- /dev/null
+++ b/test/cfg2cmd/q35-simple.conf.cmd
@@ -0,0 +1,28 @@
+/usr/bin/kvm \
+  -id 8006 \
+  -name vm8006 \
+  -no-shutdown \
+  -chardev 'socket,id=qmp,path=/var/run/qemu-server/8006.qmp,server=on,wait=off' \
+  -mon 'chardev=qmp,mode=control' \
+  -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
+  -mon 'chardev=qmp-event,mode=control' \
+  -pidfile /var/run/qemu-server/8006.pid \
+  -daemonize \
+  -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
+  -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
+  -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -smp '2,sockets=1,cores=2,maxcpus=2' \
+  -nodefaults \
+  -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
+  -vnc 'unix:/var/run/qemu-server/8006.vnc,password=on' \
+  -cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep \
+  -m 512 \
+  -readconfig /usr/share/qemu-server/pve-q35-4.0.cfg \
+  -device 'vmgenid,guid=54d1c06c-8f5b-440f-b5b2-6eab1380e13d' \
+  -device 'usb-tablet,id=tablet,bus=ehci.0,port=1' \
+  -device 'VGA,id=vga,bus=pcie.0,addr=0x1' \
+  -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
+  -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
+  -netdev 'type=tap,id=net0,ifname=tap8006i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on' \
+  -device 'virtio-net-pci,mac=2E:01:68:F9:9C:87,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
+  -machine 'type=q35+pve0'
-- 
2.30.2

[pve-devel] [PATCH v2 4/4] cfg2cmd: switch off ACPI hotplug on bridges for q35 VMs

[Thomas Lamprecht]

See commit 17858a1695 (hw/acpi/ich9: Set ACPI PCI hot-plug as default
on Q35)[0] in upstream QEMU repository for details about why the change
was made.

As that change affects systemds predictable interface naming[1],
e.g., by going from a previously `ens18` name to `enp6s18`, it may
have rather bad effects for users that did not setup some .link files
to enforce a specific naming by an more stable information like the
NIC's MAC-Address

The alternative would be making the preferred mode of hotplug an
option like `hotplug-mode=<acpi|pcie>`, but it does not seems like
one would like to change that much in the first place...

Note the changes to the tests and especially the tests with q35
machines that did not change.

[0]: https://gitlab.com/qemu-project/qemu/-/commit/17858a1695
[1]: https://www.freedesktop.org/software/systemd/man/systemd.net-naming-scheme.html#Naming

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---

changes v1 -> v2:
* move checks into own method to avoid crowding cfg2cmd further
* ensure forced machine is parsed so that min_version can work
* only apply on `l26` ostype as non-linux machines normally are not
  affected by this change on fresh start

 PVE/QemuServer.pm                             | 29 +++++++++++++++++++
 .../q35-linux-hostpci-multifunction.conf.cmd  |  1 +
 test/cfg2cmd/q35-linux-hostpci.conf.cmd       |  1 +
 test/cfg2cmd/q35-simple.conf.cmd              |  1 +
 4 files changed, 32 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index dc06171..091d103 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -2150,6 +2150,31 @@ sub new_meta_info_string {
     );
 }
 
+sub qemu_created_version_fixups {
+    my ($conf, $forcemachine, $kvmver) = @_;
+
+    my $meta = parse_meta_info($conf->{meta}) // {};
+    my $forced_vers = PVE::QemuServer::Machine::extract_version($forcemachine);
+
+    # check if we need to apply some handling for VMs that always use the latest machine version but
+    # had a machine version transition happen that affected HW such that, e.g., an OS config change
+    # would be required (we do not want to pin machine version for non-windows OS type)
+    if (
+	(!defined($conf->{machine}) || $conf->{machine} =~ m/^(?:pc|q35|virt)$/) # non-versioned machine
+	&& (!defined($meta->{'creation-qemu'}) || !min_version($meta->{'creation-qemu'}, 6, 1)) # created before 6.1
+	&& (!$forced_vers || min_version($forced_vers, 6, 1)) # handle snapshot-rollback/migrations
+	&& min_version($kvmver, 6, 1) # only need to apply the change since 6.1
+    ) {
+	my $q35 = PVE::QemuServer::Machine::machine_type_is_q35($conf);
+	if ($q35 && $conf->{ostype} && $conf->{ostype} eq 'l26') {
+	    # this changed to default-on in Q 6.1 for q35 machines, it will mess with PCI slot view
+	    # and thus with the predictable interface naming of systemd
+	    return ['-global', 'ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off'];
+	}
+    }
+    return;
+}
+
 PVE::JSONSchema::register_format('pve-qm-usb-device', \&verify_usb_device);
 sub verify_usb_device {
     my ($value, $noerr) = @_;
@@ -3546,6 +3571,10 @@ sub config_to_command {
 	}
     }
 
+    if (defined(my $fixups = qemu_created_version_fixups($conf, $forcemachine, $kvmver))) {
+	push @$cmd, $fixups->@*;
+    }
+
     if ($conf->{vmgenid}) {
 	push @$devices, '-device', 'vmgenid,guid='.$conf->{vmgenid};
     }
diff --git a/test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd b/test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd
index 1f9beda..d393906 100644
--- a/test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd
+++ b/test/cfg2cmd/q35-linux-hostpci-multifunction.conf.cmd
@@ -11,6 +11,7 @@
   -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
   -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
   -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -global 'ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' \
   -smp '2,sockets=2,cores=1,maxcpus=2' \
   -nodefaults \
   -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
diff --git a/test/cfg2cmd/q35-linux-hostpci.conf.cmd b/test/cfg2cmd/q35-linux-hostpci.conf.cmd
index dd1bece..5da5c35 100644
--- a/test/cfg2cmd/q35-linux-hostpci.conf.cmd
+++ b/test/cfg2cmd/q35-linux-hostpci.conf.cmd
@@ -11,6 +11,7 @@
   -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
   -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
   -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -global 'ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' \
   -smp '2,sockets=2,cores=1,maxcpus=2' \
   -nodefaults \
   -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
diff --git a/test/cfg2cmd/q35-simple.conf.cmd b/test/cfg2cmd/q35-simple.conf.cmd
index 5045caf..1c97a89 100644
--- a/test/cfg2cmd/q35-simple.conf.cmd
+++ b/test/cfg2cmd/q35-simple.conf.cmd
@@ -11,6 +11,7 @@
   -smbios 'type=1,uuid=3dd750ce-d910-44d0-9493-525c0be4e687' \
   -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
   -drive 'if=pflash,unit=1,format=qcow2,id=drive-efidisk0,file=/var/lib/vz/images/100/vm-100-disk-1.qcow2' \
+  -global 'ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' \
   -smp '2,sockets=1,cores=2,maxcpus=2' \
   -nodefaults \
   -boot 'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg' \
-- 
2.30.2

Re: [pve-devel] [PATCH v2 0/4] <add meta info and bandaid for QEMU 6.1 and unpinned q35 machine backward compat

[Dominik Csapak]

LGTM, tested fine and worked as advertised

if we want to go forward this way:

Reviewed-by: Dominik Csapak <d.csapak@proxmox.com>
Tested-by: Dominik Csapak <d.csapak@proxmox.com>

On 11/3/21 16:58, Thomas Lamprecht wrote:
> changes v1 -> v2:
> * move checks into own method
> * ensure forced machine is parsed so that min_version can work
> * only apply on `l26` ostype
> * fix test file name and comment
> 
> v1 cover letter:
> 
> First add a new meta property that is currently exclusively set on new
> VM creation and then read-only, initially add the creation time as UNIX
> epoch and the QEMU version that was installed during installation
> (thought about using the one on first start but that actually does not
> gives any more guarantee, so just go for simple).
> 
> Use that information to band aid around a change regarding hotplug in
> QEMU 6.1 that can affected older VMs on fresh start (migration and
> rollback is covered by force-machine mechanisms as always already).
> 
> I'm not 100% convinced of the whole thing, albeit I see some merit in
> the meta property even if we do not go with the last patch, anyhow, I
> proposed this off-list to Dominik (and those thing is partly his idea
> too), Wolfgang, Fabian and Stefan and none of them rejected the idea nor
> communicated a better/more preferred alternative, so I went for it
> (still not steaming from enthusiasm though)
> 
> Thomas Lamprecht (4):
>    config: add new meta property withe creation time
>    config: meta: also save the QEMU version installed during creation
>    tests: cfg2cmd: add a few q35 related tests
>    cfg2cmd: switch off ACPI hotplug on bridges for q35 VMs
> 
>   PVE/API2/Qemu.pm                              |  2 +
>   PVE/QemuServer.pm                             | 73 +++++++++++++++++++
>   .../q35-linux-hostpci-multifunction.conf.cmd  |  1 +
>   test/cfg2cmd/q35-linux-hostpci.conf.cmd       |  1 +
>   test/cfg2cmd/q35-simple-6.0.conf              | 13 ++++
>   test/cfg2cmd/q35-simple-6.0.conf.cmd          | 28 +++++++
>   test/cfg2cmd/q35-simple-7.0.conf              | 14 ++++
>   test/cfg2cmd/q35-simple-7.0.conf.cmd          | 28 +++++++
>   test/cfg2cmd/q35-simple-pinned-6.1.conf       | 13 ++++
>   test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd   | 28 +++++++
>   test/cfg2cmd/q35-simple.conf                  | 13 ++++
>   test/cfg2cmd/q35-simple.conf.cmd              | 29 ++++++++
>   12 files changed, 243 insertions(+)
>   create mode 100644 test/cfg2cmd/q35-simple-6.0.conf
>   create mode 100644 test/cfg2cmd/q35-simple-6.0.conf.cmd
>   create mode 100644 test/cfg2cmd/q35-simple-7.0.conf
>   create mode 100644 test/cfg2cmd/q35-simple-7.0.conf.cmd
>   create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf
>   create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
>   create mode 100644 test/cfg2cmd/q35-simple.conf
>   create mode 100644 test/cfg2cmd/q35-simple.conf.cmd
> 

Re: [pve-devel] [PATCH v2 0/4] <add meta info and bandaid for QEMU 6.1 and unpinned q35 machine backward compat

[Wolfgang Bumiller]

I guess that's okay...

for all those weirdos who don't create `.link` files to pin their
network interface names in place :-P

Acked-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

On Wed, Nov 03, 2021 at 04:58:08PM +0100, Thomas Lamprecht wrote:
> changes v1 -> v2:
> * move checks into own method
> * ensure forced machine is parsed so that min_version can work
> * only apply on `l26` ostype
> * fix test file name and comment
> 
> v1 cover letter:
> 
> First add a new meta property that is currently exclusively set on new
> VM creation and then read-only, initially add the creation time as UNIX
> epoch and the QEMU version that was installed during installation
> (thought about using the one on first start but that actually does not
> gives any more guarantee, so just go for simple).
> 
> Use that information to band aid around a change regarding hotplug in
> QEMU 6.1 that can affected older VMs on fresh start (migration and
> rollback is covered by force-machine mechanisms as always already).
> 
> I'm not 100% convinced of the whole thing, albeit I see some merit in
> the meta property even if we do not go with the last patch, anyhow, I
> proposed this off-list to Dominik (and those thing is partly his idea
> too), Wolfgang, Fabian and Stefan and none of them rejected the idea nor
> communicated a better/more preferred alternative, so I went for it
> (still not steaming from enthusiasm though)
> 
> Thomas Lamprecht (4):
>   config: add new meta property withe creation time
>   config: meta: also save the QEMU version installed during creation
>   tests: cfg2cmd: add a few q35 related tests
>   cfg2cmd: switch off ACPI hotplug on bridges for q35 VMs
> 
>  PVE/API2/Qemu.pm                              |  2 +
>  PVE/QemuServer.pm                             | 73 +++++++++++++++++++
>  .../q35-linux-hostpci-multifunction.conf.cmd  |  1 +
>  test/cfg2cmd/q35-linux-hostpci.conf.cmd       |  1 +
>  test/cfg2cmd/q35-simple-6.0.conf              | 13 ++++
>  test/cfg2cmd/q35-simple-6.0.conf.cmd          | 28 +++++++
>  test/cfg2cmd/q35-simple-7.0.conf              | 14 ++++
>  test/cfg2cmd/q35-simple-7.0.conf.cmd          | 28 +++++++
>  test/cfg2cmd/q35-simple-pinned-6.1.conf       | 13 ++++
>  test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd   | 28 +++++++
>  test/cfg2cmd/q35-simple.conf                  | 13 ++++
>  test/cfg2cmd/q35-simple.conf.cmd              | 29 ++++++++
>  12 files changed, 243 insertions(+)
>  create mode 100644 test/cfg2cmd/q35-simple-6.0.conf
>  create mode 100644 test/cfg2cmd/q35-simple-6.0.conf.cmd
>  create mode 100644 test/cfg2cmd/q35-simple-7.0.conf
>  create mode 100644 test/cfg2cmd/q35-simple-7.0.conf.cmd
>  create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf
>  create mode 100644 test/cfg2cmd/q35-simple-pinned-6.1.conf.cmd
>  create mode 100644 test/cfg2cmd/q35-simple.conf
>  create mode 100644 test/cfg2cmd/q35-simple.conf.cmd
> 
> -- 
> 2.30.2

[pve-devel] applied-series: [PATCH v2 0/4] <add meta info and bandaid for QEMU 6.1 and unpinned q35 machine backward compat

[Thomas Lamprecht]

On 03.11.21 16:58, Thomas Lamprecht wrote:
>   config: add new meta property withe creation time
>   config: meta: also save the QEMU version installed during creation
>   tests: cfg2cmd: add a few q35 related tests
>   cfg2cmd: switch off ACPI hotplug on bridges for q35 VMs


applied with Dominik's R-b/T-b and Wolfgang's A-b, thanks for checking this out!