[pve-devel] [PATCH qemu-server 2/2] fix #3352: templates: minimize config when starting templates

[Dominik Csapak <d.csapak@proxmox.com>]

templates can only be started in context of a pbs backup, and there we
don't need or want to use most of the config, since they cannot be
started normally anyway.

We minimize the config by copying some specific relevant options (see
the comments for why the options were chosen) and all disk
configurations.

Since we change the qemu commandline for templates, we now have to adapt
the tests involving templates.

Without this, users can get into a situation where the template cannot
be backed up when there are some resources not available (such as cpu
cores, kvm, pci devices, etc.) even if the backup process does not need
them.

This change has some nice side effects, such as we don't need to
allocate the full amount of memory anymore for templates that have a
hostpci device configured, the configured bridges don't have to exist,
etc.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
this replaces: "fix #5543: pci: don't use pci devices when starting templates"
https://lists.proxmox.com/pipermail/pve-devel/2024-June/064238.html


 PVE/QemuServer.pm                             | 25 +++++++++++++
 test/cfg2cmd/efi-raw-template.conf.cmd        |  9 +++--
 .../q35-linux-hostpci-template.conf.cmd       | 35 ++++++-------------
 test/cfg2cmd/simple1-template.conf.cmd        | 18 ++++------
 4 files changed, 46 insertions(+), 41 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 7815b608..0d998798 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -3497,6 +3497,28 @@ sub config_to_command {
     my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
         $live_restore_backing) = @_;
 
+    # minimize config for templates, they can only start for backup,
+    # so most options besides the disks are irrelevant
+    if (PVE::QemuConfig->is_template($conf)) {
+	my $newconf = {
+	    template => 1, # in case below code checks that
+	    kvm => 0, # to prevent an error on hosts without virtualization extensions
+	    vga => 'none', # to not start a vnc server
+	    scsihw => $conf->{scsihw}, # so that the scsi disks are correctly added
+	    bios => $conf->{bios}, # so efidisk gets included if it exists
+	    name => $conf->{name}, # so it's correct in the process list
+	};
+
+	# copy all disks over
+	for my $device (PVE::QemuServer::Drive::valid_drive_names()) {
+	    $newconf->{$device} = $conf->{$device};
+	}
+
+	# remaining configs stay default
+
+	$conf = $newconf;
+    }
+
     my ($globalFlags, $machineFlags, $rtcFlags) = ([], [], []);
     my $devices = [];
     my $bridges = {};
@@ -6137,6 +6159,9 @@ sub get_vm_volumes {
 sub cleanup_pci_devices {
     my ($vmid, $conf) = @_;
 
+    # templates don't use pci devices
+    return if $conf->{template};
+
     foreach my $key (keys %$conf) {
 	next if $key !~ m/^hostpci(\d+)$/;
 	my $hostpciindex = $1;
diff --git a/test/cfg2cmd/efi-raw-template.conf.cmd b/test/cfg2cmd/efi-raw-template.conf.cmd
index b1d4d1f6..3e90c335 100644
--- a/test/cfg2cmd/efi-raw-template.conf.cmd
+++ b/test/cfg2cmd/efi-raw-template.conf.cmd
@@ -8,21 +8,20 @@
   -mon 'chardev=qmp-event,mode=control' \
   -pidfile /var/run/qemu-server/8006.pid \
   -daemonize \
-  -smbios 'type=1,uuid=7b10d7af-b932-4c66-b2c3-3996152ec465' \
   -drive 'if=pflash,unit=0,format=raw,readonly=on,file=/usr/share/pve-edk2-firmware//OVMF_CODE.fd' \
   -drive 'if=pflash,unit=1,id=drive-efidisk0,format=raw,file=/var/lib/vz/images/100/base-disk-100-0.raw,size=131072,readonly=on' \
   -smp '1,sockets=1,cores=1,maxcpus=1' \
   -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 \
+  -vga none \
+  -nographic \
+  -cpu qemu64 \
   -m 512 \
   -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' \
   -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' \
   -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' \
   -device 'usb-tablet,id=tablet,bus=uhci.0,port=1' \
-  -device 'VGA,id=vga,bus=pci.0,addr=0x2' \
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
-  -machine 'type=pc+pve0' \
+  -machine 'accel=tcg,type=pc+pve0' \
   -snapshot
diff --git a/test/cfg2cmd/q35-linux-hostpci-template.conf.cmd b/test/cfg2cmd/q35-linux-hostpci-template.conf.cmd
index f9b9bf69..cda10630 100644
--- a/test/cfg2cmd/q35-linux-hostpci-template.conf.cmd
+++ b/test/cfg2cmd/q35-linux-hostpci-template.conf.cmd
@@ -8,38 +8,23 @@
   -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,id=drive-efidisk0,format=qcow2,file=/var/lib/vz/images/100/base-100-disk-1.qcow2,readonly=on' \
-  -global 'ICH9-LPC.acpi-pci-hotplug-with-bridge-support=off' \
-  -smp '2,sockets=2,cores=1,maxcpus=2' \
+  -smp '1,sockets=1,cores=1,maxcpus=1' \
   -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 \
+  -vga none \
+  -nographic \
+  -cpu qemu64 \
   -m 512 \
-  -object 'memory-backend-ram,id=ram-node0,size=256M' \
-  -numa 'node,nodeid=0,cpus=0,memdev=ram-node0' \
-  -object 'memory-backend-ram,id=ram-node1,size=256M' \
-  -numa 'node,nodeid=1,cpus=1,memdev=ram-node1' \
-  -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 'vfio-pci,host=0000:00:ff.1,id=hostpci0,bus=pci.0,addr=0x10' \
-  -device 'vfio-pci,host=0000:d0:13.0,id=hostpci1,bus=ich9-pcie-port-2,addr=0x0' \
-  -device 'vfio-pci,host=0000:00:f4.0,id=hostpci2,bus=pci.0,addr=0x1b' \
-  -device 'vfio-pci,host=0000:d0:15.1,id=hostpci3,bus=ich9-pcie-port-4,addr=0x0' \
-  -device 'pcie-root-port,id=ich9-pcie-port-5,addr=10.0,x-speed=16,x-width=32,multifunction=on,bus=pcie.0,port=5,chassis=5' \
-  -device 'vfio-pci,host=0000:d0:17.0,id=hostpci4,bus=ich9-pcie-port-5,addr=0x0,rombar=0' \
-  -device 'pcie-root-port,id=ich9-pcie-port-8,addr=10.3,x-speed=16,x-width=32,multifunction=on,bus=pcie.0,port=8,chassis=8' \
-  -device 'vfio-pci,host=0000:d0:15.2,id=hostpci7,bus=ich9-pcie-port-8,addr=0x0' \
-  -device 'VGA,id=vga,bus=pcie.0,addr=0x1' \
+  -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' \
+  -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' \
+  -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' \
+  -device 'usb-tablet,id=tablet,bus=uhci.0,port=1' \
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3,free-page-reporting=on' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' \
   -drive 'file=/var/lib/vz/images/100/base-100-disk-2.raw,if=none,id=drive-scsi0,format=raw,cache=none,aio=io_uring,detect-zeroes=on,readonly=on' \
-  -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' \
-  -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,rx_queue_size=1024,tx_queue_size=256,bootindex=300' \
-  -machine 'type=q35+pve0' \
+  -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0' \
+  -machine 'accel=tcg,type=pc+pve0' \
   -snapshot
diff --git a/test/cfg2cmd/simple1-template.conf.cmd b/test/cfg2cmd/simple1-template.conf.cmd
index a24151f8..e514446c 100644
--- a/test/cfg2cmd/simple1-template.conf.cmd
+++ b/test/cfg2cmd/simple1-template.conf.cmd
@@ -8,30 +8,26 @@
   -mon 'chardev=qmp-event,mode=control' \
   -pidfile /var/run/qemu-server/8006.pid \
   -daemonize \
-  -smbios 'type=1,uuid=7b10d7af-b932-4c66-b2c3-3996152ec465' \
-  -smp '3,sockets=1,cores=3,maxcpus=3' \
+  -smp '1,sockets=1,cores=1,maxcpus=1' \
   -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 768 \
+  -vga none \
+  -nographic \
+  -cpu qemu64 \
+  -m 512 \
   -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' \
   -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' \
-  -device 'vmgenid,guid=c773c261-d800-4348-9f5d-167fadd53cf8' \
   -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' \
   -device 'usb-tablet,id=tablet,bus=uhci.0,port=1' \
-  -device 'VGA,id=vga,bus=pci.0,addr=0x2' \
   -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
   -iscsi 'initiator-name=iqn.1993-08.org.debian:01:aabbccddeeff' \
   -drive 'if=none,id=drive-ide2,media=cdrom,aio=threads' \
   -device 'ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200' \
   -device 'virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5' \
   -drive 'file=/var/lib/vz/images/8006/base-8006-disk-1.qcow2,if=none,id=drive-scsi0,discard=on,format=qcow2,cache=none,aio=native,detect-zeroes=unmap,readonly=on' \
-  -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100' \
+  -device 'scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0' \
   -device 'ahci,id=ahci0,multifunction=on,bus=pci.0,addr=0x7' \
   -drive 'file=/var/lib/vz/images/8006/base-8006-disk-0.qcow2,if=none,id=drive-sata0,discard=on,format=qcow2,cache=none,aio=native,detect-zeroes=unmap' \
   -device 'ide-hd,bus=ahci0.0,drive=drive-sata0,id=sata0' \
-  -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=A2:C0:43:77:08:A0,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300' \
-  -machine 'type=pc' \
+  -machine 'accel=tcg,smm=off,type=pc' \
   -snapshot
-- 
2.39.2



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