[pve-devel] [PATCH v8 qemu-server 3/8] Include "-cpu" parameter with live-migration

[Fabian Ebner]

On 25.03.20 18:51, Thomas Lamprecht wrote:
> On 2/12/20 4:11 PM, Stefan Reiter wrote:
>> This is required to support custom CPU models, since the
>> "cpu-models.conf" file is not versioned, and can be changed while a VM
>> using a custom model is running. Changing the file in such a state can
>> lead to a different "-cpu" argument on the receiving side.
>>
>> This patch fixes this by passing the entire "-cpu" option (extracted
>> from /proc/.../cmdline) as a "qm start" parameter. Note that this is
>> only done if the VM to migrate is using a custom model (which we can
>> check just fine, since the <vmid>.conf *is* versioned with pending
>> changes), thus not breaking any live-migration directionality.
>>
>> Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
>> ---
>>
>> New in v6.
> 
> I get a merge conflict with this one. Could you please rebase the remaining
> patches on current master?	
> 
> Fabi, once Stefan got to sent the rebase, it would be great if you could take
> a look at this. Thanks!
> 
Ok.

>>
>>   PVE/API2/Qemu.pm            |  9 ++++++++-
>>   PVE/QemuMigrate.pm          | 22 ++++++++++++++++++++++
>>   PVE/QemuServer.pm           | 14 ++++++++++----
>>   PVE/QemuServer/CPUConfig.pm |  2 ++
>>   4 files changed, 42 insertions(+), 5 deletions(-)
>>
>> diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
>> index caca430..5ea6cf2 100644
>> --- a/PVE/API2/Qemu.pm
>> +++ b/PVE/API2/Qemu.pm
>> @@ -1986,6 +1986,11 @@ __PACKAGE__->register_method({
>>   		optional => 1,
>>   	    },
>>   	    machine => get_standard_option('pve-qemu-machine'),
>> +	    'force-cpu' => {
>> +		description => "Override QEMU's -cpu argument with the given string.",
>> +		type => 'string',
>> +		optional => 1,
>> +	    },
>>   	    targetstorage => {
>>   		description => "Target storage for the migration. (Can be '1' to use the same storage id as on the source node.)",
>>   		type => 'string',
>> @@ -2014,6 +2019,7 @@ __PACKAGE__->register_method({
>>   	my $timeout = extract_param($param, 'timeout');
>>   
>>   	my $machine = extract_param($param, 'machine');
>> +	my $force_cpu = extract_param($param, 'force-cpu');
>>   
>>   	my $get_root_param = sub {
>>   	    my $value = extract_param($param, $_[0]);
>> @@ -2066,7 +2072,8 @@ __PACKAGE__->register_method({
>>   		syslog('info', "start VM $vmid: $upid\n");
>>   
>>   		PVE::QemuServer::vm_start($storecfg, $vmid, $stateuri, $skiplock, $migratedfrom, undef, $machine,
>> -					  $spice_ticket, $migration_network, $migration_type, $targetstorage, $timeout);
>> +					  $spice_ticket, $migration_network, $migration_type, $targetstorage, $timeout,
>> +					  $force_cpu);
>>   		return;
>>   	    };
>>   
>> diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm
>> index 6db5e62..de27328 100644
>> --- a/PVE/QemuMigrate.pm
>> +++ b/PVE/QemuMigrate.pm
>> @@ -11,6 +11,8 @@ use PVE::Tools;
>>   use PVE::Cluster;
>>   use PVE::Storage;
>>   use PVE::QemuServer;
>> +use PVE::QemuServer::CPUConfig;
>> +use PVE::QemuServer::Helpers;
>>   use PVE::QemuServer::Machine;
>>   use PVE::QemuServer::Monitor qw(mon_cmd);
>>   use Time::HiRes qw( usleep );
>> @@ -219,7 +221,23 @@ sub prepare {
>>   
>>   	$self->{forcemachine} = PVE::QemuServer::Machine::qemu_machine_pxe($vmid, $conf);
>>   
>> +	# To support custom CPU types, we keep QEMU's "-cpu" parameter intact.
>> +	# Since the parameter itself contains no reference to a custom model,
>> +	# this makes migration independent of changes to "cpu-models.conf".
>> +	if ($conf->{cpu}) {
>> +	    my $cpuconf = PVE::QemuServer::CPUConfig::parse_cpu_conf_basic($conf->{cpu});
>> +	    if ($cpuconf && PVE::QemuServer::CPUConfig::is_custom_model($cpuconf->{cputype})) {
>> +		my $cmdline = PVE::QemuServer::Helpers::parse_cmdline($pid);
>> +		die "could not read commandline of running machine\n"
>> +		    if !$cmdline->{cpu}->{value};
>> +
>> +		# sanitize and untaint value
>> +		$cmdline->{cpu}->{value} =~ $PVE::QemuServer::CPUConfig::qemu_cmdline_cpu_re;
>> +		$self->{forcecpu} = $1;
>> +	    }
>> +	}
>>       }
>> +
>>       my $loc_res = PVE::QemuServer::check_local_resources($conf, 1);
>>       if (scalar @$loc_res) {
>>   	if ($self->{running} || !$self->{opts}->{force}) {
>> @@ -582,6 +600,10 @@ sub phase2 {
>>   	push @$cmd, '--machine', $self->{forcemachine};
>>       }
>>   
>> +    if ($self->{forcecpu}) {
>> +	push @$cmd, '--force-cpu', $self->{forcecpu};
>> +    }
>> +
>>       if ($self->{online_local_volumes}) {
>>   	push @$cmd, '--targetstorage', ($self->{opts}->{targetstorage} // '1');
>>       }
>> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
>> index f0c8abd..4252b68 100644
>> --- a/PVE/QemuServer.pm
>> +++ b/PVE/QemuServer.pm
>> @@ -3406,7 +3406,7 @@ sub query_understood_cpu_flags {
>>   }
>>   
>>   sub config_to_command {
>> -    my ($storecfg, $vmid, $conf, $defaults, $forcemachine) = @_;
>> +    my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $force_cpu) = @_;
>>   
>>       my $cmd = [];
>>       my $globalFlags = [];
>> @@ -3804,7 +3804,12 @@ sub config_to_command {
>>   	push @$rtcFlags, 'base=localtime';
>>       }
>>   
>> -    push @$cmd, get_cpu_options($conf, $arch, $kvm, $kvm_off, $machine_version, $winversion, $gpu_passthrough);
>> +    if ($force_cpu) {
>> +	push @$cmd, '-cpu', $force_cpu;
>> +    } else {
>> +	push @$cmd, get_cpu_options($conf, $arch, $kvm, $kvm_off,
>> +	    $machine_version, $winversion, $gpu_passthrough);
>> +    }
>>   
>>       PVE::QemuServer::Memory::config($conf, $vmid, $sockets, $cores, $defaults, $hotplug_features, $cmd);
>>   
>> @@ -5190,7 +5195,8 @@ sub vmconfig_update_disk {
>>   
>>   sub vm_start {
>>       my ($storecfg, $vmid, $statefile, $skiplock, $migratedfrom, $paused,
>> -	$forcemachine, $spice_ticket, $migration_network, $migration_type, $targetstorage, $timeout) = @_;
>> +	$forcemachine, $spice_ticket, $migration_network, $migration_type,
>> +	$targetstorage, $timeout, $force_cpu) = @_;
>>   
>>       PVE::QemuConfig->lock_config($vmid, sub {
>>   	my $conf = PVE::QemuConfig->load_config($vmid, $migratedfrom);
>> @@ -5279,7 +5285,7 @@ sub vm_start {
>>   	    print "Resuming suspended VM\n";
>>   	}
>>   
>> -	my ($cmd, $vollist, $spice_port) = config_to_command($storecfg, $vmid, $conf, $defaults, $forcemachine);
>> +	my ($cmd, $vollist, $spice_port) = config_to_command($storecfg, $vmid, $conf, $defaults, $forcemachine, $force_cpu);
>>   
>>   	my $migration_ip;
>>   	my $get_migration_ip = sub {
>> diff --git a/PVE/QemuServer/CPUConfig.pm b/PVE/QemuServer/CPUConfig.pm
>> index 65f0d76..315ef75 100644
>> --- a/PVE/QemuServer/CPUConfig.pm
>> +++ b/PVE/QemuServer/CPUConfig.pm
>> @@ -99,6 +99,8 @@ my @supported_cpu_flags = (
>>   my $cpu_flag_supported_re = qr/([+-])(@{[join('|', @supported_cpu_flags)]})/;
>>   my $cpu_flag_any_re = qr/([+-])([a-zA-Z0-9\-_\.]+)/;
>>   
>> +our $qemu_cmdline_cpu_re = qr/^((?>[+-]?[\w\-_=]+,?)+)$/;
>> +
>>   my $cpu_fmt = {
>>       cputype => {
>>   	description => "Emulated CPU type. Can be default or custom name (custom model names must be prefixed with 'custom-').",
>>
>