[pve-devel] [PATCH v7 qemu-server 10/10] Include "-cpu" parameter with snapshots/suspend

[Stefan Reiter]

Just like with live-migration, custom CPU models might change after a
snapshot has been taken (or a VM suspended), which would lead to a
different QEMU invocation on rollback/resume.

Save the "-cpu" argument as a new "runningcpu" option into the VM conf
akin to "runningmachine" and use as override during rollback/resume.

No functional change with non-custom CPU types intended.

Signed-off-by: Stefan Reiter <s.reiter at proxmox.com>
---

New in v7.

 PVE/API2/Qemu.pm  |  1 +
 PVE/QemuConfig.pm | 36 +++++++++++++++++++++++++++---------
 PVE/QemuServer.pm | 28 ++++++++++++++++++++--------
 3 files changed, 48 insertions(+), 17 deletions(-)

diff --git a/PVE/API2/Qemu.pm b/PVE/API2/Qemu.pm
index f0b9e58..c2f6513 100644
--- a/PVE/API2/Qemu.pm
+++ b/PVE/API2/Qemu.pm
@@ -1098,6 +1098,7 @@ my $update_vm_api  = sub {
 		push @delete, 'lock'; # this is the real deal to write it out
 	    }
 	    push @delete, 'runningmachine' if $conf->{runningmachine};
+	    push @delete, 'runningcpu' if $conf->{runningcpu};
 	}
 
 	PVE::QemuConfig->check_lock($conf) if !$skiplock;
diff --git a/PVE/QemuConfig.pm b/PVE/QemuConfig.pm
index 1ba728a..852c309 100644
--- a/PVE/QemuConfig.pm
+++ b/PVE/QemuConfig.pm
@@ -5,9 +5,10 @@ use warnings;
 
 use PVE::AbstractConfig;
 use PVE::INotify;
+use PVE::QemuServer;
+use PVE::QemuServer::CPUConfig;
 use PVE::QemuServer::Helpers;
 use PVE::QemuServer::Monitor qw(mon_cmd);
-use PVE::QemuServer;
 use PVE::QemuServer::Machine;
 use PVE::Storage;
 use PVE::Tools;
@@ -156,15 +157,26 @@ sub __snapshot_save_vmstate {
     my $statefile = PVE::Storage::vdisk_alloc($storecfg, $target, $vmid, 'raw', $name, $size*1024);
     my $runningmachine = PVE::QemuServer::Machine::get_current_qemu_machine($vmid);
 
-    if ($suspend) {
-	$conf->{vmstate} = $statefile;
-	$conf->{runningmachine} = $runningmachine;
-    } else {
-	my $snap = $conf->{snapshots}->{$snapname};
-	$snap->{vmstate} = $statefile;
-	$snap->{runningmachine} = $runningmachine;
+    # get current QEMU -cpu argument
+    my $runningcpu;
+    if (my $pid = PVE::QemuServer::check_running($vmid)) {
+	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;
+	$runningcpu = $1;
     }
 
+    if (!$suspend) {
+	$conf = $conf->{snapshots}->{$snapname};
+    }
+
+    $conf->{vmstate} = $statefile;
+    $conf->{runningmachine} = $runningmachine;
+    $conf->{runningcpu} = $runningcpu;
+
     return $statefile;
 }
 
@@ -310,6 +322,11 @@ sub __snapshot_rollback_hook {
 	if (defined($conf->{runningmachine})) {
 	    $data->{forcemachine} = $conf->{runningmachine};
 	    delete $conf->{runningmachine};
+
+	    # runningcpu is newer than runningmachine, so assume it only exists
+	    # here, if at all
+	    $data->{forcecpu} = delete $conf->{runningcpu}
+		if defined($conf->{runningcpu});
 	} else {
 	    # Note: old code did not store 'machine', so we try to be smart
 	    # and guess the snapshot was generated with kvm 1.4 (pc-i440fx-1.4).
@@ -362,7 +379,8 @@ sub __snapshot_rollback_vm_start {
     my ($class, $vmid, $vmstate, $data) = @_;
 
     my $storecfg = PVE::Storage::config();
-    PVE::QemuServer::vm_start($storecfg, $vmid, $vmstate, undef, undef, undef, $data->{forcemachine});
+    PVE::QemuServer::vm_start($storecfg, $vmid, $vmstate, undef, undef, undef,
+	$data->{forcemachine}, undef, undef, undef, undef, undef, $data->{forcecpu});
 }
 
 sub __snapshot_rollback_get_unused {
diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 4a5dfac..d7b9c09 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -532,8 +532,15 @@ EODESCR
 	optional => 1,
     }),
     runningmachine => get_standard_option('pve-qemu-machine', {
-	description => "Specifies the Qemu machine type of the running vm. This is used internally for snapshots.",
+	description => "Specifies the QEMU machine type of the running vm. This is used internally for snapshots.",
     }),
+    runningcpu => {
+	description => "Specifies the QEMU '-cpu' parameter of the running vm. This is used internally for snapshots.",
+	optional => 1,
+	type => 'string',
+	pattern => $PVE::QemuServer::CPUConfig::qemu_cmdline_cpu_re,
+	format_description => 'QEMU -cpu parameter'
+    },
     machine => get_standard_option('pve-qemu-machine'),
     arch => {
 	description => "Virtual processor architecture. Defaults to the host.",
@@ -2364,7 +2371,8 @@ sub json_config_properties {
     my $prop = shift;
 
     foreach my $opt (keys %$confdesc) {
-	next if $opt eq 'parent' || $opt eq 'snaptime' || $opt eq 'vmstate' || $opt eq 'runningmachine';
+	next if $opt eq 'parent' || $opt eq 'snaptime' || $opt eq 'vmstate' ||
+	    $opt eq 'runningmachine' || $opt eq 'runningcpu';
 	$prop->{$opt} = $confdesc->{$opt};
     }
 
@@ -5231,8 +5239,9 @@ sub vm_start {
 	PVE::GuestHelpers::exec_hookscript($conf, $vmid, 'pre-start', 1);
 
 	if ($is_suspended) {
-	    # enforce machine type on suspended vm to ensure HW compatibility
+	    # enforce machine type and CPU on suspended vm to ensure HW compatibility
 	    $forcemachine = $conf->{runningmachine};
+	    $force_cpu = $conf->{runningcpu};
 	    print "Resuming suspended VM\n";
 	}
 
@@ -5478,7 +5487,7 @@ sub vm_start {
 		PVE::Storage::deactivate_volumes($storecfg, [$vmstate]);
 		PVE::Storage::vdisk_free($storecfg, $vmstate);
 	    }
-	    delete $conf->@{qw(lock vmstate runningmachine)};
+	    delete $conf->@{qw(lock vmstate runningmachine runningcpu)};
 	    PVE::QemuConfig->write_config($vmid, $conf);
 	}
 
@@ -5491,13 +5500,15 @@ sub vm_commandline {
 
     my $conf = PVE::QemuConfig->load_config($vmid);
     my $forcemachine;
+    my $forcecpu;
 
     if ($snapname) {
 	my $snapshot = $conf->{snapshots}->{$snapname};
 	die "snapshot '$snapname' does not exist\n" if !defined($snapshot);
 
-	# check for a 'runningmachine' in snapshot
-	$forcemachine = $snapshot->{runningmachine} if $snapshot->{runningmachine};
+	# check for machine or CPU overrides in snapshot
+	$forcemachine = $snapshot->{runningmachine};
+	$forcecpu = $snapshot->{runningcpu};
 
 	$snapshot->{digest} = $conf->{digest}; # keep file digest for API
 
@@ -5506,7 +5517,8 @@ sub vm_commandline {
 
     my $defaults = load_defaults();
 
-    my $cmd = config_to_command($storecfg, $vmid, $conf, $defaults, $forcemachine);
+    my $cmd = config_to_command($storecfg, $vmid, $conf, $defaults,
+	$forcemachine, $forcecpu);
 
     return PVE::Tools::cmd2string($cmd);
 }
@@ -5780,7 +5792,7 @@ sub vm_suspend {
 		    mon_cmd($vmid, "savevm-end");
 		    PVE::Storage::deactivate_volumes($storecfg, [$vmstate]);
 		    PVE::Storage::vdisk_free($storecfg, $vmstate);
-		    delete $conf->@{qw(vmstate runningmachine)};
+		    delete $conf->@{qw(vmstate runningmachine runningcpu)};
 		    PVE::QemuConfig->write_config($vmid, $conf);
 		};
 		warn $@ if $@;
-- 
2.20.1