From fc23c72a428a2cf2f3cee3df02801b5d65dd834e Mon Sep 17 00:00:00 2001
From: Dominik Csapak <d.csapak@proxmox.com>
Date: Tue, 6 Aug 2024 14:22:00 +0200
Subject: [PATCH] pci: device selection: don't reserve PCI IDs when VM is
 already running

Since the only way this could happen is when we're being called
from 'qm showcmd' and there we don't want to reserve or create anything.

In case the VM was not running, we actually reserve the devices, so we
want to call 'cleanup_pci_devices' after to remove those again. This
minimizes the timespan where those devices are not available for real vm
starts.

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Tested-by: Christoph Heiss <c.heiss@proxmox.com>
Reviewed-by: Christoph Heiss <c.heiss@proxmox.com>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
---
 PVE/QemuServer.pm                | 5 +++++
 PVE/QemuServer/PCI.pm            | 9 +++++++--
 test/run_config2command_tests.pl | 5 ++++-
 3 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 9117588b..9c20a7ce 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -6163,6 +6163,11 @@ sub vm_commandline {
     my $defaults = load_defaults();
 
     my $cmd = config_to_command($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu);
+    # if the vm is not running, we need to clean up the reserved/created devices
+    if (!PVE::QemuServer::Helpers::vm_running_locally($vmid)) {
+	eval { cleanup_pci_devices($vmid, $conf) };
+	warn $@ if $@;
+    }
 
     return PVE::Tools::cmd2string($cmd);
 }
diff --git a/PVE/QemuServer/PCI.pm b/PVE/QemuServer/PCI.pm
index 3b0da39d..3aa260d6 100644
--- a/PVE/QemuServer/PCI.pm
+++ b/PVE/QemuServer/PCI.pm
@@ -523,6 +523,9 @@ sub parse_hostpci_devices {
 my sub choose_hostpci_devices {
     my ($devices, $vmid) = @_;
 
+    # if the vm is running, we must be in 'showcmd', so don't actually reserve or create anything
+    my $is_running = PVE::QemuServer::Helpers::vm_running_locally($vmid) ? 1 : 0;
+
     my $used = {};
 
     my $add_used_device = sub {
@@ -555,8 +558,10 @@ my sub choose_hostpci_devices {
 	    my $ids = [map { $_->{id} } @$alternative];
 
 	    next if grep { defined($used->{$_}) } @$ids; # already used
-	    eval { reserve_pci_usage($ids, $vmid, 10, undef) };
-	    next if $@;
+	    if (!$is_running) {
+		eval { reserve_pci_usage($ids, $vmid, 10, undef) };
+		next if $@;
+	    }
 
 	    # found one that is not used or reserved
 	    $add_used_device->($alternative);
diff --git a/test/run_config2command_tests.pl b/test/run_config2command_tests.pl
index d48ef562..9b5e87ff 100755
--- a/test/run_config2command_tests.pl
+++ b/test/run_config2command_tests.pl
@@ -196,7 +196,10 @@ $qemu_server_module->mock(
     },
     get_initiator_name => sub {
 	return 'iqn.1993-08.org.debian:01:aabbccddeeff';
-    }
+    },
+    cleanup_pci_devices => {
+	# do nothing
+    },
 );
 
 my $qemu_server_config;