pci: add helpers to (un)reserve pciids for a vm

saves a list of pciid <-> vmid mappings in /var/run
that we can check when we start a vm

if we're not given a pid but a timeout, we save the time when the
reservation will run out (current time + timeout + 5s) since each
vm start (until we can save the pid) varies from config to config

reserve_pci_usage and remove_pci_reservation always expect a list of ids
so that we can update the reservation for a vm all at once

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>

diff --git a/PVE/QemuServer/PCI.pm b/PVE/QemuServer/PCI.pm
index 863e77e1d48efbb8ddad91ed4833e71b480dee0c..913d5fd207deb756907b29859259012768af164e 100644 (file)
--- a/PVE/QemuServer/PCI.pm
+++ b/PVE/QemuServer/PCI.pm
@@ -5,6 +5,7 @@ use strict;
 
 use PVE::JSONSchema;
 use PVE::SysFSTools;
+use PVE::Tools;
 
 use base 'Exporter';
 
@@ -484,4 +485,106 @@ sub prepare_pci_device {
     }
 }
 
+my $PCIID_RESERVATION_FILE = "/var/run/pve-reserved-pciids";
+my $PCIID_RESERVATION_LCK = "/var/lock/pve-reserved-pciids.lck";
+
+my $parse_pci_reservation = sub {
+    my $pciids = {};
+
+    if (my $fh = IO::File->new ($PCIID_RESERVATION_FILE, "r")) {
+       while (my $line = <$fh>) {
+           if ($line =~ m/^($PCIRE)\s(\d+)\s(time|pid)\:(\d+)$/) {
+               $pciids->{$1} = {
+                   vmid => $2,
+                   "$3" => $4,
+               };
+           }
+       }
+    }
+
+    return $pciids;
+};
+
+my $write_pci_reservation = sub {
+    my ($pciids) = @_;
+
+    my $data = "";
+    foreach my $p (keys %$pciids) {
+       my $entry = $pciids->{$p};
+       if (defined($entry->{pid})) {
+           $data .= "$p $entry->{vmid} pid:$entry->{pid}\n";
+       } else {
+           $data .= "$p $entry->{vmid} time:$entry->{time}\n";
+       }
+    }
+
+    PVE::Tools::file_set_contents($PCIID_RESERVATION_FILE, $data);
+};
+
+sub remove_pci_reservation {
+    my ($ids) = @_;
+
+    return if !scalar(@$ids); # do nothing for empty list
+
+    my $code = sub {
+       my $pciids = $parse_pci_reservation->();
+
+       for my $id (@$ids) {
+           delete $pciids->{$id};
+       }
+
+       $write_pci_reservation->($pciids);
+    };
+
+    PVE::Tools::lock_file($PCIID_RESERVATION_LCK, 10, $code);
+    die $@ if $@;
+
+    return;
+}
+
+sub reserve_pci_usage {
+    my ($ids, $vmid, $timeout, $pid) = @_;
+
+    return if !scalar(@$ids); # do nothing for empty list
+
+    PVE::Tools::lock_file($PCIID_RESERVATION_LCK, 10, sub {
+
+       my $ctime = time();
+       my $pciids = $parse_pci_reservation->();
+
+       for my $id (@$ids) {
+           my $errmsg = "PCI device '$id' already in use\n";
+           if (my $pciid = $pciids->{$id}) {
+               if ($pciid->{vmid} != $vmid) {
+                   # check time based reservation
+                   die $errmsg if defined($pciid->{time}) && $pciid->{time} > $ctime;
+
+                   # check running vm
+                   my $pid = PVE::QemuServer::Helpers::vm_running_locally($pciid->{vmid});
+                   if (my $oldpid = $pciid->{pid}) {
+                       die $errmsg if defined($pid) && $pid == $oldpid;
+                       warn "leftover PCI reservation found for $id, ignoring...\n"
+                           if !defined($pid) || $pid != $oldpid;
+                   }
+               }
+           }
+
+           $pciids->{$id} = {
+               vmid => $vmid,
+           };
+           if (defined($timeout)) {
+               # we save the time when the reservation gets invalid (+5s),
+               # since the start timeout depends on the config
+               $pciids->{$id}->{time} = $ctime + $timeout + 5;
+           }
+           $pciids->{$id}->{pid} = $pid if defined($pid);
+       }
+
+       $write_pci_reservation->($pciids);
+
+       return;
+    });
+    die $@ if $@;
+}
+
 1;