[pve-devel] [PATCH] Add patches for iothread_vq

[Dominik Budzowski]

---
 drive-iothread-vq-pve8.4.patch      |  33 ++++++++
 qemuserver-iothread-vq-pve8.4.patch | 123 ++++++++++++++++++++++++++++
 2 files changed, 156 insertions(+)
 create mode 100644 drive-iothread-vq-pve8.4.patch
 create mode 100644 qemuserver-iothread-vq-pve8.4.patch

diff --git a/drive-iothread-vq-pve8.4.patch b/drive-iothread-vq-pve8.4.patch
new file mode 100644
index 0000000..0fd39be
--- /dev/null
+++ b/drive-iothread-vq-pve8.4.patch
@@ -0,0 +1,33 @@
+--- Drive.pm	2025-06-09 18:31:45.482659331 +0200
++++ Drive.pm	2025-06-09 19:00:29.962125989 +0200
+@@ -275,6 +275,14 @@
+ 	optional => 1,
+ });
+ 
++my %iothread_vq_mapping_fmt = ( iothread_vq_mapping => {
++    type => 'integer',
++    description => "Whether to use iothread-vq-mapping for this drive",
++    minimum => 2,
++    maximum => 16,
++    optional => 1,
++});
++
+ my %product_fmt = (
+     product => {
+ 	type => 'string',
+@@ -442,6 +450,7 @@
+ my $virtio_fmt = {
+     %drivedesc_base,
+     %iothread_fmt,
++    %iothread_vq_mapping_fmt,
+     %readonly_fmt,
+ };
+ my $virtiodesc = {
+@@ -537,6 +546,7 @@
+ my $alldrive_fmt = {
+     %drivedesc_base,
+     %iothread_fmt,
++    %iothread_vq_mapping_fmt,
+     %model_fmt,
+     %product_fmt,
+     %queues_fmt,
diff --git a/qemuserver-iothread-vq-pve8.4.patch b/qemuserver-iothread-vq-pve8.4.patch
new file mode 100644
index 0000000..9719091
--- /dev/null
+++ b/qemuserver-iothread-vq-pve8.4.patch
@@ -0,0 +1,123 @@
+--- QemuServer.pm	2025-06-25 22:36:12.414594136 +0200
++++ QemuServer.pm	2025-06-25 23:22:38.522270102 +0200
+@@ -1301,17 +1301,79 @@
+     return "usb-kbd,id=keyboard,bus=ehci.0,port=2";
+ }
+ 
++# Helper to generate iothread/VQ mapping for block devices
++sub generate_iothread_vq_mapping {
++    my ($vmid, $drive) = @_;
++    my ($use_iothread_vq_mapping, $use_iothread, @vq_map);
++
++    if ($drive->{iothread_vq_mapping}) {
++        $use_iothread_vq_mapping = 1;
++        @vq_map = map { { iothread => "iothread-${vmid}-$_" } }
++                  0 .. $drive->{iothread_vq_mapping} - 1;
++    } elsif ($drive->{iothread}) {
++        $use_iothread = 1;
++    }
++
++    return ($use_iothread_vq_mapping, $use_iothread, \@vq_map);
++}
++
++# Main sub: JSON encoder for ordered key-value pairs and full drive device construction
+ sub print_drivedevice_full {
+     my ($storecfg, $conf, $vmid, $drive, $bridges, $arch, $machine_type) = @_;
+ 
+-    my $device = '';
+-    my $maxdev = 0;
+-
++    # Compute drive ID and PCI address for virtio
+     my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive);
++    my $pciaddr = '';
++    if ($drive->{interface} eq 'virtio') {
++        $pciaddr = print_pci_addr($drive_id, $bridges, $arch, $machine_type);
++    }
++
++    # Generate iothread/VQ mapping flags and mapping array
++    my ($use_iothread_vq_mapping, $use_iothread, $vq_map_ref) =
++        generate_iothread_vq_mapping($vmid, $drive);
++
++    # Prepare base JSON encoder
++    my $json = JSON->new->canonical(1);
++    my $device;
++
++    # Virtio interface handling
+     if ($drive->{interface} eq 'virtio') {
+-	my $pciaddr = print_pci_addr("$drive_id", $bridges, $arch, $machine_type);
+-	$device = "virtio-blk-pci,drive=drive-$drive_id,id=${drive_id}${pciaddr}";
+-	$device .= ",iothread=iothread-$drive_id" if $drive->{iothread};
++        if ($use_iothread_vq_mapping) {
++	    my ($bus, $addr) = ();
++	    if ($pciaddr =~ /^,bus=([^,]+),addr=(.+)$/) {
++    	    ($bus, $addr) = ($1, $2);
++	    }
++            my @fields = (
++                [ driver              => 'virtio-blk-pci'   ],
++                [ 'iothread-vq-mapping' => $vq_map_ref      ],
++                [ 'queue-size'        => 1024               ],
++                [ 'config-wce'        => JSON::false        ],
++                [ drive               => "drive-$drive_id"  ],
++                [ id                  => $drive_id          ],
++                [ bus                 => $bus               ],
++                [ addr                => $addr              ],
++                ($drive->{bootindex} ? [ bootindex => $drive->{bootindex} ] : ()),
++            );
++            my @parts;
++            for my $fld (@fields) {
++                my ($k, $v) = @$fld;
++                push @parts, $json->encode($k) . ':' . $json->encode($v);
++            }
++            $device = '{' . join(',', @parts) . '}';
++        }
++        elsif ($use_iothread) {
++            $device = sprintf(
++                'virtio-blk-pci,drive=drive-%s,id=%s%s,iothread=iothread-%s',
++                $drive_id, $drive_id, $pciaddr, $drive_id
++            );
++        }
++        else {
++            $device = sprintf(
++                'virtio-blk-pci,drive=drive-%s,id=%s%s',
++                $drive_id, $drive_id, $pciaddr
++            );
++        }
++
+     } elsif ($drive->{interface} eq 'scsi') {
+ 
+ 	my ($maxdev, $controller, $controller_prefix) = scsihw_infos($conf, $drive);
+@@ -1386,7 +1448,7 @@
+ 	die "unsupported interface type";
+     }
+ 
+-    $device .= ",bootindex=$drive->{bootindex}" if $drive->{bootindex};
++    $device .= ",bootindex=$drive->{bootindex}" if $drive->{bootindex} && !$use_iothread_vq_mapping;
+ 
+     if (my $serial = $drive->{serial}) {
+ 	$serial = URI::Escape::uri_unescape($serial);
+@@ -3911,8 +3973,23 @@
+ 
+ 	$drive->{bootindex} = $bootorder->{$ds} if $bootorder->{$ds};
+ 
+-	if ($drive->{interface} eq 'virtio'){
+-           push @$cmd, '-object', "iothread,id=iothread-$ds" if $drive->{iothread};
++#	if ($drive->{interface} eq 'virtio'){
++#           push @$cmd, '-object', "iothread,id=iothread-$ds" if $drive->{iothread};
++#	}
++
++	if ($drive->{interface} eq 'virtio') {
++
++	    if ($drive->{iothread_vq_mapping}) {
++
++		for my $i (0 .. $drive->{iothread_vq_mapping} - 1) {
++		    my $id = "iothread,id=iothread-$vmid-$i";
++		    push @$cmd, ('-object', $id) unless grep { $_ eq $id } @$cmd;
++		}
++	    } elsif ($drive->{iothread}) {
++
++		my $id = "iothread,id=iothread-$ds";
++		push @$cmd, ('-object', $id) unless grep { $_ eq $id } @$cmd;
++	    }
+ 	}
+ 
+ 	if ($drive->{interface} eq 'scsi') {
-- 
2.39.5