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add ivshmem device to config

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with such a shared memory device, a vm can share data with other
vms or with the host via memory

one of the use cases is looking-glass[1] with pci-passthrough, which copies
the guest fb to the host and you get a high-speed, low-latency
display client for the vm

on vm stop we delete the file again

1: https://looking-glass.hostfission.com/

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
This commit is contained in:
Dominik Csapak 2019-02-22 11:38:33 +01:00 committed by Thomas Lamprecht
parent e741c51696
commit 6dbcb07367
2 changed files with 48 additions and 0 deletions
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46
PVE/QemuServer.pm
View File

@ -256,6 +256,21 @@ my $vga_fmt = {
},
};
my $ivshmem_fmt = {
size => {
type => 'integer',
minimum => 1,
description => "The size of the file in MB.",
},
name => {
type => 'string',
pattern => '[a-zA-Z0-9\-]+',
optional => 1,
format_description => 'string',
description => "The name of the file. Will be prefixed with 'pve-shm-'. Default is the VMID. Will be deleted when the VM is stopped.",
},
};
my $confdesc = {
onboot => {
optional => 1,
@ -621,6 +636,12 @@ EODESCR
optional => 1,
description => "Script that will be executed during various steps in the vms lifetime.",
},
ivshmem => {
type => 'string',
format => $ivshmem_fmt,
description => "Inter-VM shared memory. Useful for direct communication between VMs, or to the host.",
optional => 1,
}
};
my $confdesc_cloudinit = {
@ -2808,6 +2829,8 @@ sub check_local_resources {
$loc_res = 1 if $conf->{hostusb}; # old syntax
$loc_res = 1 if $conf->{hostpci}; # old syntax
$loc_res = 1 if $conf->{ivshmem};
foreach my $k (keys %$conf) {
next if $k =~ m/^usb/ && ($conf->{$k} eq 'spice');
# sockets are safe: they will recreated be on the target side post-migrate
@ -3908,6 +3931,24 @@ sub config_to_command {
push @$devices, '-device', $netdevicefull;
}
if ($conf->{ivshmem}) {
my $ivshmem = PVE::JSONSchema::parse_property_string($ivshmem_fmt, $conf->{ivshmem});
my $bus;
if ($q35) {
$bus = print_pcie_addr("ivshmem");
} else {
$bus = print_pci_addr("ivshmem", $bridges, $arch, $machine_type);
}
my $path = '/dev/shm/pve-shm-';
if ($ivshmem->{name}) {
$path .= $ivshmem->{name};
} else {
$path .= $vmid;
}
push @$devices, '-device', "ivshmem-plain,memdev=ivshmem$bus,";
push @$devices, '-object', "memory-backend-file,id=ivshmem,share=on,mem-path=$path,size=$ivshmem->{size}M";
}
if (!$q35) {
# add pci bridges
if (qemu_machine_feature_enabled ($machine_type, $kvmver, 2, 3)) {
@ -5464,6 +5505,11 @@ sub vm_stop_cleanup {
unlink "/var/run/qemu-server/${vmid}.$ext";
}
if ($conf->{ivshmem}) {
my $ivshmem = PVE::JSONSchema::parse_property_string($ivshmem_fmt, $conf->{ivshmem});
unlink '/dev/shm/pve-shm-' . ($ivshmem->{name} // $vmid);
}
foreach my $key (keys %$conf) {
next if $key !~ m/^hostpci(\d+)$/;
my $hostpciindex = $1;

2
PVE/QemuServer/PCI.pm
View File

@ -78,6 +78,7 @@ my $devices = {
'virtio13' => { bus => 2, addr => 8 },
'virtio14' => { bus => 2, addr => 9 },
'virtio15' => { bus => 2, addr => 10 },
'ivshmem' => { bus => 2, addr => 11 },
'virtioscsi0' => { bus => 3, addr => 1 },
'virtioscsi1' => { bus => 3, addr => 2 },
'virtioscsi2' => { bus => 3, addr => 3 },
@ -150,6 +151,7 @@ sub print_pcie_addr {
hostpci1bus0 => { bus => "pcie.0", addr => 17 },
hostpci2bus0 => { bus => "pcie.0", addr => 18 },
hostpci3bus0 => { bus => "pcie.0", addr => 19 },
ivshmem => { bus => 'pcie.0', addr => 20 },
};
if (defined($devices->{$id}->{bus}) && defined($devices->{$id}->{addr})) {