[Libguestfs] [PATCH] Install VirtIO storage and network drivers in Windows

[Richard W.M. Jones]

On Mon, Aug 16, 2010 at 02:53:17PM +0100, Matthew Booth wrote:
> Currently when converting a Windows guest we do a minimum installation of the
> viostor driver, configure the RHEV guest agent and leave RHEV to properly
> install viostor and all remaining drivers. This works well if RHEV is properly
> configured and the installation is not interrupted on first boot.
> 
> However, if the target of the conversion is not RHEV, RHEV is not properly
> configured, or the first boot installation process is interrupted, for
> example by the user logging in and interacting with it, this will fail. In this
> case, in the absence of a correct driver Windows can mis-detect the VirtIO 'SCSI
> Controller' and configure the wrong driver for it. This will lead to the guest
> subsequently failing to boot.
> 
> This patch complements the RHEV-managed process by additionally copying
> installable versions of the VirtIO storage and network drivers to the guest
> during conversion, and adding the location of the drivers to the default search
> path for drivers. This means that Windows will install correct drivers for
> network and storage if the RHEV process fails, or if the conversion target is
> not RHEV.
> ---
>  lib/Sys/VirtV2V/Converter/Windows.pm |   77 ++++++++++++++++++++++++++++++++++
>  1 files changed, 77 insertions(+), 0 deletions(-)
> 
> diff --git a/lib/Sys/VirtV2V/Converter/Windows.pm b/lib/Sys/VirtV2V/Converter/Windows.pm
> index 1d4c526..f5bf399 100644
> --- a/lib/Sys/VirtV2V/Converter/Windows.pm
> +++ b/lib/Sys/VirtV2V/Converter/Windows.pm
> @@ -23,6 +23,7 @@ use warnings;
>  use Carp qw(carp);
>  use File::Temp qw(tempdir);
>  use Data::Dumper;
> +use Encode qw(encode decode);
>  use IO::String;
>  use XML::DOM;
>  use XML::DOM::XPath;
> @@ -187,6 +188,7 @@ sub _preconvert
>      _upload_files ($g, $tmpdir, $desc, $devices, $config);
>      _add_viostor_to_registry ($g, $tmpdir, $desc, $devices, $config);
>      _add_service_to_registry ($g, $tmpdir, $desc, $devices, $config);
> +    _prepare_virtio_drivers ($g, $tmpdir, $desc, $devices, $config);
>  }
>  
>  # See http://rwmj.wordpress.com/2010/04/30/tip-install-a-device-driver-in-a-windows-vm/
> @@ -345,6 +347,81 @@ sub _add_service_to_registry
>      $g->upload ($tmpdir . "/system", $system_filename);
>  }
>  
> +# We copy the VirtIO drivers to a directory on the guest and add this directory
> +# to HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\DevicePath so that it will
> +# be searched automatically when automatically installing drivers.
> +sub _prepare_virtio_drivers
> +{
> +    my $g = shift;
> +    my $tmpdir = shift;
> +    my $desc = shift;
> +    my $devices = shift;
> +    my $config = shift;
> +
> +    # Copy the target VirtIO drivers to the guest
> +    my $driverdir = File::Spec->catdir($g->case_sensitive_path("/windows"), "Drivers/VirtIO");
> +
> +    $g->mkdir_p($driverdir);
> +
> +    my ($virtio) = $config->match_app ($desc, 'virtio', $desc->{arch});
> +    $virtio = $config->get_transfer_path($g, $virtio);
> +
> +    foreach my $src ($g->ls($virtio)) {
> +        my $name = $src;
> +        $src = File::Spec->catfile($virtio);
> +        my $dst = File::Spec->catfile($driverdir, $name);
> +        $g->cp_a($src, $dst);
> +    }
> +
> +    # Locate and download the SOFTWARE hive
> +    my $sw_local = File::Spec->catfile($tmpdir, 'software');
> +    my $sw_guest = $g->case_sensitive_path('/windows/system32/config/software');
> +
> +    $g->download($sw_guest, $sw_local);
> +
> +    # Open the registry hive.
> +    my $h = Win::Hivex->open($sw_local, write => 1)
> +        or die "open hive $sw_local: $!";
> +
> +    # Find the node \Microsoft\Windows\CurrentVersion
> +    my $node = $h->root();
> +    foreach ('Microsoft', 'Windows', 'CurrentVersion') {
> +        $node = $h->node_get_child($node, $_);
> +    }
> +
> +    # Update DevicePath, but leave everything else as is
> +    my @new;
> +    my $append = ';%SystemRoot%\Drivers\VirtIO';
> +    foreach my $v ($h->node_values($node)) {
> +        my $key = $h->value_key($v);
> +        my ($type, $data) = $h->value_value($v);
> +
> +        # Decode the string from utf16le to perl native
> +        my $value = decode('UTF-16LE', $data);
> +
> +        # Append the driver location if it's not there already
> +        if ($key eq 'DevicePath' && index($value, $append) == -1) {
> +            # Remove the explicit trailing NULL
> +            chop($value);
> +
> +            # Append the new path and a new explicit trailing NULL
> +            $value .= $append."\0";
> +
> +            # Re-encode the string back to utf16le
> +            $data = encode('UTF-16LE', $value);
> +        }
> +
> +        push (@new, { key => $key, t => $type, value => $data });
> +    }
> +    $h->node_set_values($node, \@new);
> +
> +    $h->commit(undef);
> +    undef $h;
> +
> +    # Upload the new registry.
> +    $g->upload($sw_local, $sw_guest);
> +}
> +
>  sub _upload_files
>  {
>      my $g = shift;

As discussed on list, ACK.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/