[Libguestfs] [V2V PATCH 1/1] convert_windows: add firstboot script to install drivers with pnputil

[Laszlo Ersek]

On 3/9/23 14:48, Richard W.M. Jones wrote:
> On Thu, Mar 09, 2023 at 03:47:10PM +0200, Andrey Drobyshev wrote:
>> On 3/8/23 22:52, Richard W.M. Jones wrote:
>>> On Wed, Mar 08, 2023 at 08:05:35PM +0200, Andrey Drobyshev wrote:
>>>> During conversion we copy the necessary drivers to the directory
>>>> "%systemroot%\Drivers\Virtio", adding it to the DevicePath registry
>>>> value.  As documented in [1], this should be enough for Windows to find
>>>> device drivers and successfully install them.
>>>>
>>>> However, it doesn't always happen.  Commit 73e009c04 ("v2v: windows:
>>>> Document use of pnputil to install drivers.") describes such issues with
>>>> Win2k12R2.  I'm seeing the same problem with Win2k16 and netkvm.sys
>>>> driver not being installed.
>>>>
>>>> That same commit 73e009c04 suggests adding a firstboot script invoking
>>>> pnputil at an early stage to install all the drivers we put into the
>>>> drivers store.  So let's add such a script to make sure all the
>>>> necessary drivers are installed.
>>>>
>>>> [1] https://learn.microsoft.com/en-us/windows-hardware/drivers/install/how-windows-selects-a-driver-for-a-device
>>>>
>>>> Signed-off-by: Andrey Drobyshev <andrey.drobyshev at virtuozzo.com>
>>>> ---
>>>>  convert/convert_windows.ml | 16 ++++++++++++++--
>>>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/convert/convert_windows.ml b/convert/convert_windows.ml
>>>> index 6bc2343b..e15a5e62 100644
>>>> --- a/convert/convert_windows.ml
>>>> +++ b/convert/convert_windows.ml
>>>> @@ -295,9 +295,11 @@ let convert (g : G.guestfs) _ inspect i_firmware block_driver _ static_ips =
>>>>      | Virt -> Virt
>>>>  
>>>>    and configure_firstboot () =
>>>> -    (* Note that pnp_wait.exe must be the first firstboot script as it
>>>> -     * suppresses PnP for all following scripts.
>>>> +    (* Run the firstboot script with pnputil.exe before the one with
>>>> +     * pnp_wait.exe as the latter suppresses PnP for all following scripts.
>>>>       *)
>>>> +    configure_pnputil_install ();
>>>> +
>>>>      let tool_path = virt_tools_data_dir () // "pnp_wait.exe" in
>>>>      if Sys.file_exists tool_path then
>>>>        configure_wait_pnp tool_path
>>>> @@ -345,6 +347,16 @@ let convert (g : G.guestfs) _ inspect i_firmware block_driver _ static_ips =
>>>>                        strkey name value
>>>>      | None -> sprintf "reg delete \"%s\" /v %s /f" strkey name
>>>>  
>>>> +  and configure_pnputil_install () =
>>>> +    let fb_script = "@echo off\n\
>>>> +                     \n\
>>>> +                     echo Wait for VirtIO drivers to be installed\n\
>>>> +                     %systemroot%\\Sysnative\\PnPutil -i -a \
>>>> +                     %systemroot%\\Drivers\\Virtio\\*.inf >\"%~dpn0.log\" 2>&1\
>>>> +                    " in
>>>> +    Firstboot.add_firstboot_script g inspect.i_root
>>>> +      "pnputil install drivers" fb_script;
>>>> +
>>>
>>> I'm not sure I'm really qualified to comment on this, since Windows is
>>> crazy.  I guess the worst this can do is fail to run, but that won't
>>> stop anything else from happening.
>>>
>>> Note that firstboot scripts already do logging, so I don't believe
>>> writing to a separate log file is needed here.  All the output from
>>> all firstboot scripts should go to
>>> C:\Program Files\Guestfs\Firstboot\log.txt:
>>>
>>> https://github.com/libguestfs/libguestfs-common/blob/7acf991a25b3fd625eb1ff1fbd8dc9fedf245942/mlcustomize/firstboot.ml#L276
>>
>> Right, but apart from having the log common for all firstboot scripts,
>> some of them also utilise separate log files in scripts-done directory,
>> e.g.:
>>
>> https://github.com/libguestfs/virt-v2v/blob/cb792fef27f/convert/convert_windows.ml#L381
>> https://github.com/libguestfs/virt-v2v/blob/cb792fef27f/convert/convert_windows.ml#L168
>>
>> So I did the same considering that pnputil's output is relatively long.
> 
> I think I'd probably get rid of those other scripts too.  It's helpful
> to have everything go to one place.  I'm not actually sure where those
> extra files end up.
> 
>> All in all, if there're no other concerns, can we give this script a go?
> 
> I think the patch is generally fine, so I'm just quibbling about
> the logging.

I'm surprised by this patch (which doesn't say much of course, because I
know precious little about Windows). What I'm noticing is "run
pnputil.exe before pnp_wait.exe before everything else".

We do queue a script earlier than those, at priority 2500, called
"v2vnetcf.ps1". See configure_network_interfaces ->
add_firstboot_powershell, and the reference to RHBZ 1788823.

And that script is exactly what tends *not* to work, and we've been
unable to get to the bottom of that issue. (See also RH 2068361 and
1963032.)

So... This patch could be orthogonal to that pre-existent symptom... but
could the patch perhaps *fix* the prior symptom? Is it possible that, if
we "forcibly install" the virtio drivers first, and *then* try to
configure IP addresses for the virtio-net NICs, then the latter will
start working reliably?

I have no idea really.

Anyway, once Rich is happy with the logging here, I have nothing against
the patch.

Acked-by: Laszlo Ersek <lersek at redhat.com>