Re: [Libguestfs] [PATCH] v2v: virtio-win: include *.dll too

On Sun, Nov 08, 2015 at 10:15:31AM +0200, Yan Vugenfirer wrote: > > > On 06 Nov 2015, at 08:51, Vadim Rozenfeld <vrozenfe(a)redhat.com&gt; wrote: > > > > On Thu, 2015-11-05 at 21:46 +0000, Richard W.M. Jones wrote: > >> On Thu, Oct 29, 2015 at 11:05:42AM +1100, Vadim Rozenfeld wrote: > >>> On Wed, 2015-10-28 at 14:53 +0300, Roman Kagan wrote: > >>>> 1) tell which devices can be configured > >>> Not sure that I fully understated your question. but if you are going to > >>> create some sort of off-line automatic virtio-win drivers update > >>> utility, then it shouldn't be too complicated. Firs of all you will need > >>> to obtain the Windows kernel version by reading the following Registry > >>> key - "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion". Let's say it > >>> 6.3, which means that it is Win8.1 or WS2012R2, parsing "BuildLabEx" > >>> string from the same hive will give you information about the platform > >>> bitness. Next you need to go through inf files, and find "DriverVer" > >>> string, like this one . taken from from vioscsi.inf > >>> > >>> DriverVer=08/01/2015,62.72.104.10800 > >>> > >>> This string contains build time and version stamps. The version stamp > >>> looks as follow "62.72.104.10800" > >>> where 62 means a target Windows kernel version multiplied by 10. In this > >>> case it is 6.2 which means Win8 or WS2012 > >>> 72 - the target host platform version multiplied bu 10 (was RHEL7.2) > >>> 104 just a magic number, but it can be changed, don't make any > >>> assumption based on this number. > >>> 10800 our internal build number (build 108) multiplied by 100 > >> > >> Hi Vadim, > >> > >> I've almost finished implementing this, but I have a couple of > >> technical questions: > >> > >> (1) How can we tell from the .inf file what architecture (x86 or > >> amd64) the driver is for? There is a [Manufacturer] section which > >> looks hopeful, eg: > >> > >> [Manufacturer] > >> %RHEL% = RHEL,NTAMD64 > >> > >> but the contents are not very consistent across all the .inf files I > >> have access to. > > > > Hi Richard, > > > > It should be consistent. We do specify target architecture (amd64 or > > x86) when stamping inf/inx files. IIRC, qemupciserial.inf is the only > > exception, but it goes without binaries. In any case, if you are going > > to use existing distribution media, you can rely on the media layout - > > for example, if "amd64" is a part of your current path - you are in > > 64-bit directory. > >> > >> (2) If we have a directory containing multiple drivers, can we assume > >> that if any .inf file found matches the guest OS, then all those > >> drivers can be installed? So far this appears to be true. > > Yes, we will never mix 32 and 64 bit drivers into the same directory. > > I swear:) > > > >> If not > >> then we have to start associating drivers with .inf files, which seems > >> a bit complicated. > >> > >> (3) You write: > >> > >>> If you found an inf file with the matching minor OS (6 in our case) > >>> version and matching or less but close minor version number (2 vs 3) > >>> then you are in the right directory. > >> > >> When you say "close minor version number" is there a particular > >> definition you have in mind? eg. minor or minor-1 is OK? Or do we > >> have to consider all .inf files in totality and choose the nearest > >> one? > > Ideally, we should try finding the exact match. If not, we have to find > > one with the same major version number and nearest minor number which is > > smaller than the target one. For example, let's say we are looking for a > > driver for Win8.1/WS2012R2, we know that both of them have kernel > > version 6.3 . So, ideally we should to find inf file with the following > > driver version string: > > > > DriverVer=XX/YY/ZZZZ,63.AA.BBB.CCCCC > > > > if we cannot find an inf file with such criteria, we should try finding > > another one with the OS version 62 (which means that a driver was build > > for kernel 6.2 Win8/WS2012 and technically should be compatible with > > 6.3). So, we are looking for DriverVer which looks like this one: > > DriverVer=XX/YY/ZZZZ,62.AA.BBB.CCCCC > > > > Still no luck - decrease the target OS version to 61 and repeat. > > > > For WDF drivers like balloon, vioserial, and rng you can go as far as > > you can trying to find an appropriate driver. > > > > For miniport drivers like netkvm ( Yan, please confirm ), viostor and > > vioscsi I wouldn't go too far. For example drivers designed to fork in > > specific stacks at kernel version 5.1 (WinXP) can refuse working with > > kernel 6.2 (Win8). > > While NDIS miniport designed for NDIS 5.1 (XP) still can run on latest Windows, I wouldn’t do that. For NDIS 6.x (Windows 2008 and newer), we can use older drivers on new OS. > But installing a driver for a newer OS on older OS might lead to driver miss-behaviour. I'm wondering how people who don't rely on virt-v2v are supposed to discover the virtio drivers for their guests? This includes both those who do it programmatically and those who locate the appropriate drivers manually. I mean, both manual and programmatic procedures should resolve to the same set of drivers, and ideally the procedure should be the same, declared official and documented. I see no problem implementing any particular algorithm, no matter how complex, in v2v, but I'd like to make sure that my colleagues who, say, write a tool for unattended deployment of Windows guests, or others, who manually set up their Windows VMs, arrive at the same configuration. I tend to think that your original idea of sorting that out on the driver build side, and storing the resulting drivers grouped by Windows arch/version following a well-defined and stable naming convention is a more reliable and universal solution.

Thanks, Roman.