From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordan Bobic Subject: Re: vga passthrough with qemu-xen (or qemu upstream) Date: Mon, 20 Jan 2014 21:22:46 +0000 Message-ID: <52DD93A6.30100@bobich.net> References: <2fde37a507b3f97d79c6f65a203950b0@mail.shatteredsilicon.net> <0e1966027bab98420993970d931e7e92@mail.shatteredsilicon.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: "xen-devel@lists.xen.org" List-Id: xen-devel@lists.xenproject.org On 01/20/2014 09:15 PM, Shakeel Butt wrote: > On Mon, Jan 20, 2014 at 7:29 AM, Gordan Bobic wrote: >> On 2014-01-20 15:19, Shakeel Butt wrote: >>> >>> On Mon, Jan 20, 2014 at 5:31 AM, Gordan Bobic wrote: >>>> >>>> On 2014-01-20 13:24, Wu, Feng wrote: >>>>>> >>>>>> >>>>>> -----Original Message----- >>>>>> From: xen-devel-bounces@lists.xen.org >>>>>> [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of Gordan Bobic >>>>>> Sent: Monday, January 20, 2014 8:50 PM >>>>>> To: xen-devel@lists.xen.org >>>>>> Subject: Re: [Xen-devel] vga passthrough with qemu-xen (or qemu >>>>>> upstream) >>>>>> >>>>>> On 2014-01-20 12:31, Shakeel Butt wrote: >>>>>>> On Mon, Jan 20, 2014 at 4:09 AM, Stefano Stabellini >>>>>>> wrote: >>>>>>>> On Mon, 20 Jan 2014, Wu, Feng wrote: >>>>>>>>>> -----Original Message----- >>>>>>>>>> From: xen-devel-bounces@lists.xen.org >>>>>>>>>> [mailto:xen-devel-bounces@lists.xen.org] On Behalf Of Shakeel >>>>>>>>>> Butt >>>>>>>>>> Sent: Monday, January 20, 2014 1:48 PM >>>>>>>>>> To: xen-devel@lists.xen.org >>>>>>>>>> Subject: [Xen-devel] vga passthrough with qemu-xen (or qemu >>>>>>>>>> upstream) >>>>>>>>>> >>>>>>>>>> Hi all, >>>>>>>>>> >>>>>>>>>> Is it possible to do vga passthrough on xen-unstable with >>>>>>>>>> qemu-xen >>>>>>>>>> as >>>>>>>>>> device model? I tried but I am getting error 'gfx_passthru' >>>>>>>>>> invalid >>>>>>>>>> parameter for qemu-xen. I am able to do passthrough with qemu >>>>>>>>>> traditional i.e. qemu-dm. >>>>>>>>> >>>>>>>>> As far as I know, only qemu-traditional supports vga pass-through >>>>>>>>> right now. >>>>>>>> >>>>>>>> Right. >>>>>>>> It is not possible to assign your primary VGA card to a VM with >>>>>>>> qemu-xen. You should be able to assign your secondary VGA card >>>>>>>> though. >>>>>>> >>>>>>> Let me understand this correctly. If I have two VGA cards then I can >>>>>>> passthrough >>>>>>> secondary VGA card (in Dom0) to HVM as its primary VGA card. Is this >>>>>>> right and >>>>>>> if yes how can I do it? >>>>>> >>>>>> Passing any VGA card as a primary-in-domU has always been problematic. >>>>> >>>>> >>>>> >>>>> I think passing VGA card as a primary-in-domU works well in >>>>> Qemu-traditional, right? >>>> >>>> >>>> >>>> I never managed to get it working - it certainly isn't just a matter of >>>> enabling the option. There is at least the matter of also side-loading >>>> the VGA BIOS, and IIRC that was limited to 64KB in size, which rules >>>> out all ATI and Nvidia GPUs of the past 2-3 generations. >>>> >>>> Having said that - I never found a particularly good use-case for >>>> primary passthrough. Once the GPU driver loads it works just the >>>> same for all intents and purposes. >>>> >>> >>> I have successfully managed to passthrough VGA card as primary to DomU >>> with qemu traditional. I am trying to do the same with upstream qemu >>> because >>> I need some new features of the upstream qemu which are not available >>> in qemu traditional. >>> >>> With qemu upstream I can passthrough as secondary VGA card to DomU >>> and able to see it in device manager in DomU (Windows 7) but Windows >>> couldn't use it and display some error that another card is being used as >>> display. I want Windows to use the passthroughed vga card as its display. >> >> >> Disable the other (emulated) card in device manager and reboot >> the domU. That should fix it. > > This is not working for me. I am disabling the device and even uninstalling the > driver but on reboot Windows 7 install the driver for the emulated vga and > make it primary vga. Don't uninstall the driver, just disable the device. If you uninstall it, it will get re-detected. If you disable it, it should show up with a red cross next to it, and your secondary GPU will start working the way you want it to.