Re: [Xen-devel] GPU passthrough issue when VM is configured with 4G memory

[Pasi Kärkkäinen <pasik@xxxxxx>]

On Tue, Mar 05, 2013 at 12:44:36PM +0000, Hanweidong wrote:
> > 
> > >    I have tried to passthrough GPU card(Nvidia quadro 4000) on the latest
> > Xen
> > >    unstable version (QEMU is using Qemu-upsteam-unstable, not traditional
> > >    Qemu). This issue as below:
> > >
> > 
> > I don't think qemu-upstream has GPU/VGA passthrough support yet.
> 
> Qemu-upstream already supports GPU/VGA pass-through.
>

Really? With Xen? 
I haven't seen the patches.. 

> If we configure VM memory with 3G, GPU pass-through works well.
> 

Right..


> > 
> > 
> > >           Windows7 64-bit guest will blue screen when GPU passthrough
> > >    configure 4g memory,blue screen code is 50, and SUSE 11 64-bit guest
> > will
> > >    always stay at the grub screen.  I noticed that it will relocate RAM 
> > > that
> > >    overlaps PCI space in pci_setup()(tools/hvmloader/pci.c). If VM memory
> > is
> > >    configured with 3G, it won't cause relocate RAM that overlaps PCI space
> > in
> > >    pci_setup(), and GPU pass-through is no problem. So it seems this issue
> > is
> > >    related to "relocate RAM" in pci_setup().
> > >
> > >           In the failure case (VM memory is 4G), I used "memtest" to
> > check
> > >    memory of the VM which configured with more than 4G memory, the last
> > 256M
> > >    has errors.
> > >
> > >
> > >
> > >    BTW, Xen 4.1.2 doesn't have this issue.
> > >
> > 
> > I assume with Xen 4.1.2 you're using qemu-traditional.. ?
> 
>  Yes, we tried Xen 4.1.2 with qemu-traditional. 
> 
> > 
> > Try using qemu-traditional also with xen-unstable.
> > 
> 
> OK, we will have a try. But seems it's not qemu's problem, we can make GPU 
> pass-through succeed if we didn't do
> XENMAPSPACE_gmfn_range hypercall in pci_setup() with 4G memory. 
> 

Yep. Please send patches when you figure it out!


-- Pasi



> --Weidong
> 
> > -- Pasi
> > 
> > >
> > >
> > >    Any ideas about this issue? Thanks in advance.
> > >
> > >
> > 
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@xxxxxxxxxxxxx
> > > http://lists.xen.org/xen-devel
> 

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