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

[Hanweidong <hanweidong@xxxxxxxxxx>]

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

> 
> 
> >           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. 

--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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