Re: qemu-xen-dir + PCI passthrough = BOOM

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, Dec 05, 2013 at 12:16:32PM +0000, Anthony PERARD wrote:
> On Wed, Dec 04, 2013 at 02:51:48PM -0500, Konrad Rzeszutek Wilk wrote:
> > Hey,
> > 
> > I just started noticing it today - with qemu-xen (tip is
> > commit b97307ecaad98360f41ea36cd9674ef810c4f8cf
> >     xen_disk: mark ioreq as mapped before unmapping in error case)
> > 
> > when I try to pass in a PCI device at bootup it blows up with:
> > 
> > char device redirected to /dev/pts/2 (label serial0)
> > qemu: hardware error: xen: failed to populate ram at 40050000
> 
> There is a good chance that the issue is in QEMU.
> 
> By default, qemu-xen is not very verbose, so a
> #define XEN_PT_LOGGING_ENABLED
> can help identifying what is missing.
> 
> The error is reported by xen_ram_alloc(), so it might help to enable
> trace for it. It's easy:
> sh$ cat > /tmp/trace-to-enable << EOF
> xen_ram_alloc
> EOF
> 
> then
> device_model_args_hvm = [ '-trace', 'events=/tmp/trace-to-enable' ]
> 
> There is more of those trace events in qemu.git/trace-events

char device redirected to /dev/pts/2 (label serial0)
xen_ram_alloc requested: 0x3f800000, size 0x800000
xen_ram_alloc requested: 0x40000000, size 0x10000
xen_ram_alloc requested: 0x40010000, size 0x40000
[00:05.0] xen_pt_initfn: Assigning real physical device 01:00.0 to devfn
0x28
[00:05.0] xen_pt_register_regions: IO region 0 registered
(size=0x20000lx base_addr=0xfbc20000lx type: 0)
[00:05.0] xen_pt_register_regions: IO region 1 registered
(size=0x400000lx base_addr=0xfb800000lx type: 0)
[00:05.0] xen_pt_register_regions: IO region 2 registered (size=0x20lx
base_addr=0xe020lx type: 0x1)
[00:05.0] xen_pt_register_regions: IO region 3 registered (size=0x4000lx
base_addr=0xfbc44000lx type: 0)
xen_ram_alloc requested: 0x40050000, size 0x400000
qemu: hardware error: xen: failed to populate ram at 40050000

> 
> Does it works if you `xl pci-attach` after the guest has booted ?

-bash-4.1# xl pci-attach latest 01:00.0
libxl: error: libxl_qmp.c:448:qmp_next: Socket read error: Connection
reset by peer
-bash-4.1# head -16 /var/log/xen/qemu-dm-latest.log 
char device redirected to /dev/pts/3 (label serial0)
xen_ram_alloc requested: 0x3f800000, size 0x800000
xen_ram_alloc requested: 0x40000000, size 0x10000
xen_ram_alloc requested: 0x40010000, size 0x40000
xen be: vkbd-0: initialise() failed
xen be: vkbd-0: initialise() failed
xen be: vkbd-0: initialise() failed
[00:04.0] xen_pt_initfn: Assigning real physical device 01:00.0 to devfn
0x20
[00:04.0] xen_pt_register_regions: IO region 0 registered
(size=0x20000lx base_addr=0xfbc20000lx type: 0)
[00:04.0] xen_pt_register_regions: IO region 1 registered
(size=0x400000lx base_addr=0xfb800000lx type: 0)
[00:04.0] xen_pt_register_regions: IO region 2 registered (size=0x20lx
base_addr=0xe020lx type: 0x1)
[00:04.0] xen_pt_register_regions: IO region 3 registered (size=0x4000lx
base_addr=0xfbc44000lx type: 0)
xen_ram_alloc requested: 0x40010000, size 0x400000
qemu: hardware error: xen: failed to populate ram at 40010000
CPU #0:
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000633