2014-05-28 18:41 GMT+02:00 Stefano Stabellini < stefano.stabell...@eu.citrix.com>:
> On Wed, 28 May 2014, Stefano Stabellini wrote: > > On Wed, 28 May 2014, Fabio Fantoni wrote: > > > Il 26/05/2014 10:00, Fabio Fantoni ha scritto: > > > > Il 25/05/2014 16:14, Stefano Stabellini ha scritto: > > > > > On Fri, 23 May 2014, Fabio Fantoni wrote: > > > > > > Il 23/05/2014 18:07, Stefano Stabellini ha scritto: > > > > > > > Choose pc-i440fx-1.6 instead of pc for HVM guests, so that we > know for > > > > > > > sure what is the machine that we are emulating. > > > > > > > > > > > > > > Use pc-i440fx-1.6 regardless of the xen_platform_pci option. > Add the > > > > > > > xen-platform device if requested. Choose slot 2 for the > xen-platform > > > > > > > device for compatibility with current installations. In case > of Intel > > > > > > > graphic passthrough, slot 2 might be needed by the grafic card. > > > > > > > However > > > > > > > now that we can specify the slot explicitly, it is easy to > change the > > > > > > > position of the xen-platform device on the PCI bus if graphic > > > > > > > passthrough is enabled. > > > > > > > > > > > > > > Move the machine options earlier, before any other emulated > devices > > > > > > > options. Otherwise the selected PCI slot for the xen-platform > device > > > > > > > is > > > > > > > not available in QEMU. > > > > > > > > > > > > > > Specify PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off, > because > > > > > > > differently from xenfv, the other QEMU machines do not have > that > > > > > > > option > > > > > > > off by default. > > > > > > > > > > > > > > This patch does not change the emulated environment in the > guest. > > > > > > > > > > > > > > Refer to this thread: > > > > > > > http://marc.info/?l=xen-devel&m=140023775929625&w=2 > > > > > > > > > > > > > > Signed-off-by: Stefano Stabellini < > stefano.stabell...@eu.citrix.com> > > > > > > > > > > > > > > diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c > > > > > > > index 8abed7b..fef684f 100644 > > > > > > > --- a/tools/libxl/libxl_dm.c > > > > > > > +++ b/tools/libxl/libxl_dm.c > > > > > > > @@ -476,6 +476,29 @@ static char ** > > > > > > > libxl__build_device_model_args_new(libxl__gc *gc, > > > > > > > flexarray_vappend(dm_args, "-k", keymap, NULL); > > > > > > > } > > > > > > > + flexarray_append(dm_args, "-machine"); > > > > > > > + switch (b_info->type) { > > > > > > > + case LIBXL_DOMAIN_TYPE_PV: > > > > > > > + flexarray_append(dm_args, "xenpv"); > > > > > > > + for (i = 0; b_info->extra_pv && b_info->extra_pv[i] > != NULL; > > > > > > > i++) > > > > > > > + flexarray_append(dm_args, b_info->extra_pv[i]); > > > > > > > + break; > > > > > > > + case LIBXL_DOMAIN_TYPE_HVM: > > > > > > > + flexarray_append(dm_args, "pc-i440fx-1.6,accel=xen"); > > > > > > > > I think that a note in README should be added: qemu >=1.6.1 is > required for > > > > hvm domUs. > > > > > > > > About the other xl parameter to be added I think that should be: > > > > qemu_machine_type="i440fx"|"q35" (when also q35 will be supported on > xen) > > > > qemu_machine_version="x.y" to specify the machine version, useful for > > > > debug/testing and other some cases. > > > > > > > > > > > + flexarray_append(dm_args, "-global"); > > > > > > > + flexarray_append(dm_args, > > > > > > > "PIIX4_PM.acpi-pci-hotplug-with-bridge-support=off"); > > > > > > I think is good add a comment for remember to remove this > workaround > > > > > > when pc > > > > > > > =2.1 will be the default since qemu 2.1 will fix it. > > > > > > > https://lists.gnu.org/archive/html/qemu-devel/2014-05/msg04789.html > > > > > The workaround is not actually harmful, it doesn't need to be > removed > > > > > when pc >= 2.1 in QEMU. > > > > > > > > > > > > > > > > > + if > (libxl_defbool_val(b_info->u.hvm.xen_platform_pci)) { > > > > > > > + flexarray_append(dm_args, "-device"); > > > > > > > + flexarray_append(dm_args, > "xen-platform,addr=0x2"); > > > > > > The fixed pci address to 0x2 probably is a problem with intel gpu > > > > > > passthrough: > > > > > > > http://lists.gnu.org/archive/html/qemu-devel/2014-05/msg03726.html > > > > > Right, however we cannot really change the default position of the > > > > > xen-platform device on the PCI bus, otherwise we'll end up > changing the > > > > > emulated environment for all the VMs out there. > > > > > > > > > > I'll leave it to Tiejun to move xen-platform to another slot when > > > > > graphic passthrough is enabled. > > > > > > > > > > I found another case of problem with xen-platform's fixed pci slot. > > > I tested this patch and I saw that qemu not start also in other cases, > for > > > example the domU of my test: > > > > qemu-system-i386: -device xen-platform,addr=0x2: PCI: slot 2 > function 0 not > > > > available for xen-platform, in use by intel-hda > > > > qemu-system-i386: -device xen-platform,addr=0x2: Device > initialization > > > > failed. > > > > qemu-system-i386: -device xen-platform,addr=0x2: Device > 'xen-platform' could > > > > not be initialized > > > > > > The domU's xl cfg: > > > > name='W7' > > > > builder="hvm" > > > > #device_model_override="/usr/lib/xen/bin/qemu-gdb" > > > > #device_model_override="/usr/bin/qemu-system-x86_64" > > > > #bios="ovmf" > > > > memory=2048 > > > > vcpus=2 > > > > #nestedhvm=1 > > > > #vif=['model=e1000,bridge=xenbr0'] > > > > vif=['bridge=xenbr0,mac=00:16:3e:42:ae:8f'] > > > > disk=['/mnt/vm/disks/W7.disk1.xm,raw,hda,rw',',raw,hdb,ro,cdrom'] > > > > boot='dc' > > > > device_model_version="qemu-xen" > > > > viridian=1 > > > > vnc=0 > > > > keymap="it" > > > > on_crash="destroy" > > > > vga="qxl" > > > > #videoram=64 > > > > spice=1 > > > > spicehost='0.0.0.0' > > > > spiceport=6002 > > > > spicedisable_ticketing=1 > > > > spicevdagent=1 > > > > spice_clipboard_sharing=0 > > > > spice_image_compression="off" > > > > spice_streaming_video="filter" > > > > spiceusbredirection=4 > > > > soundhw="hda" > > > > >From the error message, it looks like soundhw is the option that > > conflicts with xen-platform,addr=0x2. > > > > > > > > localtime=1 > > > > usbversion=2 > > > > > > Probably there are also other cases that can create a problem with > > > xen-platform fixed address, FWIK now new usb controller (with > usbversion) is > > > the only other with fixed pci address in libxl, all other emulated qemu > > > components not. > > > And call it before in qemu binary starts notaffect the pci slot order > because > > > the xen-platform is already before audio. > > > > Actually it looks like that by passing -device xen-platform before the > > other options, it already tries to assign slot 2 if possible. I don't > > need to specify addr=0x2. That seems to be the best course of action. > > However it would still place xen-platform at slot 3 instead of slot 2 if > soundhw is specified. It seems to me that there is not a perfect > solution to this problem. We can either: > > - Switch to -machine pc-i440fx-1.6 by default and use consistently the > same -machine option no matter the value of xen_platform_pci. Nice, but > we break compatibility with existing guests if soundhw is specified. > > - Switch to -machine pc-i440fx-1.6 only when xen_platform_pci=0 is > specified and keep xenfv if xen_platform_pci=1. We still break > compatibility when soundhw is specified together with xen_platform_pci=0. > FWIK removing the xen-platform's fixed pci slot will keep compatibility in any cases, assigning slots as it did before. I'll try tomorrow. Otherwise I think there would be problems in other cases, not only audio case. Perhaps even with save/restore/migrate.
