Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling

[Cornelia Huck <cohuck@redhat.com>]

On Tue, 8 Aug 2017 11:29:50 +0200
Thomas Huth <thuth@redhat.com> wrote:

> On 08.08.2017 11:15, Cornelia Huck wrote:
> > On Fri, 4 Aug 2017 16:59:34 +0200
> > Cornelia Huck <cohuck@redhat.com> wrote:
> >   
> >> On Fri,  4 Aug 2017 13:29:37 +0200
> >> Cornelia Huck <cohuck@redhat.com> wrote:
> >>  
> >>> Next version, not so many changes from v3.
> >>>
> >>> As you might have guessed, the goals are still the same:
> >>> - Being able to disable PCI support in a build completely.
> >>> - Properly fencing off PCI if the relevant facility bit is not provided.
> >>>
> >>> Changes v3->v4:
> >>> - introduce pci_available boolean
> >>> - use pci_available to fence off setting the zcpi facility bit
> >>> - collected tags
> >>>
> >>> Branch is still git://github.com/cohuck/qemu no-zpci-cpumodel    
> >>
> >> make check on a build with pci disabled revealed an interesting
> >> inconsistency: We create a virtio-9p-ccw device, but the base
> >> virtio-9p-device is in code that is not built for !pci.
> >>
> >> If I remove the pci dependency for hw/9pfs/ and fsdev/, things look
> >> fine (at least on s390x). We probably need a different dependency,
> >> though.
> >>
> >> virtio-9p maintainers, any suggestions?  
> > 
> > I have the patch below, which is ugly, but seems to work for me. Better
> > ideas welcome :)  
> 
> I haven't tried whether it works, but you could maybe change the define
> of CONFIG_VIRTFS instead:
> 
> diff --git a/configure b/configure
> index dd73cce..64d21f6 100755
> --- a/configure
> +++ b/configure
> @@ -5771,7 +5771,7 @@ if test "$libattr" = "yes" ; then
>    echo "CONFIG_LIBATTR=y" >> $config_host_mak
>  fi
>  if test "$virtfs" = "yes" ; then
> -  echo "CONFIG_VIRTFS=y" >> $config_host_mak
> +  echo 'CONFIG_VIRTFS=$(call lor, $(CONFIG_VIRTIO_PCI),$(CONFIG_VIRTIO_CCW)' >> $config_host_mak
>  fi
>  if test "$vhost_scsi" = "yes" ; then
>    echo "CONFIG_VHOST_SCSI=y" >> $config_host_mak
> 
> ... I think that should simplify the other statements quite a bit since
> you then only have to test CONFIG_VIRTFS in the other locations?
> 
>  Thomas

Would be a simplification if it worked, yes; not sure whether we should
change the semantic of --enable-virtfs to error out if we don't have
either virtio-pci or virtio-ccw?

> 
> 
> > From 0ba6427e7ac7cef38b487d28c9dce653d8cb9a71 Mon Sep 17 00:00:00 2001
> > From: Cornelia Huck <cohuck@redhat.com>
> > Date: Tue, 8 Aug 2017 11:03:38 +0200
> > Subject: [PATCH] 9pfs: fix dependencies
> > 
> > Nothing in fsdev/ or hw/9pfs/ depends on pci; it should rather depend
> > on CONFIG_VIRTFS and on the presence of an appropriate virtio transport
> > device.
> > 
> > Let's introduce CONFIG_VIRTIO_CCW to cover s390x and check for
> > CONFIG_VIRTFS && (CONFIG_VIRTIO_PCI || CONFIG_VIRTIO_CCW).
> > 
> > Signed-off-by: Cornelia Huck <cohuck@redhat.com>
> > ---
> >  default-configs/s390x-softmmu.mak | 1 +
> >  fsdev/Makefile.objs               | 9 +++------
> >  hw/Makefile.objs                  | 2 +-
> >  3 files changed, 5 insertions(+), 7 deletions(-)
> > 
> > diff --git a/default-configs/s390x-softmmu.mak b/default-configs/s390x-softmmu.mak
> > index 6ab2bc65ac..7f15ab68b1 100644
> > --- a/default-configs/s390x-softmmu.mak
> > +++ b/default-configs/s390x-softmmu.mak
> > @@ -8,3 +8,4 @@ CONFIG_S390_FLIC=y
> >  CONFIG_S390_FLIC_KVM=$(CONFIG_KVM)
> >  CONFIG_VFIO_CCW=$(CONFIG_LINUX)
> >  CONFIG_WDT_DIAG288=y
> > +CONFIG_VIRTIO_CCW=y
> > diff --git a/fsdev/Makefile.objs b/fsdev/Makefile.objs
> > index 659df6e187..10d8caa291 100644
> > --- a/fsdev/Makefile.objs
> > +++ b/fsdev/Makefile.objs
> > @@ -1,10 +1,7 @@
> > -ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)
> >  # Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.
> > -# only pull in the actual virtio-9p device if we also enabled virtio.
> > -common-obj-y = qemu-fsdev.o 9p-marshal.o 9p-iov-marshal.o
> > -else
> > -common-obj-y = qemu-fsdev-dummy.o
> > -endif
> > +# only pull in the actual virtio-9p device if we also enabled a virtio backend.
> > +common-obj-$(call land, $(CONFIG_VIRTFS),$(call lor, $(CONFIG_VIRTIO_PCI),$(CONFIG_VIRTIO_CCW)))= qemu-fsdev.o 9p-marshal.o 9p-iov-marshal.o
> > +common-obj-$(call lnot, $(call land, $(CONFIG_VIRTFS),$(call lor, $(CONFIG_VIRTIO_PCI),$(CONFIG_VIRTIO_CCW)))) = qemu-fsdev-dummy.o
> >  common-obj-y += qemu-fsdev-opts.o qemu-fsdev-throttle.o
> >  
> >  # Toplevel always builds this; targets without virtio will put it in
> > diff --git a/hw/Makefile.objs b/hw/Makefile.objs
> > index a2c61f6b09..10942fe0b4 100644
> > --- a/hw/Makefile.objs
> > +++ b/hw/Makefile.objs
> > @@ -1,4 +1,4 @@
> > -devices-dirs-$(call land, $(CONFIG_VIRTIO),$(call land,$(CONFIG_VIRTFS),$(CONFIG_PCI))) += 9pfs/
> > +devices-dirs-$(call land, $(CONFIG_VIRTFS),$(call lor,$(CONFIG_VIRTIO_PCI),$(CONFIG_VIRTIO_CCW))) += 9pfs/
> >  devices-dirs-$(CONFIG_SOFTMMU) += acpi/
> >  devices-dirs-$(CONFIG_SOFTMMU) += adc/
> >  devices-dirs-$(CONFIG_SOFTMMU) += audio/
> >   
>