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

Cornelia Huck posted 9 patches 6 years, 8 months ago
Failed in applying to current master (apply log)
accel/kvm/kvm-all.c               |  6 ++--
default-configs/s390x-softmmu.mak |  2 +-
hw/pci/pci-stub.c                 | 13 +++++++
hw/pci/pci.c                      |  2 ++
hw/s390x/Makefile.objs            |  3 +-
hw/s390x/s390-pci-bus.c           |  4 +--
hw/s390x/s390-pci-bus.h           |  4 +--
hw/s390x/s390-pci-stub.c          | 74 +++++++++++++++++++++++++++++++++++++++
hw/s390x/s390-virtio-ccw.c        | 12 ++++---
hw/s390x/sclp.c                   | 19 +++++++---
include/hw/pci/pci.h              |  2 ++
target/s390x/ioinst.c             | 16 +++++++++
target/s390x/kvm.c                | 64 +++++++++++++++++++++++++--------
13 files changed, 189 insertions(+), 32 deletions(-)
create mode 100644 hw/s390x/s390-pci-stub.c
[Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Cornelia Huck 6 years, 8 months ago
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

Cornelia Huck (9):
  kvm: remove hard dependency on pci
  s390x/pci: add stubs
  s390x: chsc nt2 events are pci-only
  s390x/pci: do not advertise pci on non-pci builds
  s390x/ccw: create s390 phb conditionally
  s390x/sclp: properly guard pci-specific functions
  s390x/pci: fence off instructions for non-pci
  s390x/kvm: msi route fixup for non-pci
  s390x: refine pci dependencies

 accel/kvm/kvm-all.c               |  6 ++--
 default-configs/s390x-softmmu.mak |  2 +-
 hw/pci/pci-stub.c                 | 13 +++++++
 hw/pci/pci.c                      |  2 ++
 hw/s390x/Makefile.objs            |  3 +-
 hw/s390x/s390-pci-bus.c           |  4 +--
 hw/s390x/s390-pci-bus.h           |  4 +--
 hw/s390x/s390-pci-stub.c          | 74 +++++++++++++++++++++++++++++++++++++++
 hw/s390x/s390-virtio-ccw.c        | 12 ++++---
 hw/s390x/sclp.c                   | 19 +++++++---
 include/hw/pci/pci.h              |  2 ++
 target/s390x/ioinst.c             | 16 +++++++++
 target/s390x/kvm.c                | 64 +++++++++++++++++++++++++--------
 13 files changed, 189 insertions(+), 32 deletions(-)
 create mode 100644 hw/s390x/s390-pci-stub.c

-- 
2.13.3


Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Cornelia Huck 6 years, 8 months ago
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?

Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Cornelia Huck 6 years, 8 months ago
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 :)

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/
-- 
2.13.4


Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Thomas Huth 6 years, 8 months ago
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


> 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/
> 


Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Cornelia Huck 6 years, 8 months ago
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/
> >   
> 


Re: [Qemu-devel] [PATCH v4 0/9] s390x: zPCI detangling
Posted by Thomas Huth 6 years, 8 months ago
On 08.08.2017 11:46, Cornelia Huck wrote:
> 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?

I don't think that this would work: configure is run once for all
targets, but the CONFIG_PCI and CONFIG_CCW settings are only valid for
individual targets, so you can not use the value of these config
variables during "configure" yet.

 Thomas