Re: [Xen-devel] [PATCH raisin 4/4] Update to 4.7, update qemu and qemu_traditional recipes

[George Dunlap <george.dunlap@xxxxxxxxxx>]

On 14/06/16 11:08, Stefano Stabellini wrote:
> On Tue, 14 Jun 2016, George Dunlap wrote:
>> On 14/06/16 10:46, Stefano Stabellini wrote:
>>> On Mon, 13 Jun 2016, George Dunlap wrote:
>>>> Add a 4.7 config file, make it the default.
>>>>
>>>> Also update the qemu and qemu_traditional recipies after Ian Cambell's
>>>> work to split off separate libraries.
>>>>
>>>> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxx>
>>>> ---
>>>> CC: Stefano Stabellini <sstabellini@xxxxxxxxxx>
>>>> ---
>>>>  components/qemu             | 21 +++++++++++++--------
>>>>  components/qemu_traditional |  2 +-
>>>>  configs/config-4.7          |  8 ++++++++
>>>>  defconfig                   |  2 +-
>>>>  4 files changed, 23 insertions(+), 10 deletions(-)
>>>>
>>>> diff --git a/components/qemu b/components/qemu
>>>> index e0d92a5..8624b50 100644
>>>> --- a/components/qemu
>>>> +++ b/components/qemu
>>>> @@ -23,15 +23,20 @@ function qemu_build() {
>>>>      cd "$BASEDIR"
>>>>      git-checkout $QEMU_URL $QEMU_REVISION qemu-dir
>>>>      cd qemu-dir
>>>> -    ./configure --enable-xen --target-list=i386-softmmu --prefix=$PREFIX \
>>>> -        --extra-cflags="-I$INST_DIR/$PREFIX/include" \
>>>> -        --extra-ldflags="-L$INST_DIR/$PREFIX/lib 
>>>> -Wl,-rpath-link=$INST_DIR/$PREFIX/lib \
>>>> +
>>>> +    ./configure --enable-xen --target-list=i386-softmmu \
>>>> +          --prefix=$PREFIX \
>>>> +          --extra-cflags="-DXC_WANT_COMPAT_EVTCHN_API=1 \
>>>> +          -DXC_WANT_COMPAT_GNTTAB_API=1 \
>>>> +          -DXC_WANT_COMPAT_MAP_FOREIGN_API=1 \
>>>> +                -I$INST_DIR/$PREFIX/include" \
>>>> +          --extra-ldflags="-L$INST_DIR/$PREFIX/lib 
>>>> -Wl,-rpath-link=$INST_DIR/$PREFIX/lib \
>>>>                           -L$INST_DIR/$PREFIX/lib64 
>>>> -Wl,-rpath-link=$INST_DIR/$PREFIX/lib64" \
>>>> -        --disable-kvm \
>>>> -        --disable-docs \
>>>> -        --bindir=$PREFIX/lib/xen/bin \
>>>> -        --datadir=$PREFIX/share/qemu-xen \
>>>> -        --disable-guest-agent
>>>> +          --bindir=$PREFIX/lib/xen/bin \
>>>> +          --datadir=$PREFIX/share/qemu-xen \
>>>> +          --disable-kvm \
>>>> +          --disable-docs \
>>>> +          --disable-guest-agent
>>>
>>> This is adding XC_WANT_COMPAT_EVTCHN_API=1, etc, unconditionally. If we
>>> make this change, will raisin still be able to buil an older qemu
>>> against an older xen?
>>
>> I've tested this with XEN_RELEASE set to 4.5 and 4.6, and it builds just
>> fine.  The #define is just ignored, since neither Xen nor qemu in the
>> 4.5 and 4.6 branches know anything about it.
>>
>> If part of our goal is to be a repository of the canonical way to build
>> things, though, perhaps it would be better to have the extra flags be
>> conditional on the value of XEN_RELEASE.
> 
> If we are sure that it's ignored than it might be benign. Maybe we
> should just add an in-code comment to explain why we added it though.

Well really, I think that the detection should be put into the qemu
configure scripts -- i.e., it should detect that there's the new API and
add the appropriate #defines itself.  But that's the sort of change I
don't think there will be a lot of enthusiasm for. :-)

I'll add a comment.

 -George



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