Re: [Xen-devel] [PATCH 8/8] raisin: RFC Add blktap2 as an external tree

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Mon, 20 Apr 2015, George Dunlap wrote:
> On 04/17/2015 11:50 AM, Stefano Stabellini wrote:
> > On Thu, 16 Apr 2015, George Dunlap wrote:
> >> Until we start hosting the blktap repo on xenbits, use the one from github.
> >>
> >> Also, we need to pass in the directories where to find the
> >> libblktapctl headers in the Xen build.
> >>
> >> Signed-off-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> >> ---
> >> Note: For now use the "upstream" XenServer repo.
> >>
> >> Also, to build with this you need the patches to allow Xen to use an 
> >> out-of-tree blktap,
> >> which can be found here:
> >>
> >> git://xenbits.xen.org/people/gdunlap/xen.git  out/blktap25/rfc-v2
> >>
> >> CC: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> >> ---
> >>  components/blktap | 47 +++++++++++++++++++++++++++++++++++++++++++++++
> >>  components/series |  1 +
> >>  components/xen    |  5 +++++
> >>  defconfig         |  9 ++++++---
> >>  4 files changed, 59 insertions(+), 3 deletions(-)
> >>  create mode 100644 components/blktap
> >>
> >> diff --git a/components/blktap b/components/blktap
> >> new file mode 100644
> >> index 0000000..3062b2a
> >> --- /dev/null
> >> +++ b/components/blktap
> >> @@ -0,0 +1,47 @@
> >> +#!/usr/bin/env bash
> >> +
> >> +function blktap_check_package() {
> >> +    local DEP_Debian_common="build-essential autoconf libtool tar 
> >> libaio-dev uuid-dev openssl-dev"
> >> +    local DEP_Debian_x86_32="$DEP_Debian_common"
> >> +    local DEP_Debian_x86_64="$DEP_Debian_x86_32"
> >> +    local DEP_Debian_arm32="$DEP_Debian_common"
> >> +    local DEP_Debian_arm64="$DEP_Debian_arm32"
> >> +
> >> +    local DEP_Fedora_common="make gcc python-devel autoconf libtool tar 
> >> file libaio-devel libuuid-devel openssl-devel"
> >> +    local DEP_Fedora_x86_32="$DEP_Fedora_common"
> >> +    local DEP_Fedora_x86_64="$DEP_Fedora_x86_32"
> >> +
> >> +    local DEP_CentOS_common="make gcc python-devel autoconf libtool tar 
> >> file libaio-devel libuuid-devel openssl-devel"
> > 
> > DEP_CentOS_common="$DEP_Fedora_common"
> > 
> > 
> >> +    local DEP_CentOS_x86_32="$DEP_Redhat_common"
> >> +    local DEP_CentOS_x86_64="$DEP_Redhat_x86_32"
> > 
> > Redhat? I don't know no Redhat.
> 
> Sorry, artifacts from a previous version of the patch...
> >> +    fi
> >> +}
> >> +
> >> +function blktap_configure() {
> >> +    :
> >> +}
> >> +
> >> +function blktap_unconfigure() {
> >> +    :
> >> +}
> > 
> > Much better than my echo. Maybe submit a patch to replace useless echo
> > in configure and unconfigure functions with :
> 
> I can put it on my to-do list, but it may be a while before it reaches
> the top. :-)
> 
> >> diff --git a/components/series b/components/series
> >> index 8f614f0..953800a 100644
> >> --- a/components/series
> >> +++ b/components/series
> >> @@ -1,3 +1,4 @@
> >> +blktap
> >>  xen
> > 
> > I take this is on purpose so that blktap is built before xen
> 
> Yes, as Xen has to link against the libraries.
> 
> >>  qemu
> >>  grub
> >> diff --git a/components/xen b/components/xen
> >> index f2e1254..03a1970 100644
> >> --- a/components/xen
> >> +++ b/components/xen
> >> @@ -29,7 +29,12 @@ function xen_build() {
> >>      cd "$BASEDIR"
> >>      git-checkout $XEN_URL $XEN_REVISION xen-dir
> >>      cd xen-dir
> >> +    CFLAGS="-I$INST_DIR/$PREFIX/include/blktap 
> >> -I$INST_DIR/$PREFIX/include/vhd" \
> >> +    LDFLAGS="-L$INST_DIR/$PREFIX/lib 
> >> -Wl,-rpath-link=$INST_DIR/$PREFIX/lib" \
> >>      ./configure --prefix=$PREFIX 
> >> --with-system-qemu=/usr/bin/qemu-system-i386
> >> +    CFLAGS_libblktapctl="-I$INST_DIR/$PREFIX/include/blktap 
> >> -I$INST_DIR/$PREFIX/include/vhd" \
> >> +    LDLIBS_libblktapctl="-L$INST_DIR/$PREFIX/lib -lblktapctl" \
> >> +    SHLIB_libblktapctl="-Wl,-rpath-link=$INST_DIR/$PREFIX/lib" \
> > 
> > Does this work even if blktap is actually disabled in the raisin build?
> > If so, then fine.
> 
> I don't think I've tested it, but in theory yes it should work.  If
> blktap support isn't specified, the patch series I submitted to
> xen-unstable will automatically enable blktap if found and disable it if
> not found.  So if you have a clean raisin repo and just build the xen
> component, it should build it without blktap.
> 
> (With my patches,  if you specify --enable-blktap and it can't find it,
> config will throw an error.  But we're not enabling it.)

If you test it and it works both with and without blktap, then I am OK
with it as is.


> > Actually I think that the xen configure script should be able to figure
> > out whether it can pick up blktap from an external location
> > automatically with the CFLAGS and LDFLAGS you set.
> 
> Actually, what would be better is if you could just set
> "-I$INST_DIR/$PREFIX/include" and "-L$INST_DIR/$PREFIX/lib" and be done
> with it.  But the blktap2 headers are broken at the moment: they're
> placed in subdirectories on install time that don't reflect the
> directory structure used when building, so if you don't specify both
> subdirectories explicitly, it won't compile.
> 
> That's something I plan to fix, but it may take a bit to get back to it.
> 
>  -George
> 

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