Re: [Xen-devel] [PATCH QEMU-XEN v4 9/9] xen: make it possible to build without the Xen PV domain builder

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Wed, 21 Oct 2015, Ian Campbell wrote:
> Until the previous patch this relied on xc_fd(), which was only
> implemented for Xen 4.0 and earlier.
> 
> Given this wasn't working since Xen 4.0 I have marked this as disabled
> by default.
> 
> Removing this support drops the use of a bunch of symbols from
> libxenctrl, specifically:
> 
>   - xc_domain_create
>   - xc_domain_destroy
>   - xc_domain_getinfo
>   - xc_domain_max_vcpus
>   - xc_domain_setmaxmem
>   - xc_domain_unpause
>   - xc_evtchn_alloc_unbound
>   - xc_linux_build
> 
> This is another step towards only using Xen libraries which provide a
> stable inteface.
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
> v4: Fixed all checkpatch errors.
>     Disabled by default.
> ---
>  configure                 | 17 +++++++++++++++++
>  hw/xenpv/Makefile.objs    |  4 +++-
>  hw/xenpv/xen_machine_pv.c | 14 ++++++++++----
>  3 files changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/configure b/configure
> index fe0a39d..9eab587 100755
> --- a/configure
> +++ b/configure
> @@ -910,6 +910,10 @@ for opt do
>    ;;
>    --enable-xen-pci-passthrough) xen_pci_passthrough="yes"
>    ;;
> +  --disable-xen-pv-domain-build) xen_pv_domain_build="no"
> +  ;;
> +  --enable-xen-pv-domain-build) xen_pv_domain_build="yes"
> +  ;;
>    --disable-brlapi) brlapi="no"
>    ;;
>    --enable-brlapi) brlapi="yes"
> @@ -2113,6 +2117,15 @@ if test "$xen_pci_passthrough" != "no"; then
>    fi
>  fi
>  
> +if test "$xen_pv_domain_build" != "no"; then
> +  if test "$xen_pv_domain_build" = "yes" &&
> +     test "$xen" != "yes"; then
> +      error_exit "User requested Xen PV domain builder support" \
> +              "which requires Xen support."
> +  fi
> +  xen_pv_domain_build=no
> +fi

Can we simplify this to:

  if test "$xen_pv_domain_build" = "yes" &&
       test "$xen" != "yes"; then
        error_exit "User requested Xen PV domain builder support" \
                 "which requires Xen support."
    fi
  fi

and move xen_pv_domain_build=no at the beginning of the file?


>  ##########################################
>  # libtool probe
>  
> @@ -4393,6 +4406,7 @@ fi
>  echo "xen support       $xen"
>  if test "$xen" = "yes" ; then
>    echo "xen ctrl version  $xen_ctrl_version"
> +  echo "pv dom build     $xen_pv_domain_build"
>  fi
>  echo "brlapi support    $brlapi"
>  echo "bluez  support    $bluez"
> @@ -4725,6 +4739,9 @@ fi
>  if test "$xen" = "yes" ; then
>    echo "CONFIG_XEN_BACKEND=y" >> $config_host_mak
>    echo "CONFIG_XEN_CTRL_INTERFACE_VERSION=$xen_ctrl_version" >> 
> $config_host_mak
> +  if test "$xen_pv_domain_build" = "yes" ; then
> +    echo "CONFIG_XEN_PV_DOMAIN_BUILD=y" >> $config_host_mak
> +  fi
>  fi
>  if test "$linux_aio" = "yes" ; then
>    echo "CONFIG_LINUX_AIO=y" >> $config_host_mak
> diff --git a/hw/xenpv/Makefile.objs b/hw/xenpv/Makefile.objs
> index 49f6e9e..bbf5873 100644
> --- a/hw/xenpv/Makefile.objs
> +++ b/hw/xenpv/Makefile.objs
> @@ -1,2 +1,4 @@
>  # Xen PV machine support
> -obj-$(CONFIG_XEN) += xen_domainbuild.o xen_machine_pv.o
> +obj-$(CONFIG_XEN) += xen_machine_pv.o
> +# Xen PV machine builder support
> +obj-$(CONFIG_XEN_PV_DOMAIN_BUILD) += xen_domainbuild.o
> diff --git a/hw/xenpv/xen_machine_pv.c b/hw/xenpv/xen_machine_pv.c
> index 2e545d2..e5b3698 100644
> --- a/hw/xenpv/xen_machine_pv.c
> +++ b/hw/xenpv/xen_machine_pv.c
> @@ -30,9 +30,6 @@
>  
>  static void xen_init_pv(MachineState *machine)
>  {
> -    const char *kernel_filename = machine->kernel_filename;
> -    const char *kernel_cmdline = machine->kernel_cmdline;
> -    const char *initrd_filename = machine->initrd_filename;
>      DriveInfo *dinfo;
>      int i;
>  
> @@ -46,13 +43,22 @@ static void xen_init_pv(MachineState *machine)
>      case XEN_ATTACH:
>          /* nothing to do, xend handles everything */
>          break;
> -    case XEN_CREATE:
> +    case XEN_CREATE: {
> +#ifdef CONFIG_XEN_PV_DOMAIN_BUILD
> +        const char *kernel_filename = machine->kernel_filename;
> +        const char *kernel_cmdline = machine->kernel_cmdline;
> +        const char *initrd_filename = machine->initrd_filename;
>          if (xen_domain_build_pv(kernel_filename, initrd_filename,
>                                  kernel_cmdline) < 0) {
>              fprintf(stderr, "xen pv domain creation failed\n");
>              exit(1);
>          }
> +#else
> +        fprintf(stderr, "xen pv domain creation not supported\n");
> +        exit(1);
> +#endif
>          break;
> +    }
>      case XEN_EMULATE:
>          fprintf(stderr, "xen emulation not implemented (yet)\n");
>          exit(1);

Please add a default case with an error and place the XEN_CREATE
entirely within the ifdef CONFIG_XEN_PV_DOMAIN_BUILD.

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