Re: Xen's Linux kernel config options V2

["Luis R. Rodriguez" <mcgrof@do-not-panic.com>]

On Wed, Feb 4, 2015 at 6:57 AM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Wed, 4 Feb 2015, David Vrabel wrote:
>> On 16/12/14 16:21, Juergen Gross wrote:
>> > Hi,
>> >
>> > This is a design proposal for a rework of the config options on the
>> > Linux kernel which are related to Xen.
>> >
>> > The need to do so arose from the fact that it is currently not
>> > possible to build the Xen frontend drivers for a non-pvops kernel,
>> > e.g. to run them in a HVM-domain. There are more drawbacks in the
>> > current config options to which I'll come later.
>> >
>> > Option                          Selects                 Depends
>> > ----------------------------------------------------------------------
>> > XEN
>> >   XEN_PV(x86)                   XEN_HAVE_PVMMU
>> >                                 PARAVIRT
>> >                                 PARAVIRT_CLOCK
>> >   XEN_PVH(x86)                  XEN_PVHVM
>> >                                 PARAVIRT
>> >                                 PARAVIRT_CLOCK
>> >   XEN_PVHVM                     PARAVIRT
>> >                                 PARAVIRT_CLOCK
>
> PARAVIRT_CLOCK and PARAVIRT are x86 specific.
> Given that there is no CONFIG_PV or CONFIG_PVH or even CONFIG_PVHVM on
> arm and arm64 as there is just one type of guest, I would rather just
> have CONFIG_XEN there.

Interesting, right now we have as part of the recommended change for
XEN_BACKEND:

Option                          Selects                 Depends
----------------------------------------------------------------------
XEN
  XEN_BACKEND                   SWIOTLB_XEN(arm,arm64)  XEN_PV(x86) ||
                                                        XEN_PVH(x86) ||
                                                        XEN_PVHVM

How would we ensure to enable XEN_BACKEND for arm then?

>> >   XEN_BACKEND                   SWIOTLB_XEN(arm,arm64)  XEN_PV(x86) ||
>> >                                                         XEN_PVH(x86) ||
>> >                                                         XEN_PVHVM
>> >     XEN_BLKDEV_BACKEND
>> >     XEN_PCIDEV_BACKEND(x86)
>> >     XEN_SCSI_BACKEND
>> >     XEN_NETDEV_BACKEND
>> >   PCI_XEN(x86)                  SWIOTLB_XEN
>> >   XEN_DOM0                      XEN_BACKEND             XEN_PV(x86) ||
>> >                                 PCI_XEN(x86)            XEN_PVH(x86)
>> >     XEN_ACPI_HOTPLUG_MEMORY                             XEN_STUB
>> >     XEN_ACPI_HOTPLUG_CPU                                XEN_STUB
>> >     XEN_MCE_LOG(x86)
>> >   XEN_MAX_DOMAIN_MEMORY(x86)
>> >   XEN_SAVE_RESTORE(x86)
>> >   XEN_DEBUG_FS
>> >   XEN_WDT
>> >   XEN_BALLOON
>> >     XEN_SELFBALLOONING                                  XEN_TMEM
>> >     XEN_BALLOON_MEMORY_HOTPLUG
>> >     XEN_SCRUB_PAGES
>> >   XENFS                         XEN_PRIVCMD
>> >     XEN_COMPAT_XENFS
>> >   XEN_SYS_HYPERVISOR
>> >   XEN_DEV_EVTCHN
>> >   XEN_GNTDEV
>> >   XEN_GRANT_DEV_ALLOC
>> >   SWIOTLB_XEN
>> >   XEN_TMEM
>
> not available on arm and arm64

Can you clarify if you meant only XEN_TMEM or all the above here?

>> >   XEN_PRIVCMD
>> >   XEN_STUB(x86_64)                                      BROKEN
>> >   XEN_ACPI_PROCESSOR(x86)
>> >   XEN_HAVE_PVMMU
>
> x86 specific

Likewise, all of the above quoted options ?

>> >   XEN_EFI(x64)
>
> FYI soon to be available on arm

OK thanks.

>> >   XEN_XENBUS_FRONTEND
>> > XEN_FRONTEND                    XEN
>> >                                 XEN_XENBUS_FRONTEND
>> >   XEN_FBDEV_FRONTEND            INPUT_XEN_KBDDEV_FRONTEND
>> >   XEN_BLKDEV_FRONTEND
>> >   HVC_XEN_FRONTEND              HVC_XEN
>> >   TCG_XEN
>> >   XEN_PCIDEV_FRONTEND           PCI_XEN
>
> x86 specific for the moment

All?

>> >   XEN_SCSI_FRONTEND
>> >   INPUT_XEN_KBDDEV_FRONTEND
>> >   XEN_NETDEV_FRONTEND
>> >   XEN_PLATFORM_PCI
>
> definitely x86 only

All?

  Luis