Re: [PATCH v3 00/21] x86/xen: untangle PV and PVHVM guest support code

From: Juergen Gross
Date: Wed Mar 15 2017 - 05:42:57 EST


On 14/03/17 18:35, Vitaly Kuznetsov wrote:
> Changes since v2:
> - Rebase to 4.11.0-rc1+
> - XEN_HAVE_PVMMU moved to config XEN_PV [Juergen Gross]
> - .pin_vcpu kept for x86_hyper_xen_hvm to support PVH Dom0 in future
> [Juergen Gross]
> - 'extern' qualifiers dropped from newly introduced function prototypes
> in headers [Juergen Gross]
> - A couple of #includes added to address build issues with different
> configs [kbuild test robot].
> - Juergen reviewed-bys added (hope they stand with the above mentioned
> changes).

They do.

In case nobody objects I'll take this series for 4.12.


Juergen

>
> The series can also be pulled from https://github.com/vittyvk/linux.git
> (xen_pv_hvm_split_v3 branch).
>
> Some patches are known to produce checkpatch.pl WARNINGS and a couple of
> ERRORs, I fixed a few (mostly in _hvm* code I split) and I refrained from
> fixing the rest to make it easier to review. I think that we may leave PV
> code as it is as sooner or later it will go away.
>
> Original description:
>
> I have a long-standing idea to separate PV and PVHVM code in kernel and
> introduce Kconfig options to make it possible to enable the required
> parts only breaking the current 'all or nothing' approach.
>
> Motivation:
> - Xen related x86 code in kernel is rather big and it is unclear which
> parts of it are required for PV, for HVM or for both. With PVH coming
> into picture is becomes even more tangled. It makes it hard to
> understand/audit the code.
>
> - In some case we may want to avoid bloating kernel by supporting Xen
> guests we don't need. In particular, 90% of the code in arch/x86/xen/ is
> required to support PV guests and one may require PVHVM support only.
>
> - PV guests are supposed to go away one day and such code separation would
> help us to get ready.
>
> This series adds XEN_PV Kconfig option and makes it possible to build PV-only
> and PVHVM-only kernels. It also makes it possible to disable Dom0 support.
>
> Some patches are rather big but this is mostly just moving code around, no
> functional changes intended. I smoke tested it with PV-only and PVHVM-only
> builds, booted and did save/restore test. I also tried the newly introduced
> PVHv2 guest, it even worked!
>
> Vitaly Kuznetsov (21):
> x86/xen: separate PV and HVM hypervisors
> x86/xen: globalize have_vcpu_info_placement
> x86/xen: add CONFIG_XEN_PV to Kconfig
> x86/xen: split off enlighten_pvh.c
> x86/xen: split off enlighten_hvm.c
> x86/xen: split off enlighten_pv.c
> x86/xen: split xen_smp_intr_init()/xen_smp_intr_free()
> x86/xen: split xen_smp_prepare_boot_cpu()
> x86/xen: split xen_cpu_die()
> x86/xen: split off smp_hvm.c
> x86/xen: split off smp_pv.c
> x86/xen: split off mmu_hvm.c
> x86/xen: split off mmu_pv.c
> x86/xen: split suspend.c for PV and PVHVM guests
> x86/xen: put setup.c, pmu.c and apic.c under CONFIG_XEN_PV
> x86/xen: define startup_xen for XEN PV only
> x86/xen: create stubs for HVM-only builds in page.h
> xen/balloon: decorate PV-only parts with #ifdef CONFIG_XEN_PV
> xen: create xen_create/destroy_contiguous_region() stubs for PVHVM
> only builds
> x86/xen: enable PVHVM-only builds
> x86/xen: rename some PV-only functions in smp_pv.c
>
> arch/x86/include/asm/hypervisor.h | 3 +-
> arch/x86/include/asm/xen/page.h | 25 +
> arch/x86/kernel/cpu/hypervisor.c | 7 +-
> arch/x86/kernel/process_64.c | 2 +-
> arch/x86/xen/Kconfig | 33 +-
> arch/x86/xen/Makefile | 16 +-
> arch/x86/xen/enlighten.c | 1925 +------------------------
> arch/x86/xen/enlighten_hvm.c | 213 +++
> arch/x86/xen/enlighten_pv.c | 1522 ++++++++++++++++++++
> arch/x86/xen/enlighten_pvh.c | 115 ++
> arch/x86/xen/mmu.c | 2776 +------------------------------------
> arch/x86/xen/mmu_hvm.c | 79 ++
> arch/x86/xen/mmu_pv.c | 2635 +++++++++++++++++++++++++++++++++++
> arch/x86/xen/pmu.h | 5 +
> arch/x86/xen/smp.c | 517 +------
> arch/x86/xen/smp.h | 16 +
> arch/x86/xen/smp_hvm.c | 58 +
> arch/x86/xen/smp_pv.c | 500 +++++++
> arch/x86/xen/suspend.c | 54 -
> arch/x86/xen/suspend_hvm.c | 22 +
> arch/x86/xen/suspend_pv.c | 46 +
> arch/x86/xen/xen-head.S | 4 +
> arch/x86/xen/xen-ops.h | 23 +
> drivers/xen/balloon.c | 30 +-
> include/xen/xen-ops.h | 14 +
> 25 files changed, 5461 insertions(+), 5179 deletions(-)
> create mode 100644 arch/x86/xen/enlighten_hvm.c
> create mode 100644 arch/x86/xen/enlighten_pv.c
> create mode 100644 arch/x86/xen/enlighten_pvh.c
> create mode 100644 arch/x86/xen/mmu_hvm.c
> create mode 100644 arch/x86/xen/mmu_pv.c
> create mode 100644 arch/x86/xen/smp_hvm.c
> create mode 100644 arch/x86/xen/smp_pv.c
> create mode 100644 arch/x86/xen/suspend_hvm.c
> create mode 100644 arch/x86/xen/suspend_pv.c
>