[PATCH v3 00/21] paravirt: cleanup and reorg

Juergen Gross jgross at suse.com
Mon Nov 24 20:42:54 AEDT 2025


Ping?

I think at least the first 12 patches can just go in.

The others still lack review.


Juergen

On 06.10.25 09:45, Juergen Gross wrote:
> Some cleanups and reorg of paravirt code and headers:
> 
> - The first 2 patches should be not controversial at all, as they
>    remove just some no longer needed #include and struct forward
>    declarations.
> 
> - The 3rd patch is removing CONFIG_PARAVIRT_DEBUG, which IMO has
>    no real value, as it just changes a crash to a BUG() (the stack
>    trace will basically be the same). As the maintainer of the main
>    paravirt user (Xen) I have never seen this crash/BUG() to happen.
> 
> - The 4th patch is just a movement of code.
> 
> - I don't know for what reason asm/paravirt_api_clock.h was added,
>    as all archs supporting it do it exactly in the same way. Patch
>    5 is removing it.
> 
> - Patches 6-14 are streamlining the paravirt clock interfaces by
>    using a common implementation across architectures where possible
>    and by moving the related code into common sched code, as this is
>    where it should live.
> 
> - Patches 15-20 are more like RFC material preparing the paravirt
>    infrastructure to support multiple pv_ops function arrays.
>    As a prerequisite for that it makes life in objtool much easier
>    with dropping the Xen static initializers of the pv_ops sub-
>    structures, which is done in patches 15-17.
>    Patches 18-20 are doing the real preparations for multiple pv_ops
>    arrays and using those arrays in multiple headers.
> 
> - Patch 21 is an example how the new scheme can look like using the
>    PV-spinlocks.
> 
> Changes in V2:
> - new patches 13-18 and 20
> - complete rework of patch 21
> 
> Changes in V3:
> - fixed 2 issues detected by kernel test robot
> 
> Juergen Gross (21):
>    x86/paravirt: Remove not needed includes of paravirt.h
>    x86/paravirt: Remove some unneeded struct declarations
>    x86/paravirt: Remove PARAVIRT_DEBUG config option
>    x86/paravirt: Move thunk macros to paravirt_types.h
>    paravirt: Remove asm/paravirt_api_clock.h
>    sched: Move clock related paravirt code to kernel/sched
>    arm/paravirt: Use common code for paravirt_steal_clock()
>    arm64/paravirt: Use common code for paravirt_steal_clock()
>    loongarch/paravirt: Use common code for paravirt_steal_clock()
>    riscv/paravirt: Use common code for paravirt_steal_clock()
>    x86/paravirt: Use common code for paravirt_steal_clock()
>    x86/paravirt: Move paravirt_sched_clock() related code into tsc.c
>    x86/paravirt: Introduce new paravirt-base.h header
>    x86/paravirt: Move pv_native_*() prototypes to paravirt.c
>    x86/xen: Drop xen_irq_ops
>    x86/xen: Drop xen_cpu_ops
>    x86/xen: Drop xen_mmu_ops
>    objtool: Allow multiple pv_ops arrays
>    x86/paravirt: Allow pv-calls outside paravirt.h
>    x86/paravirt: Specify pv_ops array in paravirt macros
>    x86/pvlocks: Move paravirt spinlock functions into own header
> 
>   arch/Kconfig                                  |   3 +
>   arch/arm/Kconfig                              |   1 +
>   arch/arm/include/asm/paravirt.h               |  22 --
>   arch/arm/include/asm/paravirt_api_clock.h     |   1 -
>   arch/arm/kernel/Makefile                      |   1 -
>   arch/arm/kernel/paravirt.c                    |  23 --
>   arch/arm64/Kconfig                            |   1 +
>   arch/arm64/include/asm/paravirt.h             |  14 -
>   arch/arm64/include/asm/paravirt_api_clock.h   |   1 -
>   arch/arm64/kernel/paravirt.c                  |  11 +-
>   arch/loongarch/Kconfig                        |   1 +
>   arch/loongarch/include/asm/paravirt.h         |  13 -
>   .../include/asm/paravirt_api_clock.h          |   1 -
>   arch/loongarch/kernel/paravirt.c              |  10 +-
>   arch/powerpc/include/asm/paravirt.h           |   3 -
>   arch/powerpc/include/asm/paravirt_api_clock.h |   2 -
>   arch/powerpc/platforms/pseries/setup.c        |   4 +-
>   arch/riscv/Kconfig                            |   1 +
>   arch/riscv/include/asm/paravirt.h             |  14 -
>   arch/riscv/include/asm/paravirt_api_clock.h   |   1 -
>   arch/riscv/kernel/paravirt.c                  |  11 +-
>   arch/x86/Kconfig                              |   8 +-
>   arch/x86/entry/entry_64.S                     |   1 -
>   arch/x86/entry/vsyscall/vsyscall_64.c         |   1 -
>   arch/x86/hyperv/hv_spinlock.c                 |  11 +-
>   arch/x86/include/asm/apic.h                   |   4 -
>   arch/x86/include/asm/highmem.h                |   1 -
>   arch/x86/include/asm/mshyperv.h               |   1 -
>   arch/x86/include/asm/paravirt-base.h          |  29 ++
>   arch/x86/include/asm/paravirt-spinlock.h      | 146 ++++++++
>   arch/x86/include/asm/paravirt.h               | 331 +++++-------------
>   arch/x86/include/asm/paravirt_api_clock.h     |   1 -
>   arch/x86/include/asm/paravirt_types.h         | 269 +++++++-------
>   arch/x86/include/asm/pgtable_32.h             |   1 -
>   arch/x86/include/asm/ptrace.h                 |   2 +-
>   arch/x86/include/asm/qspinlock.h              |  89 +----
>   arch/x86/include/asm/spinlock.h               |   1 -
>   arch/x86/include/asm/timer.h                  |   1 +
>   arch/x86/include/asm/tlbflush.h               |   4 -
>   arch/x86/kernel/Makefile                      |   2 +-
>   arch/x86/kernel/apm_32.c                      |   1 -
>   arch/x86/kernel/callthunks.c                  |   1 -
>   arch/x86/kernel/cpu/bugs.c                    |   1 -
>   arch/x86/kernel/cpu/vmware.c                  |   1 +
>   arch/x86/kernel/kvm.c                         |  11 +-
>   arch/x86/kernel/kvmclock.c                    |   1 +
>   arch/x86/kernel/paravirt-spinlocks.c          |  26 +-
>   arch/x86/kernel/paravirt.c                    |  42 +--
>   arch/x86/kernel/tsc.c                         |  10 +-
>   arch/x86/kernel/vsmp_64.c                     |   1 -
>   arch/x86/kernel/x86_init.c                    |   1 -
>   arch/x86/lib/cache-smp.c                      |   1 -
>   arch/x86/mm/init.c                            |   1 -
>   arch/x86/xen/enlighten_pv.c                   |  82 ++---
>   arch/x86/xen/irq.c                            |  20 +-
>   arch/x86/xen/mmu_pv.c                         | 100 ++----
>   arch/x86/xen/spinlock.c                       |  11 +-
>   arch/x86/xen/time.c                           |   2 +
>   drivers/clocksource/hyperv_timer.c            |   2 +
>   drivers/xen/time.c                            |   2 +-
>   include/linux/sched/cputime.h                 |  18 +
>   kernel/sched/core.c                           |   5 +
>   kernel/sched/cputime.c                        |  13 +
>   kernel/sched/sched.h                          |   3 +-
>   tools/objtool/arch/x86/decode.c               |   8 +-
>   tools/objtool/check.c                         |  78 ++++-
>   tools/objtool/include/objtool/check.h         |   2 +
>   67 files changed, 659 insertions(+), 827 deletions(-)
>   delete mode 100644 arch/arm/include/asm/paravirt.h
>   delete mode 100644 arch/arm/include/asm/paravirt_api_clock.h
>   delete mode 100644 arch/arm/kernel/paravirt.c
>   delete mode 100644 arch/arm64/include/asm/paravirt_api_clock.h
>   delete mode 100644 arch/loongarch/include/asm/paravirt_api_clock.h
>   delete mode 100644 arch/powerpc/include/asm/paravirt_api_clock.h
>   delete mode 100644 arch/riscv/include/asm/paravirt_api_clock.h
>   create mode 100644 arch/x86/include/asm/paravirt-base.h
>   create mode 100644 arch/x86/include/asm/paravirt-spinlock.h
>   delete mode 100644 arch/x86/include/asm/paravirt_api_clock.h
> 

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