[PATCH 00/14] paravirt: cleanup and reorg

Juergen Gross
2025-09-11T06:34:47Z

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 6-12 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 13+14 are more like RFC material: patch 13 is doing some
preparation work to enable patch 14 to move all spinlock related
paravirt functions into qspinlock.h. If this approach is accepted,
I'd like to continue with this work by moving most (or all?)
paravirt functions from paravirt.h into the headers where their
native counterparts are defined. This is meant to keep the native
and paravirt function definitions together in one place and
hopefully to be able to reduce the include hell with paravirt.

Juergen Gross (14):
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: allow pv-calls outside paravirt.h
x86/pvlocks: move paravirt spinlock functions into qspinlock.h

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 | 1 -
arch/x86/include/asm/apic.h | 4 -
arch/x86/include/asm/highmem.h | 1 -
arch/x86/include/asm/mmu_context.h | 1 -
arch/x86/include/asm/mshyperv.h | 1 -
arch/x86/include/asm/paravirt.h | 166 ------------------
arch/x86/include/asm/paravirt_api_clock.h | 1 -
arch/x86/include/asm/paravirt_types.h | 82 +++++++--
arch/x86/include/asm/pgtable_32.h | 1 -
arch/x86/include/asm/qspinlock.h | 49 +++++-
arch/x86/include/asm/spinlock.h | 1 -
arch/x86/include/asm/timer.h | 1 +
arch/x86/include/asm/tlbflush.h | 4 -
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 | 1 +
arch/x86/kernel/kvmclock.c | 1 +
arch/x86/kernel/paravirt.c | 16 --
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/spinlock.c | 1 -
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 +-
57 files changed, 182 insertions(+), 362 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
delete mode 100644 arch/x86/include/asm/paravirt_api_clock.h

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2.51.0