* [PATCH 00/14] paravirt: cleanup and reorg
@ 2025-09-11 6:34 Juergen Gross
2025-09-11 6:34 ` [PATCH 05/14] paravirt: remove asm/paravirt_api_clock.h Juergen Gross
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Juergen Gross @ 2025-09-11 6:34 UTC (permalink / raw)
To: linux-kernel, x86, linux-hyperv, virtualization, loongarch,
linuxppc-dev, linux-riscv, kvm
Cc: Juergen Gross, Andy Lutomirski, Thomas Gleixner, Ingo Molnar,
Borislav Petkov, Dave Hansen, H. Peter Anvin, K. Y. Srinivasan,
Haiyang Zhang, Wei Liu, Dexuan Cui, Peter Zijlstra, Will Deacon,
Boqun Feng, Waiman Long, Jiri Kosina, Josh Poimboeuf, Pawan Gupta,
Boris Ostrovsky, xen-devel, Ajay Kaher, Alexey Makhalov,
Broadcom internal kernel review list, Russell King,
Catalin Marinas, Huacai Chen, WANG Xuerui, Madhavan Srinivasan,
Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Juri Lelli, Vincent Guittot, Dietmar Eggemann, Steven Rostedt,
Ben Segall, Mel Gorman, Valentin Schneider, linux-arm-kernel,
Paolo Bonzini, Vitaly Kuznetsov, Stefano Stabellini,
Oleksandr Tyshchenko, Daniel Lezcano
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
--
2.51.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 05/14] paravirt: remove asm/paravirt_api_clock.h
2025-09-11 6:34 [PATCH 00/14] paravirt: cleanup and reorg Juergen Gross
@ 2025-09-11 6:34 ` Juergen Gross
2025-09-11 6:34 ` [PATCH 06/14] sched: move clock related paravirt code to kernel/sched Juergen Gross
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Juergen Gross @ 2025-09-11 6:34 UTC (permalink / raw)
To: linux-kernel, x86, virtualization, loongarch, linuxppc-dev,
linux-riscv
Cc: Juergen Gross, Ajay Kaher, Alexey Makhalov,
Broadcom internal kernel review list, Russell King,
Catalin Marinas, Will Deacon, Huacai Chen, WANG Xuerui,
Madhavan Srinivasan, Michael Ellerman, Nicholas Piggin,
Christophe Leroy, Paul Walmsley, Palmer Dabbelt, Albert Ou,
Alexandre Ghiti, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Peter Zijlstra, Juri Lelli,
Vincent Guittot, Dietmar Eggemann, Steven Rostedt, Ben Segall,
Mel Gorman, Valentin Schneider, linux-arm-kernel
All architectures supporting CONFIG_PARAVIRT share the same contents
of asm/paravirt_api_clock.h:
#include <asm/paravirt.h>
So remove all incarnations of asm/paravirt_api_clock.h and remove the
only place where it is included, as there asm/paravirt.h is included
anyway.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/arm/include/asm/paravirt_api_clock.h | 1 -
arch/arm64/include/asm/paravirt_api_clock.h | 1 -
arch/loongarch/include/asm/paravirt_api_clock.h | 1 -
arch/powerpc/include/asm/paravirt_api_clock.h | 2 --
arch/riscv/include/asm/paravirt_api_clock.h | 1 -
arch/x86/include/asm/paravirt_api_clock.h | 1 -
kernel/sched/sched.h | 1 -
7 files changed, 8 deletions(-)
delete mode 100644 arch/arm/include/asm/paravirt_api_clock.h
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
diff --git a/arch/arm/include/asm/paravirt_api_clock.h b/arch/arm/include/asm/paravirt_api_clock.h
deleted file mode 100644
index 65ac7cee0dad..000000000000
--- a/arch/arm/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm/paravirt.h>
diff --git a/arch/arm64/include/asm/paravirt_api_clock.h b/arch/arm64/include/asm/paravirt_api_clock.h
deleted file mode 100644
index 65ac7cee0dad..000000000000
--- a/arch/arm64/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm/paravirt.h>
diff --git a/arch/loongarch/include/asm/paravirt_api_clock.h b/arch/loongarch/include/asm/paravirt_api_clock.h
deleted file mode 100644
index 65ac7cee0dad..000000000000
--- a/arch/loongarch/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm/paravirt.h>
diff --git a/arch/powerpc/include/asm/paravirt_api_clock.h b/arch/powerpc/include/asm/paravirt_api_clock.h
deleted file mode 100644
index d25ca7ac57c7..000000000000
--- a/arch/powerpc/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1,2 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <asm/paravirt.h>
diff --git a/arch/riscv/include/asm/paravirt_api_clock.h b/arch/riscv/include/asm/paravirt_api_clock.h
deleted file mode 100644
index 65ac7cee0dad..000000000000
--- a/arch/riscv/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm/paravirt.h>
diff --git a/arch/x86/include/asm/paravirt_api_clock.h b/arch/x86/include/asm/paravirt_api_clock.h
deleted file mode 100644
index 65ac7cee0dad..000000000000
--- a/arch/x86/include/asm/paravirt_api_clock.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <asm/paravirt.h>
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index be9745d104f7..6442441b46d7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -84,7 +84,6 @@ struct cpuidle_state;
#ifdef CONFIG_PARAVIRT
# include <asm/paravirt.h>
-# include <asm/paravirt_api_clock.h>
#endif
#include <asm/barrier.h>
--
2.51.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 06/14] sched: move clock related paravirt code to kernel/sched
2025-09-11 6:34 [PATCH 00/14] paravirt: cleanup and reorg Juergen Gross
2025-09-11 6:34 ` [PATCH 05/14] paravirt: remove asm/paravirt_api_clock.h Juergen Gross
@ 2025-09-11 6:34 ` Juergen Gross
2025-09-11 7:48 ` [PATCH 00/14] paravirt: cleanup and reorg Peter Zijlstra
2026-02-20 4:10 ` patchwork-bot+linux-riscv
3 siblings, 0 replies; 6+ messages in thread
From: Juergen Gross @ 2025-09-11 6:34 UTC (permalink / raw)
To: linux-kernel, x86, virtualization, loongarch, linuxppc-dev,
linux-riscv, kvm
Cc: Juergen Gross, Ajay Kaher, Alexey Makhalov,
Broadcom internal kernel review list, Russell King,
Catalin Marinas, Will Deacon, Huacai Chen, WANG Xuerui,
Madhavan Srinivasan, Michael Ellerman, Nicholas Piggin,
Christophe Leroy, Paul Walmsley, Palmer Dabbelt, Albert Ou,
Alexandre Ghiti, Thomas Gleixner, Ingo Molnar, Borislav Petkov,
Dave Hansen, H. Peter Anvin, Paolo Bonzini, Vitaly Kuznetsov,
Stefano Stabellini, Oleksandr Tyshchenko, Peter Zijlstra,
Juri Lelli, Vincent Guittot, Dietmar Eggemann, Steven Rostedt,
Ben Segall, Mel Gorman, Valentin Schneider, linux-arm-kernel,
xen-devel
Paravirt clock related functions are available in multiple archs.
In order to share the common parts, move the common static keys
to kernel/sched/ and remove them from the arch specific files.
Make a common paravirt_steal_clock() implementation available in
kernel/sched/cputime.c, guarding it with a new config option
CONFIG_HAVE_PV_STEAL_CLOCK_GEN, which can be selectd by an arch
in case it wants to use that common variant.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/Kconfig | 3 +++
arch/arm/include/asm/paravirt.h | 4 ----
arch/arm/kernel/paravirt.c | 3 ---
arch/arm64/include/asm/paravirt.h | 4 ----
arch/arm64/kernel/paravirt.c | 4 +---
arch/loongarch/include/asm/paravirt.h | 3 ---
arch/loongarch/kernel/paravirt.c | 3 +--
arch/powerpc/include/asm/paravirt.h | 3 ---
arch/powerpc/platforms/pseries/setup.c | 4 +---
arch/riscv/include/asm/paravirt.h | 4 ----
arch/riscv/kernel/paravirt.c | 4 +---
arch/x86/include/asm/paravirt.h | 4 ----
arch/x86/kernel/cpu/vmware.c | 1 +
arch/x86/kernel/kvm.c | 1 +
arch/x86/kernel/paravirt.c | 3 ---
drivers/xen/time.c | 1 +
include/linux/sched/cputime.h | 18 ++++++++++++++++++
kernel/sched/core.c | 5 +++++
kernel/sched/cputime.c | 13 +++++++++++++
kernel/sched/sched.h | 2 +-
20 files changed, 47 insertions(+), 40 deletions(-)
diff --git a/arch/Kconfig b/arch/Kconfig
index d1b4ffd6e085..7921be052472 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -1003,6 +1003,9 @@ config HAVE_IRQ_TIME_ACCOUNTING
Archs need to ensure they use a high enough resolution clock to
support irq time accounting and then call enable_sched_clock_irqtime().
+config HAVE_PV_STEAL_CLOCK_GEN
+ bool
+
config HAVE_MOVE_PUD
bool
help
diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h
index 95d5b0d625cd..69da4bdcf856 100644
--- a/arch/arm/include/asm/paravirt.h
+++ b/arch/arm/include/asm/paravirt.h
@@ -5,10 +5,6 @@
#ifdef CONFIG_PARAVIRT
#include <linux/static_call_types.h>
-struct static_key;
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
-
u64 dummy_steal_clock(int cpu);
DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c
index 7dd9806369fb..3895a5578852 100644
--- a/arch/arm/kernel/paravirt.c
+++ b/arch/arm/kernel/paravirt.c
@@ -12,9 +12,6 @@
#include <linux/static_call.h>
#include <asm/paravirt.h>
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
-
static u64 native_steal_clock(int cpu)
{
return 0;
diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h
index 9aa193e0e8f2..c9f7590baacb 100644
--- a/arch/arm64/include/asm/paravirt.h
+++ b/arch/arm64/include/asm/paravirt.h
@@ -5,10 +5,6 @@
#ifdef CONFIG_PARAVIRT
#include <linux/static_call_types.h>
-struct static_key;
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
-
u64 dummy_steal_clock(int cpu);
DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c
index aa718d6a9274..943b60ce12f4 100644
--- a/arch/arm64/kernel/paravirt.c
+++ b/arch/arm64/kernel/paravirt.c
@@ -19,14 +19,12 @@
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/static_call.h>
+#include <linux/sched/cputime.h>
#include <asm/paravirt.h>
#include <asm/pvclock-abi.h>
#include <asm/smp_plat.h>
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
-
static u64 native_steal_clock(int cpu)
{
return 0;
diff --git a/arch/loongarch/include/asm/paravirt.h b/arch/loongarch/include/asm/paravirt.h
index 3f4323603e6a..d219ea0d98ac 100644
--- a/arch/loongarch/include/asm/paravirt.h
+++ b/arch/loongarch/include/asm/paravirt.h
@@ -5,9 +5,6 @@
#ifdef CONFIG_PARAVIRT
#include <linux/static_call_types.h>
-struct static_key;
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
u64 dummy_steal_clock(int cpu);
DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
diff --git a/arch/loongarch/kernel/paravirt.c b/arch/loongarch/kernel/paravirt.c
index b1b51f920b23..8caaa94fed1a 100644
--- a/arch/loongarch/kernel/paravirt.c
+++ b/arch/loongarch/kernel/paravirt.c
@@ -6,11 +6,10 @@
#include <linux/kvm_para.h>
#include <linux/reboot.h>
#include <linux/static_call.h>
+#include <linux/sched/cputime.h>
#include <asm/paravirt.h>
static int has_steal_clock;
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
DEFINE_STATIC_KEY_FALSE(virt_spin_lock_key);
diff --git a/arch/powerpc/include/asm/paravirt.h b/arch/powerpc/include/asm/paravirt.h
index b78b82d66057..92343a23ad15 100644
--- a/arch/powerpc/include/asm/paravirt.h
+++ b/arch/powerpc/include/asm/paravirt.h
@@ -23,9 +23,6 @@ static inline bool is_shared_processor(void)
}
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
-
u64 pseries_paravirt_steal_clock(int cpu);
static inline u64 paravirt_steal_clock(int cpu)
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index b10a25325238..50b26ed8432d 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -42,6 +42,7 @@
#include <linux/memblock.h>
#include <linux/swiotlb.h>
#include <linux/seq_buf.h>
+#include <linux/sched/cputime.h>
#include <asm/mmu.h>
#include <asm/processor.h>
@@ -83,9 +84,6 @@ DEFINE_STATIC_KEY_FALSE(shared_processor);
EXPORT_SYMBOL(shared_processor);
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
-
static bool steal_acc = true;
static int __init parse_no_stealacc(char *arg)
{
diff --git a/arch/riscv/include/asm/paravirt.h b/arch/riscv/include/asm/paravirt.h
index c0abde70fc2c..17e5e39c72c0 100644
--- a/arch/riscv/include/asm/paravirt.h
+++ b/arch/riscv/include/asm/paravirt.h
@@ -5,10 +5,6 @@
#ifdef CONFIG_PARAVIRT
#include <linux/static_call_types.h>
-struct static_key;
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
-
u64 dummy_steal_clock(int cpu);
DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
diff --git a/arch/riscv/kernel/paravirt.c b/arch/riscv/kernel/paravirt.c
index fa6b0339a65d..d3c334f16172 100644
--- a/arch/riscv/kernel/paravirt.c
+++ b/arch/riscv/kernel/paravirt.c
@@ -16,15 +16,13 @@
#include <linux/printk.h>
#include <linux/static_call.h>
#include <linux/types.h>
+#include <linux/sched/cputime.h>
#include <asm/barrier.h>
#include <asm/page.h>
#include <asm/paravirt.h>
#include <asm/sbi.h>
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
-
static u64 native_steal_clock(int cpu)
{
return 0;
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 0d1e611f619c..491cb7e037bf 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -34,10 +34,6 @@ static __always_inline u64 paravirt_sched_clock(void)
return static_call(pv_sched_clock)();
}
-struct static_key;
-extern struct static_key paravirt_steal_enabled;
-extern struct static_key paravirt_steal_rq_enabled;
-
__visible void __native_queued_spin_unlock(struct qspinlock *lock);
bool pv_is_native_spin_unlock(void);
__visible bool __native_vcpu_is_preempted(long cpu);
diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c
index cb3f900c46fc..a3e6936839b1 100644
--- a/arch/x86/kernel/cpu/vmware.c
+++ b/arch/x86/kernel/cpu/vmware.c
@@ -29,6 +29,7 @@
#include <linux/efi.h>
#include <linux/reboot.h>
#include <linux/static_call.h>
+#include <linux/sched/cputime.h>
#include <asm/div64.h>
#include <asm/x86_init.h>
#include <asm/hypervisor.h>
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 8ae750cde0c6..a23211eaaeed 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -29,6 +29,7 @@
#include <linux/syscore_ops.h>
#include <linux/cc_platform.h>
#include <linux/efi.h>
+#include <linux/sched/cputime.h>
#include <asm/timer.h>
#include <asm/cpu.h>
#include <asm/traps.h>
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index ab3e172dcc69..a3ba4747be1c 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -60,9 +60,6 @@ void __init native_pv_lock_init(void)
static_branch_enable(&virt_spin_lock_key);
}
-struct static_key paravirt_steal_enabled;
-struct static_key paravirt_steal_rq_enabled;
-
static u64 native_steal_clock(int cpu)
{
return 0;
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 5683383d2305..d360ded2ef39 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -8,6 +8,7 @@
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/static_call.h>
+#include <linux/sched/cputime.h>
#include <asm/paravirt.h>
#include <asm/xen/hypervisor.h>
diff --git a/include/linux/sched/cputime.h b/include/linux/sched/cputime.h
index 5f8fd5b24a2e..e90efaf6d26e 100644
--- a/include/linux/sched/cputime.h
+++ b/include/linux/sched/cputime.h
@@ -2,6 +2,7 @@
#ifndef _LINUX_SCHED_CPUTIME_H
#define _LINUX_SCHED_CPUTIME_H
+#include <linux/static_call_types.h>
#include <linux/sched/signal.h>
/*
@@ -180,4 +181,21 @@ static inline void prev_cputime_init(struct prev_cputime *prev)
extern unsigned long long
task_sched_runtime(struct task_struct *task);
+#ifdef CONFIG_PARAVIRT
+struct static_key;
+extern struct static_key paravirt_steal_enabled;
+extern struct static_key paravirt_steal_rq_enabled;
+
+#ifdef CONFIG_HAVE_PV_STEAL_CLOCK_GEN
+u64 dummy_steal_clock(int cpu);
+
+DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock);
+
+static inline u64 paravirt_steal_clock(int cpu)
+{
+ return static_call(pv_steal_clock)(cpu);
+}
+#endif
+#endif
+
#endif /* _LINUX_SCHED_CPUTIME_H */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index be00629f0ba4..e723226e4e11 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -767,6 +767,11 @@ struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
* RQ-clock updating methods:
*/
+/* Use CONFIG_PARAVIRT as this will avoid more #ifdef in arch code. */
+#ifdef CONFIG_PARAVIRT
+struct static_key paravirt_steal_rq_enabled;
+#endif
+
static void update_rq_clock_task(struct rq *rq, s64 delta)
{
/*
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 7097de2c8cda..ed8f71e08047 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -251,6 +251,19 @@ void __account_forceidle_time(struct task_struct *p, u64 delta)
* ticks are not redelivered later. Due to that, this function may on
* occasion account more time than the calling functions think elapsed.
*/
+#ifdef CONFIG_PARAVIRT
+struct static_key paravirt_steal_enabled;
+
+#ifdef CONFIG_HAVE_PV_STEAL_CLOCK_GEN
+static u64 native_steal_clock(int cpu)
+{
+ return 0;
+}
+
+DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock);
+#endif
+#endif
+
static __always_inline u64 steal_account_process_time(u64 maxtime)
{
#ifdef CONFIG_PARAVIRT
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 6442441b46d7..fdf3021bdf7d 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -82,7 +82,7 @@ struct rt_rq;
struct sched_group;
struct cpuidle_state;
-#ifdef CONFIG_PARAVIRT
+#if defined(CONFIG_PARAVIRT) && !defined(CONFIG_HAVE_PV_STEAL_CLOCK_GEN)
# include <asm/paravirt.h>
#endif
--
2.51.0
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 00/14] paravirt: cleanup and reorg
2025-09-11 6:34 [PATCH 00/14] paravirt: cleanup and reorg Juergen Gross
2025-09-11 6:34 ` [PATCH 05/14] paravirt: remove asm/paravirt_api_clock.h Juergen Gross
2025-09-11 6:34 ` [PATCH 06/14] sched: move clock related paravirt code to kernel/sched Juergen Gross
@ 2025-09-11 7:48 ` Peter Zijlstra
2025-09-11 8:00 ` Jürgen Groß
2026-02-20 4:10 ` patchwork-bot+linux-riscv
3 siblings, 1 reply; 6+ messages in thread
From: Peter Zijlstra @ 2025-09-11 7:48 UTC (permalink / raw)
To: Juergen Gross
Cc: linux-kernel, x86, linux-hyperv, virtualization, loongarch,
linuxppc-dev, linux-riscv, kvm, Andy Lutomirski, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
K. Y. Srinivasan, Haiyang Zhang, Wei Liu, Dexuan Cui, Will Deacon,
Boqun Feng, Waiman Long, Jiri Kosina, Josh Poimboeuf, Pawan Gupta,
Boris Ostrovsky, xen-devel, Ajay Kaher, Alexey Makhalov,
Broadcom internal kernel review list, Russell King,
Catalin Marinas, Huacai Chen, WANG Xuerui, Madhavan Srinivasan,
Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Juri Lelli, Vincent Guittot, Dietmar Eggemann, Steven Rostedt,
Ben Segall, Mel Gorman, Valentin Schneider, linux-arm-kernel,
Paolo Bonzini, Vitaly Kuznetsov, Stefano Stabellini,
Oleksandr Tyshchenko, Daniel Lezcano
On Thu, Sep 11, 2025 at 08:34:19AM +0200, 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 6-12 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
With the note that tip typically likes a capital after the prefix, like:
x86/paravirt: Remove unneeded includes of paravirt.h
For 1-12:
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Now, as to the last two, I'm not sure. Leaking those macros out of PV
isn't particularly nice, then again, not the end of the world either.
Just not sure.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 00/14] paravirt: cleanup and reorg
2025-09-11 7:48 ` [PATCH 00/14] paravirt: cleanup and reorg Peter Zijlstra
@ 2025-09-11 8:00 ` Jürgen Groß
0 siblings, 0 replies; 6+ messages in thread
From: Jürgen Groß @ 2025-09-11 8:00 UTC (permalink / raw)
To: Peter Zijlstra
Cc: linux-kernel, x86, linux-hyperv, virtualization, loongarch,
linuxppc-dev, linux-riscv, kvm, Andy Lutomirski, Thomas Gleixner,
Ingo Molnar, Borislav Petkov, Dave Hansen, H. Peter Anvin,
K. Y. Srinivasan, Haiyang Zhang, Wei Liu, Dexuan Cui, Will Deacon,
Boqun Feng, Waiman Long, Jiri Kosina, Josh Poimboeuf, Pawan Gupta,
Boris Ostrovsky, xen-devel, Ajay Kaher, Alexey Makhalov,
Broadcom internal kernel review list, Russell King,
Catalin Marinas, Huacai Chen, WANG Xuerui, Madhavan Srinivasan,
Michael Ellerman, Nicholas Piggin, Christophe Leroy,
Paul Walmsley, Palmer Dabbelt, Albert Ou, Alexandre Ghiti,
Juri Lelli, Vincent Guittot, Dietmar Eggemann, Steven Rostedt,
Ben Segall, Mel Gorman, Valentin Schneider, linux-arm-kernel,
Paolo Bonzini, Vitaly Kuznetsov, Stefano Stabellini,
Oleksandr Tyshchenko, Daniel Lezcano
[-- Attachment #1.1.1: Type: text/plain, Size: 3443 bytes --]
On 11.09.25 09:48, Peter Zijlstra wrote:
> On Thu, Sep 11, 2025 at 08:34:19AM +0200, 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 6-12 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
>
> With the note that tip typically likes a capital after the prefix, like:
>
> x86/paravirt: Remove unneeded includes of paravirt.h
Noted, thanks.
>
> For 1-12:
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
>
>
> Now, as to the last two, I'm not sure. Leaking those macros out of PV
> isn't particularly nice, then again, not the end of the world either.
> Just not sure.
Yes, that's why I didn't continue with all of the other potential movement of
paravirt functions. I want some feedback first. :-)
Its a tradeoff between having functions with / without paravirt in one file
against hiding the paravirt stuff from "normal" readers (not writers, as those
probably need to touch the paravirt variant, too).
BTW, I think the macro leaking isn't the main problem. There are other macros
leaking already.
Juergen
[-- Attachment #1.1.2: OpenPGP public key --]
[-- Type: application/pgp-keys, Size: 3743 bytes --]
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 00/14] paravirt: cleanup and reorg
2025-09-11 6:34 [PATCH 00/14] paravirt: cleanup and reorg Juergen Gross
` (2 preceding siblings ...)
2025-09-11 7:48 ` [PATCH 00/14] paravirt: cleanup and reorg Peter Zijlstra
@ 2026-02-20 4:10 ` patchwork-bot+linux-riscv
3 siblings, 0 replies; 6+ messages in thread
From: patchwork-bot+linux-riscv @ 2026-02-20 4:10 UTC (permalink / raw)
To: =?utf-8?b?SsO8cmdlbiBHcm/DnyA8amdyb3NzQHN1c2UuY29tPg==?=
Cc: linux-riscv, linux-kernel, x86, linux-hyperv, virtualization,
loongarch, linuxppc-dev, kvm, luto, tglx, mingo, bp, dave.hansen,
hpa, kys, haiyangz, wei.liu, decui, peterz, will, boqun.feng,
longman, jikos, jpoimboe, pawan.kumar.gupta, boris.ostrovsky,
xen-devel, ajay.kaher, alexey.makhalov, bcm-kernel-feedback-list,
linux, catalin.marinas, chenhuacai, kernel, maddy, mpe, npiggin,
christophe.leroy, paul.walmsley, palmer, aou, alex, juri.lelli,
vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman,
vschneid, linux-arm-kernel, pbonzini, vkuznets, sstabellini,
oleksandr_tyshchenko, daniel.lezcano
Hello:
This series was applied to riscv/linux.git (fixes)
by Borislav Petkov (AMD) <bp@alien8.de>:
On Thu, 11 Sep 2025 08:34:19 +0200 you 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.
>
> [...]
Here is the summary with links:
- [05/14] paravirt: remove asm/paravirt_api_clock.h
https://git.kernel.org/riscv/c/68b10fd40d49
- [06/14] sched: move clock related paravirt code to kernel/sched
(no matching commit)
- [10/14] riscv/paravirt: use common code for paravirt_steal_clock()
https://git.kernel.org/riscv/c/ee9ffcf99f07
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-02-20 4:11 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2025-09-11 6:34 [PATCH 00/14] paravirt: cleanup and reorg Juergen Gross
2025-09-11 6:34 ` [PATCH 05/14] paravirt: remove asm/paravirt_api_clock.h Juergen Gross
2025-09-11 6:34 ` [PATCH 06/14] sched: move clock related paravirt code to kernel/sched Juergen Gross
2025-09-11 7:48 ` [PATCH 00/14] paravirt: cleanup and reorg Peter Zijlstra
2025-09-11 8:00 ` Jürgen Groß
2026-02-20 4:10 ` patchwork-bot+linux-riscv
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