Juergen Gross
2021-Mar-09 13:48 UTC
[PATCH v6 02/12] x86/paravirt: switch time pvops functions to use static_call()
The time pvops functions are the only ones left which might be used in 32-bit mode and which return a 64-bit value. Switch them to use the static_call() mechanism instead of pvops, as this allows quite some simplification of the pvops implementation. Signed-off-by: Juergen Gross <jgross at suse.com> Acked-by: Peter Zijlstra (Intel) <peterz at infradead.org> --- V4: - drop paravirt_time.h again - don't move Hyper-V code (Michael Kelley) V5: - drop no longer needed Hyper-V modification (Michael Kelley) - switch Arm and Arm64 to static_call(), too (kernel test robot) V6: - factor out common parts in Xen pv/pvh initialization (Boris Petkov) --- arch/arm/include/asm/paravirt.h | 14 +++++--------- arch/arm/kernel/paravirt.c | 9 +++++++-- arch/arm64/include/asm/paravirt.h | 14 +++++--------- arch/arm64/kernel/paravirt.c | 13 +++++++++---- arch/x86/Kconfig | 1 + arch/x86/include/asm/mshyperv.h | 2 +- arch/x86/include/asm/paravirt.h | 17 ++++++++++++++--- arch/x86/include/asm/paravirt_types.h | 6 ------ arch/x86/kernel/cpu/vmware.c | 5 +++-- arch/x86/kernel/kvm.c | 2 +- arch/x86/kernel/kvmclock.c | 2 +- arch/x86/kernel/paravirt.c | 16 ++++++++++++---- arch/x86/kernel/tsc.c | 2 +- arch/x86/xen/time.c | 26 +++++++++++++------------- drivers/xen/time.c | 3 ++- 15 files changed, 75 insertions(+), 57 deletions(-) diff --git a/arch/arm/include/asm/paravirt.h b/arch/arm/include/asm/paravirt.h index cdbf02d9c1d4..95d5b0d625cd 100644 --- a/arch/arm/include/asm/paravirt.h +++ b/arch/arm/include/asm/paravirt.h @@ -3,23 +3,19 @@ #define _ASM_ARM_PARAVIRT_H #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; -struct pv_time_ops { - unsigned long long (*steal_clock)(int cpu); -}; - -struct paravirt_patch_template { - struct pv_time_ops time; -}; +u64 dummy_steal_clock(int cpu); -extern struct paravirt_patch_template pv_ops; +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock); static inline u64 paravirt_steal_clock(int cpu) { - return pv_ops.time.steal_clock(cpu); + return static_call(pv_steal_clock)(cpu); } #endif diff --git a/arch/arm/kernel/paravirt.c b/arch/arm/kernel/paravirt.c index 4cfed91fe256..7dd9806369fb 100644 --- a/arch/arm/kernel/paravirt.c +++ b/arch/arm/kernel/paravirt.c @@ -9,10 +9,15 @@ #include <linux/export.h> #include <linux/jump_label.h> #include <linux/types.h> +#include <linux/static_call.h> #include <asm/paravirt.h> struct static_key paravirt_steal_enabled; struct static_key paravirt_steal_rq_enabled; -struct paravirt_patch_template pv_ops; -EXPORT_SYMBOL_GPL(pv_ops); +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); diff --git a/arch/arm64/include/asm/paravirt.h b/arch/arm64/include/asm/paravirt.h index cf3a0fd7c1a7..9aa193e0e8f2 100644 --- a/arch/arm64/include/asm/paravirt.h +++ b/arch/arm64/include/asm/paravirt.h @@ -3,23 +3,19 @@ #define _ASM_ARM64_PARAVIRT_H #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; -struct pv_time_ops { - unsigned long long (*steal_clock)(int cpu); -}; - -struct paravirt_patch_template { - struct pv_time_ops time; -}; +u64 dummy_steal_clock(int cpu); -extern struct paravirt_patch_template pv_ops; +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock); static inline u64 paravirt_steal_clock(int cpu) { - return pv_ops.time.steal_clock(cpu); + return static_call(pv_steal_clock)(cpu); } int __init pv_time_init(void); diff --git a/arch/arm64/kernel/paravirt.c b/arch/arm64/kernel/paravirt.c index c07d7a034941..75fed4460407 100644 --- a/arch/arm64/kernel/paravirt.c +++ b/arch/arm64/kernel/paravirt.c @@ -18,6 +18,7 @@ #include <linux/reboot.h> #include <linux/slab.h> #include <linux/types.h> +#include <linux/static_call.h> #include <asm/paravirt.h> #include <asm/pvclock-abi.h> @@ -26,8 +27,12 @@ struct static_key paravirt_steal_enabled; struct static_key paravirt_steal_rq_enabled; -struct paravirt_patch_template pv_ops; -EXPORT_SYMBOL_GPL(pv_ops); +static u64 native_steal_clock(int cpu) +{ + return 0; +} + +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); struct pv_time_stolen_time_region { struct pvclock_vcpu_stolen_time *kaddr; @@ -45,7 +50,7 @@ static int __init parse_no_stealacc(char *arg) early_param("no-steal-acc", parse_no_stealacc); /* return stolen time in ns by asking the hypervisor */ -static u64 pv_steal_clock(int cpu) +static u64 para_steal_clock(int cpu) { struct pv_time_stolen_time_region *reg; @@ -150,7 +155,7 @@ int __init pv_time_init(void) if (ret) return ret; - pv_ops.time.steal_clock = pv_steal_clock; + static_call_update(pv_steal_clock, para_steal_clock); static_key_slow_inc(¶virt_steal_enabled); if (steal_acc) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2792879d398e..107acc403b3b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -777,6 +777,7 @@ if HYPERVISOR_GUEST config PARAVIRT bool "Enable paravirtualization code" + depends on HAVE_STATIC_CALL help This changes the kernel so it can modify itself when it is run under a hypervisor, potentially improving performance significantly diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index ccf60a809a17..e7be720062a8 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h @@ -63,7 +63,7 @@ typedef int (*hyperv_fill_flush_list_func)( static __always_inline void hv_setup_sched_clock(void *sched_clock) { #ifdef CONFIG_PARAVIRT - pv_ops.time.sched_clock = sched_clock; + paravirt_set_sched_clock(sched_clock); #endif } diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 4abf110e2243..1e45b46fae84 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -15,11 +15,22 @@ #include <linux/bug.h> #include <linux/types.h> #include <linux/cpumask.h> +#include <linux/static_call_types.h> #include <asm/frame.h> -static inline unsigned long long paravirt_sched_clock(void) +u64 dummy_steal_clock(int cpu); +u64 dummy_sched_clock(void); + +DECLARE_STATIC_CALL(pv_steal_clock, dummy_steal_clock); +DECLARE_STATIC_CALL(pv_sched_clock, dummy_sched_clock); + +extern bool paravirt_using_native_sched_clock; + +void paravirt_set_sched_clock(u64 (*func)(void)); + +static inline u64 paravirt_sched_clock(void) { - return PVOP_CALL0(unsigned long long, time.sched_clock); + return static_call(pv_sched_clock)(); } struct static_key; @@ -33,7 +44,7 @@ bool pv_is_native_vcpu_is_preempted(void); static inline u64 paravirt_steal_clock(int cpu) { - return PVOP_CALL1(u64, time.steal_clock, cpu); + return static_call(pv_steal_clock)(cpu); } /* The paravirtualized I/O functions */ diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index de87087d3bde..1fff349e4792 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -95,11 +95,6 @@ struct pv_lazy_ops { } __no_randomize_layout; #endif -struct pv_time_ops { - unsigned long long (*sched_clock)(void); - unsigned long long (*steal_clock)(int cpu); -} __no_randomize_layout; - struct pv_cpu_ops { /* hooks for various privileged instructions */ void (*io_delay)(void); @@ -291,7 +286,6 @@ struct pv_lock_ops { * what to patch. */ struct paravirt_patch_template { struct pv_init_ops init; - struct pv_time_ops time; struct pv_cpu_ops cpu; struct pv_irq_ops irq; struct pv_mmu_ops mmu; diff --git a/arch/x86/kernel/cpu/vmware.c b/arch/x86/kernel/cpu/vmware.c index c6ede3b3d302..84fb8e3f3d1b 100644 --- a/arch/x86/kernel/cpu/vmware.c +++ b/arch/x86/kernel/cpu/vmware.c @@ -27,6 +27,7 @@ #include <linux/clocksource.h> #include <linux/cpu.h> #include <linux/reboot.h> +#include <linux/static_call.h> #include <asm/div64.h> #include <asm/x86_init.h> #include <asm/hypervisor.h> @@ -336,11 +337,11 @@ static void __init vmware_paravirt_ops_setup(void) vmware_cyc2ns_setup(); if (vmw_sched_clock) - pv_ops.time.sched_clock = vmware_sched_clock; + paravirt_set_sched_clock(vmware_sched_clock); if (vmware_is_stealclock_available()) { has_steal_clock = true; - pv_ops.time.steal_clock = vmware_steal_clock; + static_call_update(pv_steal_clock, vmware_steal_clock); /* We use reboot notifier only to disable steal clock */ register_reboot_notifier(&vmware_pv_reboot_nb); diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 5e78e01ca3b4..351ba99f6009 100644 --- a/arch/x86/kernel/kvm.c +++ b/arch/x86/kernel/kvm.c @@ -650,7 +650,7 @@ static void __init kvm_guest_init(void) if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) { has_steal_clock = 1; - pv_ops.time.steal_clock = kvm_steal_clock; + static_call_update(pv_steal_clock, kvm_steal_clock); } if (pv_tlb_flush_supported()) { diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index aa593743acf6..01e7c1839ace 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -106,7 +106,7 @@ static inline void kvm_sched_clock_init(bool stable) if (!stable) clear_sched_clock_stable(); kvm_sched_clock_offset = kvm_clock_read(); - pv_ops.time.sched_clock = kvm_sched_clock_read; + paravirt_set_sched_clock(kvm_sched_clock_read); pr_info("kvm-clock: using sched offset of %llu cycles", kvm_sched_clock_offset); diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index c60222ab8ab9..44e5b0fe28cb 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -14,6 +14,7 @@ #include <linux/highmem.h> #include <linux/kprobes.h> #include <linux/pgtable.h> +#include <linux/static_call.h> #include <asm/bug.h> #include <asm/paravirt.h> @@ -167,6 +168,17 @@ static u64 native_steal_clock(int cpu) return 0; } +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); +DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); + +bool paravirt_using_native_sched_clock = true; + +void paravirt_set_sched_clock(u64 (*func)(void)) +{ + static_call_update(pv_sched_clock, func); + paravirt_using_native_sched_clock = (func == native_sched_clock); +} + /* These are in entry.S */ extern void native_iret(void); @@ -272,10 +284,6 @@ struct paravirt_patch_template pv_ops = { /* Init ops. */ .init.patch = native_patch, - /* Time ops. */ - .time.sched_clock = native_sched_clock, - .time.steal_clock = native_steal_clock, - /* Cpu ops. */ .cpu.io_delay = native_io_delay, diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index f70dffc2771f..b6f7853d8077 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -254,7 +254,7 @@ unsigned long long sched_clock(void) bool using_native_sched_clock(void) { - return pv_ops.time.sched_clock == native_sched_clock; + return paravirt_using_native_sched_clock; } #else unsigned long long diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c index 91f5b330dcc6..d9c945ee1100 100644 --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -379,11 +379,6 @@ void xen_timer_resume(void) } } -static const struct pv_time_ops xen_time_ops __initconst = { - .sched_clock = xen_sched_clock, - .steal_clock = xen_steal_clock, -}; - static struct pvclock_vsyscall_time_info *xen_clock __read_mostly; static u64 xen_clock_value_saved; @@ -525,17 +520,24 @@ static void __init xen_time_init(void) pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); } -void __init xen_init_time_ops(void) +static void __init xen_init_time_common(void) { xen_sched_clock_offset = xen_clocksource_read(); - pv_ops.time = xen_time_ops; + static_call_update(pv_steal_clock, xen_steal_clock); + paravirt_set_sched_clock(xen_sched_clock); + + x86_platform.calibrate_tsc = xen_tsc_khz; + x86_platform.get_wallclock = xen_get_wallclock; +} + +void __init xen_init_time_ops(void) +{ + xen_init_time_common(); x86_init.timers.timer_init = xen_time_init; x86_init.timers.setup_percpu_clockev = x86_init_noop; x86_cpuinit.setup_percpu_clockev = x86_init_noop; - x86_platform.calibrate_tsc = xen_tsc_khz; - x86_platform.get_wallclock = xen_get_wallclock; /* Dom0 uses the native method to set the hardware RTC. */ if (!xen_initial_domain()) x86_platform.set_wallclock = xen_set_wallclock; @@ -569,13 +571,11 @@ void __init xen_hvm_init_time_ops(void) return; } - xen_sched_clock_offset = xen_clocksource_read(); - pv_ops.time = xen_time_ops; + xen_init_time_common(); + x86_init.timers.setup_percpu_clockev = xen_time_init; x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents; - x86_platform.calibrate_tsc = xen_tsc_khz; - x86_platform.get_wallclock = xen_get_wallclock; x86_platform.set_wallclock = xen_set_wallclock; } #endif diff --git a/drivers/xen/time.c b/drivers/xen/time.c index 108edbcbc040..152dd33bb223 100644 --- a/drivers/xen/time.c +++ b/drivers/xen/time.c @@ -7,6 +7,7 @@ #include <linux/math64.h> #include <linux/gfp.h> #include <linux/slab.h> +#include <linux/static_call.h> #include <asm/paravirt.h> #include <asm/xen/hypervisor.h> @@ -175,7 +176,7 @@ void __init xen_time_setup_guest(void) xen_runstate_remote = !HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_runstate_update_flag); - pv_ops.time.steal_clock = xen_steal_clock; + static_call_update(pv_steal_clock, xen_steal_clock); static_key_slow_inc(¶virt_steal_enabled); if (xen_runstate_remote) -- 2.26.2
Borislav Petkov
2021-Mar-09 18:57 UTC
[PATCH v6 02/12] x86/paravirt: switch time pvops functions to use static_call()
On Tue, Mar 09, 2021 at 02:48:03PM +0100, Juergen Gross wrote:> @@ -167,6 +168,17 @@ static u64 native_steal_clock(int cpu) > return 0; > } > > +DEFINE_STATIC_CALL(pv_steal_clock, native_steal_clock); > +DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); > + > +bool paravirt_using_native_sched_clock = true; > + > +void paravirt_set_sched_clock(u64 (*func)(void)) > +{ > + static_call_update(pv_sched_clock, func); > + paravirt_using_native_sched_clock = (func == native_sched_clock); > +}What's the point of this function if there's a global paravirt_using_native_sched_clock variable now? Looking how the bit of information whether native_sched_clock is used, is needed in tsc.c, it probably would be cleaner if you add a set_sched_clock_native(void); or so, to tsc.c instead and call that here and make that long var name a a shorter and static one in tsc.c instead. Hmm? -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette