[PATCH v6 02/12] x86/paravirt: switch time pvops functions to use static_call()
From: Juergen Gross <jgross@suse.com>
Date: 2021-03-09 13:49:28
Also in:
kvm, linux-arm-kernel, lkml, virtualization, xen-devel
Subsystem:
arm port, arm64 port (aarch64 architecture), hyper-v/azure core and drivers, kvm paravirt (kvm/paravirt), paravirt_ops interface, the rest, vmware hypervisor interface, x86 architecture (32-bit and 64-bit), xen hypervisor interface, xen hypervisor x86 · Maintainers:
Russell King, Catalin Marinas, Will Deacon, "K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Paolo Bonzini, Juergen Gross, Linus Torvalds, Ajay Kaher, Alexey Makhalov, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Stefano Stabellini
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@suse.com> Acked-by: Peter Zijlstra (Intel) <peterz@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