RE: [PATCH v3 06/15] x86/paravirt: switch time pvops functions to use static_call()
From: Michael Kelley <hidden>
Date: 2020-12-17 17:32:43
Also in:
kvm, lkml, virtualization, xen-devel
From: Juergen Gross <jgross@suse.com> Sent: Thursday, December 17, 2020 1:31 AM
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. Due to include hell this requires to split out the time interfaces into a new header file. Signed-off-by: Juergen Gross <jgross@suse.com> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/mshyperv.h | 11 -------- arch/x86/include/asm/paravirt.h | 14 ---------- arch/x86/include/asm/paravirt_time.h | 38 +++++++++++++++++++++++++++ arch/x86/include/asm/paravirt_types.h | 6 ----- arch/x86/kernel/cpu/vmware.c | 5 ++-- arch/x86/kernel/kvm.c | 3 ++- arch/x86/kernel/kvmclock.c | 3 ++- arch/x86/kernel/paravirt.c | 16 ++++++++--- arch/x86/kernel/tsc.c | 3 ++- arch/x86/xen/time.c | 12 ++++----- drivers/clocksource/hyperv_timer.c | 5 ++-- drivers/xen/time.c | 3 ++- kernel/sched/sched.h | 1 + 14 files changed, 71 insertions(+), 50 deletions(-) create mode 100644 arch/x86/include/asm/paravirt_time.h
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diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h index ffc289992d1b..45942d420626 100644 --- a/arch/x86/include/asm/mshyperv.h +++ b/arch/x86/include/asm/mshyperv.h@@ -56,17 +56,6 @@ typedef int (*hyperv_fill_flush_list_func)( #define hv_get_raw_timer() rdtsc_ordered() #define hv_get_vector() HYPERVISOR_CALLBACK_VECTOR -/* - * Reference to pv_ops must be inline so objtool - * detection of noinstr violations can work correctly. - */ -static __always_inline void hv_setup_sched_clock(void *sched_clock) -{ -#ifdef CONFIG_PARAVIRT - pv_ops.time.sched_clock = sched_clock; -#endif -} - void hyperv_vector_handler(struct pt_regs *regs); static inline void hv_enable_stimer0_percpu_irq(int irq) {}
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diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c index ba04cb381cd3..1ed79993fc50 100644 --- a/drivers/clocksource/hyperv_timer.c +++ b/drivers/clocksource/hyperv_timer.c@@ -21,6 +21,7 @@ #include <clocksource/hyperv_timer.h> #include <asm/hyperv-tlfs.h> #include <asm/mshyperv.h> +#include <asm/paravirt_time.h> static struct clock_event_device __percpu *hv_clock_event; static u64 hv_sched_clock_offset __ro_after_init;@@ -445,7 +446,7 @@ static bool __init hv_init_tsc_clocksource(void) clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100); hv_sched_clock_offset = hv_read_reference_counter(); - hv_setup_sched_clock(read_hv_sched_clock_tsc); + paravirt_set_sched_clock(read_hv_sched_clock_tsc); return true; }@@ -470,6 +471,6 @@ void __init hv_init_clocksource(void) clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100); hv_sched_clock_offset = hv_read_reference_counter(); - hv_setup_sched_clock(read_hv_sched_clock_msr); + static_call_update(pv_sched_clock, read_hv_sched_clock_msr); } EXPORT_SYMBOL_GPL(hv_init_clocksource);
These Hyper-V changes are problematic as we want to keep hyperv_timer.c architecture independent. While only the code for x86/x64 is currently accepted upstream, code for ARM64 support is in progress. So we need to use hv_setup_sched_clock() in hyperv_timer.c, and have the per-arch implementation in mshyperv.h. Michael