[PATCH v14 04/25] x86/kvmclock: Cleanup the code
From: Thomas Gleixner - Cleanup the mrs write for wall clock. The type casts to (int) are sloppy because the wrmsr parameters are u32 and aside of that wrmsrl() already provides the high/low split for free. - Remove the pointless get_cpu()/put_cpu() dance from various functions. Either they are called during early init where CPU is guaranteed to be 0 or they are already called from non preemptible context where smp_processor_id() can be used safely - Simplify the convoluted check for kvmclock in the init function. - Mark the parameter parsing function __init. No point in keeping it around. - Convert to pr_info() Signed-off-by: Thomas Gleixner Signed-off-by: Pavel Tatashin Acked-by: Paolo Bonzini --- arch/x86/kernel/kvmclock.c | 76 -- 1 file changed, 23 insertions(+), 53 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index cbf0a6b9217b..04d2f5e1d783 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -37,7 +37,7 @@ static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; static u64 kvm_sched_clock_offset; -static int parse_no_kvmclock(char *arg) +static int __init parse_no_kvmclock(char *arg) { kvmclock = 0; return 0; @@ -61,13 +61,9 @@ static struct pvclock_wall_clock wall_clock; static void kvm_get_wallclock(struct timespec64 *now) { struct pvclock_vcpu_time_info *vcpu_time; - int low, high; int cpu; - low = (int)slow_virt_to_phys(_clock); - high = ((u64)slow_virt_to_phys(_clock) >> 32); - - native_write_msr(msr_kvm_wall_clock, low, high); + wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(_clock)); cpu = get_cpu(); @@ -117,11 +113,11 @@ static inline void kvm_sched_clock_init(bool stable) kvm_sched_clock_offset = kvm_clock_read(); pv_time_ops.sched_clock = kvm_sched_clock_read; - printk(KERN_INFO "kvm-clock: using sched offset of %llu cycles\n", - kvm_sched_clock_offset); + pr_info("kvm-clock: using sched offset of %llu cycles", + kvm_sched_clock_offset); BUILD_BUG_ON(sizeof(kvm_sched_clock_offset) > -sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time)); + sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time)); } /* @@ -135,15 +131,7 @@ static inline void kvm_sched_clock_init(bool stable) */ static unsigned long kvm_get_tsc_khz(void) { - struct pvclock_vcpu_time_info *src; - int cpu; - unsigned long tsc_khz; - - cpu = get_cpu(); - src = _clock[cpu].pvti; - tsc_khz = pvclock_tsc_khz(src); - put_cpu(); - return tsc_khz; + return pvclock_tsc_khz(_clock[0].pvti); } static void kvm_get_preset_lpj(void) @@ -160,29 +148,27 @@ static void kvm_get_preset_lpj(void) bool kvm_check_and_clear_guest_paused(void) { - bool ret = false; struct pvclock_vcpu_time_info *src; - int cpu = smp_processor_id(); + bool ret = false; if (!hv_clock) return ret; - src = _clock[cpu].pvti; + src = _clock[smp_processor_id()].pvti; if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) { src->flags &= ~PVCLOCK_GUEST_STOPPED; pvclock_touch_watchdogs(); ret = true; } - return ret; } struct clocksource kvm_clock = { - .name = "kvm-clock", - .read = kvm_clock_get_cycles, - .rating = 400, - .mask = CLOCKSOURCE_MASK(64), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .name = "kvm-clock", + .read = kvm_clock_get_cycles, + .rating = 400, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; EXPORT_SYMBOL_GPL(kvm_clock); @@ -198,7 +184,7 @@ static void kvm_register_clock(char *txt) src = _clock[cpu].pvti; pa = slow_virt_to_phys(src) | 0x01ULL; wrmsrl(msr_kvm_system_time, pa); - pr_info("kvm-clock: cpu %d, msr %llx, %s\n", cpu, pa, txt); + pr_info("kvm-clock: cpu %d, msr %llx, %s", cpu, pa, txt); } static void kvm_save_sched_clock_state(void) @@ -243,20 +229,19 @@ static void kvm_shutdown(void) void __init kvmclock_init(void) { - struct pvclock_vcpu_time_info *vcpu_time; - int cpu; u8 flags; - if (!kvm_para_available()) + if (!kvm_para_available() || !kvmclock) return; - if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { + if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW; msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW; - } else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE))) + } else if (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) { return; + }
[PATCH v14 04/25] x86/kvmclock: Cleanup the code
From: Thomas Gleixner - Cleanup the mrs write for wall clock. The type casts to (int) are sloppy because the wrmsr parameters are u32 and aside of that wrmsrl() already provides the high/low split for free. - Remove the pointless get_cpu()/put_cpu() dance from various functions. Either they are called during early init where CPU is guaranteed to be 0 or they are already called from non preemptible context where smp_processor_id() can be used safely - Simplify the convoluted check for kvmclock in the init function. - Mark the parameter parsing function __init. No point in keeping it around. - Convert to pr_info() Signed-off-by: Thomas Gleixner Signed-off-by: Pavel Tatashin Acked-by: Paolo Bonzini --- arch/x86/kernel/kvmclock.c | 76 -- 1 file changed, 23 insertions(+), 53 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index cbf0a6b9217b..04d2f5e1d783 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -37,7 +37,7 @@ static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME; static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK; static u64 kvm_sched_clock_offset; -static int parse_no_kvmclock(char *arg) +static int __init parse_no_kvmclock(char *arg) { kvmclock = 0; return 0; @@ -61,13 +61,9 @@ static struct pvclock_wall_clock wall_clock; static void kvm_get_wallclock(struct timespec64 *now) { struct pvclock_vcpu_time_info *vcpu_time; - int low, high; int cpu; - low = (int)slow_virt_to_phys(_clock); - high = ((u64)slow_virt_to_phys(_clock) >> 32); - - native_write_msr(msr_kvm_wall_clock, low, high); + wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(_clock)); cpu = get_cpu(); @@ -117,11 +113,11 @@ static inline void kvm_sched_clock_init(bool stable) kvm_sched_clock_offset = kvm_clock_read(); pv_time_ops.sched_clock = kvm_sched_clock_read; - printk(KERN_INFO "kvm-clock: using sched offset of %llu cycles\n", - kvm_sched_clock_offset); + pr_info("kvm-clock: using sched offset of %llu cycles", + kvm_sched_clock_offset); BUILD_BUG_ON(sizeof(kvm_sched_clock_offset) > -sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time)); + sizeof(((struct pvclock_vcpu_time_info *)NULL)->system_time)); } /* @@ -135,15 +131,7 @@ static inline void kvm_sched_clock_init(bool stable) */ static unsigned long kvm_get_tsc_khz(void) { - struct pvclock_vcpu_time_info *src; - int cpu; - unsigned long tsc_khz; - - cpu = get_cpu(); - src = _clock[cpu].pvti; - tsc_khz = pvclock_tsc_khz(src); - put_cpu(); - return tsc_khz; + return pvclock_tsc_khz(_clock[0].pvti); } static void kvm_get_preset_lpj(void) @@ -160,29 +148,27 @@ static void kvm_get_preset_lpj(void) bool kvm_check_and_clear_guest_paused(void) { - bool ret = false; struct pvclock_vcpu_time_info *src; - int cpu = smp_processor_id(); + bool ret = false; if (!hv_clock) return ret; - src = _clock[cpu].pvti; + src = _clock[smp_processor_id()].pvti; if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) { src->flags &= ~PVCLOCK_GUEST_STOPPED; pvclock_touch_watchdogs(); ret = true; } - return ret; } struct clocksource kvm_clock = { - .name = "kvm-clock", - .read = kvm_clock_get_cycles, - .rating = 400, - .mask = CLOCKSOURCE_MASK(64), - .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .name = "kvm-clock", + .read = kvm_clock_get_cycles, + .rating = 400, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; EXPORT_SYMBOL_GPL(kvm_clock); @@ -198,7 +184,7 @@ static void kvm_register_clock(char *txt) src = _clock[cpu].pvti; pa = slow_virt_to_phys(src) | 0x01ULL; wrmsrl(msr_kvm_system_time, pa); - pr_info("kvm-clock: cpu %d, msr %llx, %s\n", cpu, pa, txt); + pr_info("kvm-clock: cpu %d, msr %llx, %s", cpu, pa, txt); } static void kvm_save_sched_clock_state(void) @@ -243,20 +229,19 @@ static void kvm_shutdown(void) void __init kvmclock_init(void) { - struct pvclock_vcpu_time_info *vcpu_time; - int cpu; u8 flags; - if (!kvm_para_available()) + if (!kvm_para_available() || !kvmclock) return; - if (kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { + if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE2)) { msr_kvm_system_time = MSR_KVM_SYSTEM_TIME_NEW; msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK_NEW; - } else if (!(kvmclock && kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE))) + } else if (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) { return; + }