From 146c394d0c3c8e88df433a179c2b0b85fd8cf247 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 19 Jul 2018 16:55:23 -0400 Subject: [PATCH] x86/kvmclock: Cleanup the code - 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 Cc: steven.sistare@oracle.com Cc: daniel.m.jordan@oracle.com Cc: linux@armlinux.org.uk Cc: schwidefsky@de.ibm.com Cc: heiko.carstens@de.ibm.com Cc: john.stultz@linaro.org Cc: sboyd@codeaurora.org Cc: hpa@zytor.com Cc: douly.fnst@cn.fujitsu.com Cc: peterz@infradead.org Cc: prarit@redhat.com Cc: feng.tang@intel.com Cc: pmladek@suse.com Cc: gnomes@lxorguk.ukuu.org.uk Cc: linux-s390@vger.kernel.org Cc: boris.ostrovsky@oracle.com Cc: jgross@suse.com Link: https://lkml.kernel.org/r/20180719205545.16512-5-pasha.tatashin@oracle.com --- arch/x86/kernel/kvmclock.c | 72 ++++++++++++-------------------------- 1 file changed, 22 insertions(+), 50 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index f0a0aef5e9fa..4afb03e49a4f 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(&wall_clock); - high = ((u64)slow_virt_to_phys(&wall_clock) >> 32); - - native_write_msr(msr_kvm_wall_clock, low, high); + wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(&wall_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)); } /* @@ -135,16 +131,8 @@ 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 = &hv_clock[cpu].pvti; - tsc_khz = pvclock_tsc_khz(src); - put_cpu(); setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); - return tsc_khz; + return pvclock_tsc_khz(&hv_clock[0].pvti); } static void kvm_get_preset_lpj(void) @@ -161,29 +149,27 @@ 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 = &hv_clock[cpu].pvti; + src = &hv_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); @@ -199,7 +185,7 @@ static void kvm_register_clock(char *txt) src = &hv_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) @@ -244,20 +230,19 @@ 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; + } - printk(KERN_INFO "kvm-clock: Using msrs %x and %x", + pr_info("kvm-clock: Using msrs %x and %x", msr_kvm_system_time, msr_kvm_wall_clock); hv_clock = (struct pvclock_vsyscall_time_info *)hv_clock_mem; @@ -267,20 +252,15 @@ void __init kvmclock_init(void) if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT)) pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); - cpu = get_cpu(); - vcpu_time = &hv_clock[cpu].pvti; - flags = pvclock_read_flags(vcpu_time); - + flags = pvclock_read_flags(&hv_clock[0].pvti); kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT); - put_cpu(); x86_platform.calibrate_tsc = kvm_get_tsc_khz; x86_platform.calibrate_cpu = kvm_get_tsc_khz; x86_platform.get_wallclock = kvm_get_wallclock; x86_platform.set_wallclock = kvm_set_wallclock; #ifdef CONFIG_X86_LOCAL_APIC - x86_cpuinit.early_percpu_clock_init = - kvm_setup_secondary_clock; + x86_cpuinit.early_percpu_clock_init = kvm_setup_secondary_clock; #endif x86_platform.save_sched_clock_state = kvm_save_sched_clock_state; x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state; @@ -296,20 +276,12 @@ void __init kvmclock_init(void) int __init kvm_setup_vsyscall_timeinfo(void) { #ifdef CONFIG_X86_64 - int cpu; u8 flags; - struct pvclock_vcpu_time_info *vcpu_time; if (!hv_clock) return 0; - cpu = get_cpu(); - - vcpu_time = &hv_clock[cpu].pvti; - flags = pvclock_read_flags(vcpu_time); - - put_cpu(); - + flags = pvclock_read_flags(&hv_clock[0].pvti); if (!(flags & PVCLOCK_TSC_STABLE_BIT)) return 1; -- GitLab