Commit 146c394d authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
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
parent 7a5ddc8f

arch/x86/kernel/kvmclock.c

+22 −50
Original line number Diff line number Diff line
@@ -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();
@@ -117,7 +113,7 @@ 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",

	pr_info("kvm-clock: using sched offset of %llu cycles",

		kvm_sched_clock_offset);



	BUILD_BUG_ON(sizeof(kvm_sched_clock_offset) >
@@ -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)
@@ -161,20 +149,18 @@ 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;

}
@@ -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;

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