Contributors: 31
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Thomas Gleixner |
389 |
30.20% |
11 |
19.30% |
| Glauber de Oliveira Costa |
363 |
28.18% |
7 |
12.28% |
| Brijesh Singh |
181 |
14.05% |
2 |
3.51% |
| Radim Krčmář |
98 |
7.61% |
2 |
3.51% |
| Marcelo Tosatti |
86 |
6.68% |
6 |
10.53% |
| Eric B Munson |
39 |
3.03% |
1 |
1.75% |
| Gerd Hoffmann |
28 |
2.17% |
1 |
1.75% |
| Pavel Tatashin |
16 |
1.24% |
1 |
1.75% |
| Magnus Damm |
15 |
1.16% |
1 |
1.75% |
| Feng Tang |
8 |
0.62% |
1 |
1.75% |
| David Vrabel |
8 |
0.62% |
1 |
1.75% |
| Prarit Bhargava |
6 |
0.47% |
1 |
1.75% |
| Arjan Koers |
5 |
0.39% |
1 |
1.75% |
| Avi Kivity |
5 |
0.39% |
1 |
1.75% |
| Jan Kiszka |
5 |
0.39% |
1 |
1.75% |
| Luiz Fernando N. Capitulino |
4 |
0.31% |
1 |
1.75% |
| Ingo Molnar |
4 |
0.31% |
2 |
3.51% |
| Hao Peng |
3 |
0.23% |
2 |
3.51% |
| John Stultz |
3 |
0.23% |
1 |
1.75% |
| Juergen Gross |
3 |
0.23% |
1 |
1.75% |
| Linus Torvalds |
3 |
0.23% |
1 |
1.75% |
| Peter Zijlstra |
3 |
0.23% |
1 |
1.75% |
| Eduardo Pereira Habkost |
2 |
0.16% |
1 |
1.75% |
| Dave Young |
2 |
0.16% |
1 |
1.75% |
| Arnd Bergmann |
2 |
0.16% |
1 |
1.75% |
| Igor Mammedov |
2 |
0.16% |
2 |
3.51% |
| Dave Hansen |
1 |
0.08% |
1 |
1.75% |
| Jason Gunthorpe |
1 |
0.08% |
1 |
1.75% |
| Adam Buchbinder |
1 |
0.08% |
1 |
1.75% |
| Dou Liyang |
1 |
0.08% |
1 |
1.75% |
| Fernando Luis Vázquez Cao |
1 |
0.08% |
1 |
1.75% |
| Total |
1288 |
|
57 |
|
// SPDX-License-Identifier: GPL-2.0-or-later
/* KVM paravirtual clock driver. A clocksource implementation
Copyright (C) 2008 Glauber de Oliveira Costa, Red Hat Inc.
*/
#include <linux/clocksource.h>
#include <linux/kvm_para.h>
#include <asm/pvclock.h>
#include <asm/msr.h>
#include <asm/apic.h>
#include <linux/percpu.h>
#include <linux/hardirq.h>
#include <linux/cpuhotplug.h>
#include <linux/sched.h>
#include <linux/sched/clock.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/set_memory.h>
#include <asm/hypervisor.h>
#include <asm/mem_encrypt.h>
#include <asm/x86_init.h>
#include <asm/reboot.h>
#include <asm/kvmclock.h>
static int kvmclock __initdata = 1;
static int kvmclock_vsyscall __initdata = 1;
static int msr_kvm_system_time __ro_after_init = MSR_KVM_SYSTEM_TIME;
static int msr_kvm_wall_clock __ro_after_init = MSR_KVM_WALL_CLOCK;
static u64 kvm_sched_clock_offset __ro_after_init;
static int __init parse_no_kvmclock(char *arg)
{
kvmclock = 0;
return 0;
}
early_param("no-kvmclock", parse_no_kvmclock);
static int __init parse_no_kvmclock_vsyscall(char *arg)
{
kvmclock_vsyscall = 0;
return 0;
}
early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
/* Aligned to page sizes to match whats mapped via vsyscalls to userspace */
#define HV_CLOCK_SIZE (sizeof(struct pvclock_vsyscall_time_info) * NR_CPUS)
#define HVC_BOOT_ARRAY_SIZE \
(PAGE_SIZE / sizeof(struct pvclock_vsyscall_time_info))
static struct pvclock_vsyscall_time_info
hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __bss_decrypted __aligned(PAGE_SIZE);
static struct pvclock_wall_clock wall_clock __bss_decrypted;
static DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu);
static struct pvclock_vsyscall_time_info *hvclock_mem;
static inline struct pvclock_vcpu_time_info *this_cpu_pvti(void)
{
return &this_cpu_read(hv_clock_per_cpu)->pvti;
}
static inline struct pvclock_vsyscall_time_info *this_cpu_hvclock(void)
{
return this_cpu_read(hv_clock_per_cpu);
}
/*
* The wallclock is the time of day when we booted. Since then, some time may
* have elapsed since the hypervisor wrote the data. So we try to account for
* that with system time
*/
static void kvm_get_wallclock(struct timespec64 *now)
{
wrmsrl(msr_kvm_wall_clock, slow_virt_to_phys(&wall_clock));
preempt_disable();
pvclock_read_wallclock(&wall_clock, this_cpu_pvti(), now);
preempt_enable();
}
static int kvm_set_wallclock(const struct timespec64 *now)
{
return -ENODEV;
}
static u64 kvm_clock_read(void)
{
u64 ret;
preempt_disable_notrace();
ret = pvclock_clocksource_read(this_cpu_pvti());
preempt_enable_notrace();
return ret;
}
static u64 kvm_clock_get_cycles(struct clocksource *cs)
{
return kvm_clock_read();
}
static u64 kvm_sched_clock_read(void)
{
return kvm_clock_read() - kvm_sched_clock_offset;
}
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;
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));
}
/*
* If we don't do that, there is the possibility that the guest
* will calibrate under heavy load - thus, getting a lower lpj -
* and execute the delays themselves without load. This is wrong,
* because no delay loop can finish beforehand.
* Any heuristics is subject to fail, because ultimately, a large
* poll of guests can be running and trouble each other. So we preset
* lpj here
*/
static unsigned long kvm_get_tsc_khz(void)
{
setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
return pvclock_tsc_khz(this_cpu_pvti());
}
static void __init kvm_get_preset_lpj(void)
{
unsigned long khz;
u64 lpj;
khz = kvm_get_tsc_khz();
lpj = ((u64)khz * 1000);
do_div(lpj, HZ);
preset_lpj = lpj;
}
bool kvm_check_and_clear_guest_paused(void)
{
struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
bool ret = false;
if (!src)
return ret;
if ((src->pvti.flags & PVCLOCK_GUEST_STOPPED) != 0) {
src->pvti.flags &= ~PVCLOCK_GUEST_STOPPED;
pvclock_touch_watchdogs();
ret = true;
}
return ret;
}
static int kvm_cs_enable(struct clocksource *cs)
{
vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
return 0;
}
struct clocksource kvm_clock = {
.name = "kvm-clock",
.read = kvm_clock_get_cycles,
.rating = 400,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.enable = kvm_cs_enable,
};
EXPORT_SYMBOL_GPL(kvm_clock);
static void kvm_register_clock(char *txt)
{
struct pvclock_vsyscall_time_info *src = this_cpu_hvclock();
u64 pa;
if (!src)
return;
pa = slow_virt_to_phys(&src->pvti) | 0x01ULL;
wrmsrl(msr_kvm_system_time, pa);
pr_info("kvm-clock: cpu %d, msr %llx, %s", smp_processor_id(), pa, txt);
}
static void kvm_save_sched_clock_state(void)
{
}
static void kvm_restore_sched_clock_state(void)
{
kvm_register_clock("primary cpu clock, resume");
}
#ifdef CONFIG_X86_LOCAL_APIC
static void kvm_setup_secondary_clock(void)
{
kvm_register_clock("secondary cpu clock");
}
#endif
/*
* After the clock is registered, the host will keep writing to the
* registered memory location. If the guest happens to shutdown, this memory
* won't be valid. In cases like kexec, in which you install a new kernel, this
* means a random memory location will be kept being written. So before any
* kind of shutdown from our side, we unregister the clock by writing anything
* that does not have the 'enable' bit set in the msr
*/
#ifdef CONFIG_KEXEC_CORE
static void kvm_crash_shutdown(struct pt_regs *regs)
{
native_write_msr(msr_kvm_system_time, 0, 0);
kvm_disable_steal_time();
native_machine_crash_shutdown(regs);
}
#endif
static void kvm_shutdown(void)
{
native_write_msr(msr_kvm_system_time, 0, 0);
kvm_disable_steal_time();
native_machine_shutdown();
}
static void __init kvmclock_init_mem(void)
{
unsigned long ncpus;
unsigned int order;
struct page *p;
int r;
if (HVC_BOOT_ARRAY_SIZE >= num_possible_cpus())
return;
ncpus = num_possible_cpus() - HVC_BOOT_ARRAY_SIZE;
order = get_order(ncpus * sizeof(*hvclock_mem));
p = alloc_pages(GFP_KERNEL, order);
if (!p) {
pr_warn("%s: failed to alloc %d pages", __func__, (1U << order));
return;
}
hvclock_mem = page_address(p);
/*
* hvclock is shared between the guest and the hypervisor, must
* be mapped decrypted.
*/
if (sev_active()) {
r = set_memory_decrypted((unsigned long) hvclock_mem,
1UL << order);
if (r) {
__free_pages(p, order);
hvclock_mem = NULL;
pr_warn("kvmclock: set_memory_decrypted() failed. Disabling\n");
return;
}
}
memset(hvclock_mem, 0, PAGE_SIZE << order);
}
static int __init kvm_setup_vsyscall_timeinfo(void)
{
#ifdef CONFIG_X86_64
u8 flags;
if (!per_cpu(hv_clock_per_cpu, 0) || !kvmclock_vsyscall)
return 0;
flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
if (!(flags & PVCLOCK_TSC_STABLE_BIT))
return 0;
kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
#endif
kvmclock_init_mem();
return 0;
}
early_initcall(kvm_setup_vsyscall_timeinfo);
static int kvmclock_setup_percpu(unsigned int cpu)
{
struct pvclock_vsyscall_time_info *p = per_cpu(hv_clock_per_cpu, cpu);
/*
* The per cpu area setup replicates CPU0 data to all cpu
* pointers. So carefully check. CPU0 has been set up in init
* already.
*/
if (!cpu || (p && p != per_cpu(hv_clock_per_cpu, 0)))
return 0;
/* Use the static page for the first CPUs, allocate otherwise */
if (cpu < HVC_BOOT_ARRAY_SIZE)
p = &hv_clock_boot[cpu];
else if (hvclock_mem)
p = hvclock_mem + cpu - HVC_BOOT_ARRAY_SIZE;
else
return -ENOMEM;
per_cpu(hv_clock_per_cpu, cpu) = p;
return p ? 0 : -ENOMEM;
}
void __init kvmclock_init(void)
{
u8 flags;
if (!kvm_para_available() || !kvmclock)
return;
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 (!kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE)) {
return;
}
if (cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "kvmclock:setup_percpu",
kvmclock_setup_percpu, NULL) < 0) {
return;
}
pr_info("kvm-clock: Using msrs %x and %x",
msr_kvm_system_time, msr_kvm_wall_clock);
this_cpu_write(hv_clock_per_cpu, &hv_clock_boot[0]);
kvm_register_clock("primary cpu clock");
pvclock_set_pvti_cpu0_va(hv_clock_boot);
if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
flags = pvclock_read_flags(&hv_clock_boot[0].pvti);
kvm_sched_clock_init(flags & PVCLOCK_TSC_STABLE_BIT);
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;
#endif
x86_platform.save_sched_clock_state = kvm_save_sched_clock_state;
x86_platform.restore_sched_clock_state = kvm_restore_sched_clock_state;
machine_ops.shutdown = kvm_shutdown;
#ifdef CONFIG_KEXEC_CORE
machine_ops.crash_shutdown = kvm_crash_shutdown;
#endif
kvm_get_preset_lpj();
/*
* X86_FEATURE_NONSTOP_TSC is TSC runs at constant rate
* with P/T states and does not stop in deep C-states.
*
* Invariant TSC exposed by host means kvmclock is not necessary:
* can use TSC as clocksource.
*
*/
if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC) &&
boot_cpu_has(X86_FEATURE_NONSTOP_TSC) &&
!check_tsc_unstable())
kvm_clock.rating = 299;
clocksource_register_hz(&kvm_clock, NSEC_PER_SEC);
pv_info.name = "KVM";
}