LoongArch: KVM: Add PV steal time support in guest side
commit 03779999ac30 ("LoongArch: KVM: Add PV steal time support in guest side")
Conflict: none
Backport-reason: Synchronize upstream linux loongarch kvm
patch to support loongarch virtualization.
Checkpatch: no, to be consistent with upstream commit.
Per-cpu struct kvm_steal_time is added here, its size is 64 bytes and
also defined as 64 bytes, so that the whole structure is in one physical
page.
When a VCPU is online, function pv_enable_steal_time() is called. This
function will pass guest physical address of struct kvm_steal_time and
tells hypervisor to enable steal time. When a vcpu is offline, physical
address is set as 0 and tells hypervisor to disable steal time.
Here is an output of vmstat on guest when there is workload on both host
and guest. It shows steal time stat information.
procs -----------memory---------- -----io---- -system-- ------cpu-----
r b swpd free inact active bi bo in cs us sy id wa st
15 1 0 7583616 184112 72208 20 0 162 52 31 6 43 0 20
17 0 0 7583616 184704 72192 0 0 6318 6885 5 60 8 5 22
16 0 0 7583616 185392 72144 0 0 1766 1081 0 49 0 1 50
16 0 0 7583616 184816 72304 0 0 6300 6166 4 62 12 2 20
18 0 0 7583632 184480 72240 0 0 2814 1754 2 58 4 1 35
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Xianglai Li <lixianglai@loongson.cn>
This commit is contained in:
Bibo Mao
Xianglai Li
parent
b6fbeefb06
commit
c555314c68
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@ -3948,9 +3948,10 @@
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vulnerability. System may allow data leaks with this
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option.
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no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES] Disable paravirtualized
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steal time accounting. steal time is computed, but
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won't influence scheduler behaviour
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no-steal-acc [X86,PV_OPS,ARM64,PPC/PSERIES,RISCV,LOONGARCH,EARLY]
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Disable paravirtualized steal time accounting. steal time
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is computed, but won't influence scheduler behaviour
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nosync [HW,M68K] Disables sync negotiation for all devices.
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@ -628,6 +628,17 @@ config PARAVIRT
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over full virtualization. However, when run without a hypervisor
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the kernel is theoretically slower and slightly larger.
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config PARAVIRT_TIME_ACCOUNTING
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bool "Paravirtual steal time accounting"
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depends on PARAVIRT
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help
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Select this option to enable fine granularity task steal time
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accounting. Time spent executing other tasks in parallel with
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the current vCPU is discounted from the vCPU power. To account for
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that, there can be a small performance impact.
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If in doubt, say N here.
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endmenu
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config ARCH_SELECT_MEMORY_MODEL
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@ -680,6 +691,17 @@ source "drivers/cpufreq/Kconfig"
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source "kernel/power/Kconfig"
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source "drivers/acpi/Kconfig"
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config PARAVIRT_TIME_ACCOUNTING
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bool "Paravirtual steal time accounting"
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depends on PARAVIRT
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help
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Select this option to enable fine granularity task steal time
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accounting. Time spent executing other tasks in parallel with
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the current vCPU is discounted from the vCPU power. To account for
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that, there can be a small performance impact.
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If in doubt, say N here.
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endmenu
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source "arch/loongarch/kvm/Kconfig"
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@ -8,10 +8,10 @@
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#include <linux/reboot.h>
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#include <linux/static_call.h>
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static int has_steal_clock;
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struct static_key paravirt_steal_enabled;
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struct static_key paravirt_steal_rq_enabled;
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static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
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static int has_steal_clock;
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static u64 native_steal_clock(int cpu)
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{
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@ -71,6 +71,62 @@ static int pv_register_steal_time(void)
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return 0;
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}
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static bool steal_acc = true;
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static int __init parse_no_stealacc(char *arg)
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{
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steal_acc = false;
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return 0;
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}
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early_param("no-steal-acc", parse_no_stealacc);
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static u64 paravt_steal_clock(int cpu)
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{
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int version;
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u64 steal;
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struct kvm_steal_time *src;
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src = &per_cpu(steal_time, cpu);
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do {
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version = src->version;
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virt_rmb(); /* Make sure that the version is read before the steal */
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steal = src->steal;
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virt_rmb(); /* Make sure that the steal is read before the next version */
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} while ((version & 1) || (version != src->version));
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return steal;
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}
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static bool steal_acc = true;
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static int __init parse_no_stealacc(char *arg)
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{
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steal_acc = false;
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return 0;
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}
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early_param("no-steal-acc", parse_no_stealacc);
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static u64 paravt_steal_clock(int cpu)
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{
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int version;
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u64 steal;
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struct kvm_steal_time *src;
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src = &per_cpu(steal_time, cpu);
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do {
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version = src->version;
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virt_rmb(); /* Make sure that the version is read before the steal */
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steal = src->steal;
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virt_rmb(); /* Make sure that the steal is read before the next version */
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} while ((version & 1) || (version != src->version));
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return steal;
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}
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#ifdef CONFIG_SMP
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static void pv_send_ipi_single(int cpu, unsigned int action)
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{
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@ -279,3 +335,231 @@ int __init pv_time_init(void)
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pr_info("Using stolen time PV\n");
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return 0;
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}
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static int pv_enable_steal_time(void)
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{
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int cpu = smp_processor_id();
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unsigned long addr;
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struct kvm_steal_time *st;
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if (!has_steal_clock)
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return -EPERM;
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st = &per_cpu(steal_time, cpu);
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addr = per_cpu_ptr_to_phys(st);
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/* The whole structure kvm_steal_time should be in one page */
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if (PFN_DOWN(addr) != PFN_DOWN(addr + sizeof(*st))) {
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pr_warn("Illegal PV steal time addr %lx\n", addr);
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return -EFAULT;
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}
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addr |= KVM_STEAL_PHYS_VALID;
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kvm_hypercall2(KVM_HCALL_FUNC_NOTIFY, KVM_FEATURE_STEAL_TIME, addr);
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return 0;
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}
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static void pv_disable_steal_time(void)
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{
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if (has_steal_clock)
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kvm_hypercall2(KVM_HCALL_FUNC_NOTIFY, KVM_FEATURE_STEAL_TIME, 0);
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}
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#ifdef CONFIG_SMP
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static int pv_time_cpu_online(unsigned int cpu)
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{
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unsigned long flags;
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local_irq_save(flags);
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pv_enable_steal_time();
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local_irq_restore(flags);
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return 0;
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}
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static int pv_time_cpu_down_prepare(unsigned int cpu)
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{
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unsigned long flags;
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local_irq_save(flags);
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pv_disable_steal_time();
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local_irq_restore(flags);
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return 0;
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}
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#endif
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static void pv_cpu_reboot(void *unused)
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{
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pv_disable_steal_time();
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}
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static int pv_reboot_notify(struct notifier_block *nb, unsigned long code, void *unused)
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{
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on_each_cpu(pv_cpu_reboot, NULL, 1);
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return NOTIFY_DONE;
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}
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static struct notifier_block pv_reboot_nb = {
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.notifier_call = pv_reboot_notify,
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};
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int __init pv_time_init(void)
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{
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int r, feature;
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if (!cpu_has_hypervisor)
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return 0;
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if (!kvm_para_available())
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return 0;
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feature = read_cpucfg(CPUCFG_KVM_FEATURE);
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if (!(feature & KVM_FEATURE_STEAL_TIME))
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return 0;
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has_steal_clock = 1;
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r = pv_enable_steal_time();
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if (r < 0) {
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has_steal_clock = 0;
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return 0;
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}
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register_reboot_notifier(&pv_reboot_nb);
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#ifdef CONFIG_SMP
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r = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
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"loongarch/pv_time:online",
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pv_time_cpu_online, pv_time_cpu_down_prepare);
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if (r < 0) {
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has_steal_clock = 0;
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pr_err("Failed to install cpu hotplug callbacks\n");
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return r;
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}
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#endif
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static_call_update(pv_steal_clock, paravt_steal_clock);
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static_key_slow_inc(¶virt_steal_enabled);
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#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
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if (steal_acc)
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static_key_slow_inc(¶virt_steal_rq_enabled);
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#endif
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pr_info("Using paravirt steal-time\n");
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return 0;
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}
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static int pv_enable_steal_time(void)
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{
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int cpu = smp_processor_id();
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unsigned long addr;
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struct kvm_steal_time *st;
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if (!has_steal_clock)
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return -EPERM;
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st = &per_cpu(steal_time, cpu);
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addr = per_cpu_ptr_to_phys(st);
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/* The whole structure kvm_steal_time should be in one page */
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if (PFN_DOWN(addr) != PFN_DOWN(addr + sizeof(*st))) {
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pr_warn("Illegal PV steal time addr %lx\n", addr);
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return -EFAULT;
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}
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addr |= KVM_STEAL_PHYS_VALID;
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kvm_hypercall2(KVM_HCALL_FUNC_NOTIFY, KVM_FEATURE_STEAL_TIME, addr);
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return 0;
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}
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static void pv_disable_steal_time(void)
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{
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if (has_steal_clock)
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kvm_hypercall2(KVM_HCALL_FUNC_NOTIFY, KVM_FEATURE_STEAL_TIME, 0);
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}
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#ifdef CONFIG_SMP
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static int pv_time_cpu_online(unsigned int cpu)
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{
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unsigned long flags;
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local_irq_save(flags);
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pv_enable_steal_time();
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local_irq_restore(flags);
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return 0;
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}
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static int pv_time_cpu_down_prepare(unsigned int cpu)
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{
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unsigned long flags;
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local_irq_save(flags);
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pv_disable_steal_time();
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local_irq_restore(flags);
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return 0;
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}
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#endif
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static void pv_cpu_reboot(void *unused)
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{
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pv_disable_steal_time();
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}
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static int pv_reboot_notify(struct notifier_block *nb, unsigned long code, void *unused)
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{
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on_each_cpu(pv_cpu_reboot, NULL, 1);
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return NOTIFY_DONE;
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}
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static struct notifier_block pv_reboot_nb = {
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.notifier_call = pv_reboot_notify,
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};
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int __init pv_time_init(void)
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{
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int r, feature;
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if (!cpu_has_hypervisor)
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return 0;
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if (!kvm_para_available())
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return 0;
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feature = read_cpucfg(CPUCFG_KVM_FEATURE);
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if (!(feature & KVM_FEATURE_STEAL_TIME))
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return 0;
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has_steal_clock = 1;
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r = pv_enable_steal_time();
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if (r < 0) {
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has_steal_clock = 0;
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return 0;
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}
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register_reboot_notifier(&pv_reboot_nb);
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#ifdef CONFIG_SMP
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r = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
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"loongarch/pv_time:online",
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pv_time_cpu_online, pv_time_cpu_down_prepare);
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if (r < 0) {
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has_steal_clock = 0;
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pr_err("Failed to install cpu hotplug callbacks\n");
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return r;
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}
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#endif
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static_call_update(pv_steal_clock, paravt_steal_clock);
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static_key_slow_inc(¶virt_steal_enabled);
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#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
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if (steal_acc)
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static_key_slow_inc(¶virt_steal_rq_enabled);
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#endif
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pr_info("Using paravirt steal-time\n");
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return 0;
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}
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