1 files changed, 868 insertions, 0 deletions

diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
new file mode 100644
index 000000000..bd6ee0bfa
--- /dev/null
+++ b/arch/x86/kernel/kvm.c
@@ -0,0 +1,868 @@
+/*
+ * KVM paravirt_ops implementation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (C) 2007, Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ * Copyright IBM Corporation, 2007
+ *   Authors: Anthony Liguori <aliguori@us.ibm.com>
+ */
+
+#include <linux/context_tracking.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/kvm_para.h>
+#include <linux/cpu.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/hardirq.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/hash.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/kprobes.h>
+#include <linux/debugfs.h>
+#include <linux/nmi.h>
+#include <linux/swait.h>
+#include <asm/timer.h>
+#include <asm/cpu.h>
+#include <asm/traps.h>
+#include <asm/desc.h>
+#include <asm/tlbflush.h>
+#include <asm/apic.h>
+#include <asm/apicdef.h>
+#include <asm/hypervisor.h>
+#include <asm/tlb.h>
+
+static int kvmapf = 1;
+
+static int __init parse_no_kvmapf(char *arg)
+{
+        kvmapf = 0;
+        return 0;
+}
+
+early_param("no-kvmapf", parse_no_kvmapf);
+
+static int steal_acc = 1;
+static int __init parse_no_stealacc(char *arg)
+{
+        steal_acc = 0;
+        return 0;
+}
+
+early_param("no-steal-acc", parse_no_stealacc);
+
+static DEFINE_PER_CPU_DECRYPTED(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);
+static DEFINE_PER_CPU_DECRYPTED(struct kvm_steal_time, steal_time) __aligned(64);
+static int has_steal_clock = 0;
+
+/*
+ * No need for any "IO delay" on KVM
+ */
+static void kvm_io_delay(void)
+{
+}
+
+#define KVM_TASK_SLEEP_HASHBITS 8
+#define KVM_TASK_SLEEP_HASHSIZE (1<<KVM_TASK_SLEEP_HASHBITS)
+
+struct kvm_task_sleep_node {
+	struct hlist_node link;
+	struct swait_queue_head wq;
+	u32 token;
+	int cpu;
+	bool halted;
+};
+
+static struct kvm_task_sleep_head {
+	raw_spinlock_t lock;
+	struct hlist_head list;
+} async_pf_sleepers[KVM_TASK_SLEEP_HASHSIZE];
+
+static struct kvm_task_sleep_node *_find_apf_task(struct kvm_task_sleep_head *b,
+						  u32 token)
+{
+	struct hlist_node *p;
+
+	hlist_for_each(p, &b->list) {
+		struct kvm_task_sleep_node *n =
+			hlist_entry(p, typeof(*n), link);
+		if (n->token == token)
+			return n;
+	}
+
+	return NULL;
+}
+
+/*
+ * @interrupt_kernel: Is this called from a routine which interrupts the kernel
+ * 		      (other than user space)?
+ */
+void kvm_async_pf_task_wait(u32 token, int interrupt_kernel)
+{
+	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
+	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
+	struct kvm_task_sleep_node n, *e;
+	DECLARE_SWAITQUEUE(wait);
+
+	rcu_irq_enter();
+
+	raw_spin_lock(&b->lock);
+	e = _find_apf_task(b, token);
+	if (e) {
+		/* dummy entry exist -> wake up was delivered ahead of PF */
+		hlist_del(&e->link);
+		kfree(e);
+		raw_spin_unlock(&b->lock);
+
+		rcu_irq_exit();
+		return;
+	}
+
+	n.token = token;
+	n.cpu = smp_processor_id();
+	n.halted = is_idle_task(current) ||
+		   (IS_ENABLED(CONFIG_PREEMPT_COUNT)
+		    ? preempt_count() > 1 || rcu_preempt_depth()
+		    : interrupt_kernel);
+	init_swait_queue_head(&n.wq);
+	hlist_add_head(&n.link, &b->list);
+	raw_spin_unlock(&b->lock);
+
+	for (;;) {
+		if (!n.halted)
+			prepare_to_swait_exclusive(&n.wq, &wait, TASK_UNINTERRUPTIBLE);
+		if (hlist_unhashed(&n.link))
+			break;
+
+		rcu_irq_exit();
+
+		if (!n.halted) {
+			local_irq_enable();
+			schedule();
+			local_irq_disable();
+		} else {
+			/*
+			 * We cannot reschedule. So halt.
+			 */
+			native_safe_halt();
+			local_irq_disable();
+		}
+
+		rcu_irq_enter();
+	}
+	if (!n.halted)
+		finish_swait(&n.wq, &wait);
+
+	rcu_irq_exit();
+	return;
+}
+EXPORT_SYMBOL_GPL(kvm_async_pf_task_wait);
+
+static void apf_task_wake_one(struct kvm_task_sleep_node *n)
+{
+	hlist_del_init(&n->link);
+	if (n->halted)
+		smp_send_reschedule(n->cpu);
+	else if (swq_has_sleeper(&n->wq))
+		swake_up_one(&n->wq);
+}
+
+static void apf_task_wake_all(void)
+{
+	int i;
+
+	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++) {
+		struct hlist_node *p, *next;
+		struct kvm_task_sleep_head *b = &async_pf_sleepers[i];
+		raw_spin_lock(&b->lock);
+		hlist_for_each_safe(p, next, &b->list) {
+			struct kvm_task_sleep_node *n =
+				hlist_entry(p, typeof(*n), link);
+			if (n->cpu == smp_processor_id())
+				apf_task_wake_one(n);
+		}
+		raw_spin_unlock(&b->lock);
+	}
+}
+
+void kvm_async_pf_task_wake(u32 token)
+{
+	u32 key = hash_32(token, KVM_TASK_SLEEP_HASHBITS);
+	struct kvm_task_sleep_head *b = &async_pf_sleepers[key];
+	struct kvm_task_sleep_node *n;
+
+	if (token == ~0) {
+		apf_task_wake_all();
+		return;
+	}
+
+again:
+	raw_spin_lock(&b->lock);
+	n = _find_apf_task(b, token);
+	if (!n) {
+		/*
+		 * async PF was not yet handled.
+		 * Add dummy entry for the token.
+		 */
+		n = kzalloc(sizeof(*n), GFP_ATOMIC);
+		if (!n) {
+			/*
+			 * Allocation failed! Busy wait while other cpu
+			 * handles async PF.
+			 */
+			raw_spin_unlock(&b->lock);
+			cpu_relax();
+			goto again;
+		}
+		n->token = token;
+		n->cpu = smp_processor_id();
+		init_swait_queue_head(&n->wq);
+		hlist_add_head(&n->link, &b->list);
+	} else
+		apf_task_wake_one(n);
+	raw_spin_unlock(&b->lock);
+	return;
+}
+EXPORT_SYMBOL_GPL(kvm_async_pf_task_wake);
+
+u32 kvm_read_and_reset_pf_reason(void)
+{
+	u32 reason = 0;
+
+	if (__this_cpu_read(apf_reason.enabled)) {
+		reason = __this_cpu_read(apf_reason.reason);
+		__this_cpu_write(apf_reason.reason, 0);
+	}
+
+	return reason;
+}
+EXPORT_SYMBOL_GPL(kvm_read_and_reset_pf_reason);
+NOKPROBE_SYMBOL(kvm_read_and_reset_pf_reason);
+
+dotraplinkage void
+do_async_page_fault(struct pt_regs *regs, unsigned long error_code)
+{
+	enum ctx_state prev_state;
+
+	switch (kvm_read_and_reset_pf_reason()) {
+	default:
+		do_page_fault(regs, error_code);
+		break;
+	case KVM_PV_REASON_PAGE_NOT_PRESENT:
+		/* page is swapped out by the host. */
+		prev_state = exception_enter();
+		kvm_async_pf_task_wait((u32)read_cr2(), !user_mode(regs));
+		exception_exit(prev_state);
+		break;
+	case KVM_PV_REASON_PAGE_READY:
+		rcu_irq_enter();
+		kvm_async_pf_task_wake((u32)read_cr2());
+		rcu_irq_exit();
+		break;
+	}
+}
+NOKPROBE_SYMBOL(do_async_page_fault);
+
+static void __init paravirt_ops_setup(void)
+{
+	pv_info.name = "KVM";
+
+	if (kvm_para_has_feature(KVM_FEATURE_NOP_IO_DELAY))
+		pv_cpu_ops.io_delay = kvm_io_delay;
+
+#ifdef CONFIG_X86_IO_APIC
+	no_timer_check = 1;
+#endif
+}
+
+static void kvm_register_steal_time(void)
+{
+	int cpu = smp_processor_id();
+	struct kvm_steal_time *st = &per_cpu(steal_time, cpu);
+
+	if (!has_steal_clock)
+		return;
+
+	wrmsrl(MSR_KVM_STEAL_TIME, (slow_virt_to_phys(st) | KVM_MSR_ENABLED));
+	pr_info("kvm-stealtime: cpu %d, msr %llx\n",
+		cpu, (unsigned long long) slow_virt_to_phys(st));
+}
+
+static DEFINE_PER_CPU_DECRYPTED(unsigned long, kvm_apic_eoi) = KVM_PV_EOI_DISABLED;
+
+static notrace void kvm_guest_apic_eoi_write(u32 reg, u32 val)
+{
+	/**
+	 * This relies on __test_and_clear_bit to modify the memory
+	 * in a way that is atomic with respect to the local CPU.
+	 * The hypervisor only accesses this memory from the local CPU so
+	 * there's no need for lock or memory barriers.
+	 * An optimization barrier is implied in apic write.
+	 */
+	if (__test_and_clear_bit(KVM_PV_EOI_BIT, this_cpu_ptr(&kvm_apic_eoi)))
+		return;
+	apic->native_eoi_write(APIC_EOI, APIC_EOI_ACK);
+}
+
+static void kvm_guest_cpu_init(void)
+{
+	if (!kvm_para_available())
+		return;
+
+	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF) && kvmapf) {
+		u64 pa = slow_virt_to_phys(this_cpu_ptr(&apf_reason));
+
+#ifdef CONFIG_PREEMPT
+		pa |= KVM_ASYNC_PF_SEND_ALWAYS;
+#endif
+		pa |= KVM_ASYNC_PF_ENABLED;
+
+		if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF_VMEXIT))
+			pa |= KVM_ASYNC_PF_DELIVERY_AS_PF_VMEXIT;
+
+		wrmsrl(MSR_KVM_ASYNC_PF_EN, pa);
+		__this_cpu_write(apf_reason.enabled, 1);
+		printk(KERN_INFO"KVM setup async PF for cpu %d\n",
+		       smp_processor_id());
+	}
+
+	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI)) {
+		unsigned long pa;
+		/* Size alignment is implied but just to make it explicit. */
+		BUILD_BUG_ON(__alignof__(kvm_apic_eoi) < 4);
+		__this_cpu_write(kvm_apic_eoi, 0);
+		pa = slow_virt_to_phys(this_cpu_ptr(&kvm_apic_eoi))
+			| KVM_MSR_ENABLED;
+		wrmsrl(MSR_KVM_PV_EOI_EN, pa);
+	}
+
+	if (has_steal_clock)
+		kvm_register_steal_time();
+}
+
+static void kvm_pv_disable_apf(void)
+{
+	if (!__this_cpu_read(apf_reason.enabled))
+		return;
+
+	wrmsrl(MSR_KVM_ASYNC_PF_EN, 0);
+	__this_cpu_write(apf_reason.enabled, 0);
+
+	printk(KERN_INFO"Unregister pv shared memory for cpu %d\n",
+	       smp_processor_id());
+}
+
+static void kvm_pv_guest_cpu_reboot(void *unused)
+{
+	/*
+	 * We disable PV EOI before we load a new kernel by kexec,
+	 * since MSR_KVM_PV_EOI_EN stores a pointer into old kernel's memory.
+	 * New kernel can re-enable when it boots.
+	 */
+	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+		wrmsrl(MSR_KVM_PV_EOI_EN, 0);
+	kvm_pv_disable_apf();
+	kvm_disable_steal_time();
+}
+
+static int kvm_pv_reboot_notify(struct notifier_block *nb,
+				unsigned long code, void *unused)
+{
+	if (code == SYS_RESTART)
+		on_each_cpu(kvm_pv_guest_cpu_reboot, NULL, 1);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block kvm_pv_reboot_nb = {
+	.notifier_call = kvm_pv_reboot_notify,
+};
+
+static u64 kvm_steal_clock(int cpu)
+{
+	u64 steal;
+	struct kvm_steal_time *src;
+	int version;
+
+	src = &per_cpu(steal_time, cpu);
+	do {
+		version = src->version;
+		virt_rmb();
+		steal = src->steal;
+		virt_rmb();
+	} while ((version & 1) || (version != src->version));
+
+	return steal;
+}
+
+void kvm_disable_steal_time(void)
+{
+	if (!has_steal_clock)
+		return;
+
+	wrmsr(MSR_KVM_STEAL_TIME, 0, 0);
+}
+
+static inline void __set_percpu_decrypted(void *ptr, unsigned long size)
+{
+	early_set_memory_decrypted((unsigned long) ptr, size);
+}
+
+/*
+ * Iterate through all possible CPUs and map the memory region pointed
+ * by apf_reason, steal_time and kvm_apic_eoi as decrypted at once.
+ *
+ * Note: we iterate through all possible CPUs to ensure that CPUs
+ * hotplugged will have their per-cpu variable already mapped as
+ * decrypted.
+ */
+static void __init sev_map_percpu_data(void)
+{
+	int cpu;
+
+	if (!sev_active())
+		return;
+
+	for_each_possible_cpu(cpu) {
+		__set_percpu_decrypted(&per_cpu(apf_reason, cpu), sizeof(apf_reason));
+		__set_percpu_decrypted(&per_cpu(steal_time, cpu), sizeof(steal_time));
+		__set_percpu_decrypted(&per_cpu(kvm_apic_eoi, cpu), sizeof(kvm_apic_eoi));
+	}
+}
+
+#ifdef CONFIG_SMP
+#define KVM_IPI_CLUSTER_SIZE	(2 * BITS_PER_LONG)
+
+static void __send_ipi_mask(const struct cpumask *mask, int vector)
+{
+	unsigned long flags;
+	int cpu, apic_id, icr;
+	int min = 0, max = 0;
+#ifdef CONFIG_X86_64
+	__uint128_t ipi_bitmap = 0;
+#else
+	u64 ipi_bitmap = 0;
+#endif
+	long ret;
+
+	if (cpumask_empty(mask))
+		return;
+
+	local_irq_save(flags);
+
+	switch (vector) {
+	default:
+		icr = APIC_DM_FIXED | vector;
+		break;
+	case NMI_VECTOR:
+		icr = APIC_DM_NMI;
+		break;
+	}
+
+	for_each_cpu(cpu, mask) {
+		apic_id = per_cpu(x86_cpu_to_apicid, cpu);
+		if (!ipi_bitmap) {
+			min = max = apic_id;
+		} else if (apic_id < min && max - apic_id < KVM_IPI_CLUSTER_SIZE) {
+			ipi_bitmap <<= min - apic_id;
+			min = apic_id;
+		} else if (apic_id > min && apic_id < min + KVM_IPI_CLUSTER_SIZE) {
+			max = apic_id < max ? max : apic_id;
+		} else {
+			ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+				(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+			WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
+			min = max = apic_id;
+			ipi_bitmap = 0;
+		}
+		__set_bit(apic_id - min, (unsigned long *)&ipi_bitmap);
+	}
+
+	if (ipi_bitmap) {
+		ret = kvm_hypercall4(KVM_HC_SEND_IPI, (unsigned long)ipi_bitmap,
+			(unsigned long)(ipi_bitmap >> BITS_PER_LONG), min, icr);
+		WARN_ONCE(ret < 0, "KVM: failed to send PV IPI: %ld", ret);
+	}
+
+	local_irq_restore(flags);
+}
+
+static void kvm_send_ipi_mask(const struct cpumask *mask, int vector)
+{
+	__send_ipi_mask(mask, vector);
+}
+
+static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
+{
+	unsigned int this_cpu = smp_processor_id();
+	struct cpumask new_mask;
+	const struct cpumask *local_mask;
+
+	cpumask_copy(&new_mask, mask);
+	cpumask_clear_cpu(this_cpu, &new_mask);
+	local_mask = &new_mask;
+	__send_ipi_mask(local_mask, vector);
+}
+
+static void kvm_send_ipi_allbutself(int vector)
+{
+	kvm_send_ipi_mask_allbutself(cpu_online_mask, vector);
+}
+
+static void kvm_send_ipi_all(int vector)
+{
+	__send_ipi_mask(cpu_online_mask, vector);
+}
+
+/*
+ * Set the IPI entry points
+ */
+static void kvm_setup_pv_ipi(void)
+{
+	apic->send_IPI_mask = kvm_send_ipi_mask;
+	apic->send_IPI_mask_allbutself = kvm_send_ipi_mask_allbutself;
+	apic->send_IPI_allbutself = kvm_send_ipi_allbutself;
+	apic->send_IPI_all = kvm_send_ipi_all;
+	pr_info("KVM setup pv IPIs\n");
+}
+
+static void __init kvm_smp_prepare_cpus(unsigned int max_cpus)
+{
+	native_smp_prepare_cpus(max_cpus);
+	if (kvm_para_has_hint(KVM_HINTS_REALTIME))
+		static_branch_disable(&virt_spin_lock_key);
+}
+
+static void __init kvm_smp_prepare_boot_cpu(void)
+{
+	/*
+	 * Map the per-cpu variables as decrypted before kvm_guest_cpu_init()
+	 * shares the guest physical address with the hypervisor.
+	 */
+	sev_map_percpu_data();
+
+	kvm_guest_cpu_init();
+	native_smp_prepare_boot_cpu();
+	kvm_spinlock_init();
+}
+
+static void kvm_guest_cpu_offline(void)
+{
+	kvm_disable_steal_time();
+	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+		wrmsrl(MSR_KVM_PV_EOI_EN, 0);
+	kvm_pv_disable_apf();
+	apf_task_wake_all();
+}
+
+static int kvm_cpu_online(unsigned int cpu)
+{
+	local_irq_disable();
+	kvm_guest_cpu_init();
+	local_irq_enable();
+	return 0;
+}
+
+static int kvm_cpu_down_prepare(unsigned int cpu)
+{
+	local_irq_disable();
+	kvm_guest_cpu_offline();
+	local_irq_enable();
+	return 0;
+}
+#endif
+
+static void __init kvm_apf_trap_init(void)
+{
+	update_intr_gate(X86_TRAP_PF, async_page_fault);
+}
+
+static DEFINE_PER_CPU(cpumask_var_t, __pv_tlb_mask);
+
+static void kvm_flush_tlb_others(const struct cpumask *cpumask,
+			const struct flush_tlb_info *info)
+{
+	u8 state;
+	int cpu;
+	struct kvm_steal_time *src;
+	struct cpumask *flushmask = this_cpu_cpumask_var_ptr(__pv_tlb_mask);
+
+	cpumask_copy(flushmask, cpumask);
+	/*
+	 * We have to call flush only on online vCPUs. And
+	 * queue flush_on_enter for pre-empted vCPUs
+	 */
+	for_each_cpu(cpu, flushmask) {
+		src = &per_cpu(steal_time, cpu);
+		state = READ_ONCE(src->preempted);
+		if ((state & KVM_VCPU_PREEMPTED)) {
+			if (try_cmpxchg(&src->preempted, &state,
+					state | KVM_VCPU_FLUSH_TLB))
+				__cpumask_clear_cpu(cpu, flushmask);
+		}
+	}
+
+	native_flush_tlb_others(flushmask, info);
+}
+
+static void __init kvm_guest_init(void)
+{
+	int i;
+
+	if (!kvm_para_available())
+		return;
+
+	paravirt_ops_setup();
+	register_reboot_notifier(&kvm_pv_reboot_nb);
+	for (i = 0; i < KVM_TASK_SLEEP_HASHSIZE; i++)
+		raw_spin_lock_init(&async_pf_sleepers[i].lock);
+	if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF))
+		x86_init.irqs.trap_init = kvm_apf_trap_init;
+
+	if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+		has_steal_clock = 1;
+		pv_time_ops.steal_clock = kvm_steal_clock;
+	}
+
+	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+	    !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+	    kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+		pv_mmu_ops.flush_tlb_others = kvm_flush_tlb_others;
+		pv_mmu_ops.tlb_remove_table = tlb_remove_table;
+	}
+
+	if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
+		apic_set_eoi_write(kvm_guest_apic_eoi_write);
+
+#ifdef CONFIG_SMP
+	smp_ops.smp_prepare_cpus = kvm_smp_prepare_cpus;
+	smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
+	if (cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "x86/kvm:online",
+				      kvm_cpu_online, kvm_cpu_down_prepare) < 0)
+		pr_err("kvm_guest: Failed to install cpu hotplug callbacks\n");
+#else
+	sev_map_percpu_data();
+	kvm_guest_cpu_init();
+#endif
+
+	/*
+	 * Hard lockup detection is enabled by default. Disable it, as guests
+	 * can get false positives too easily, for example if the host is
+	 * overcommitted.
+	 */
+	hardlockup_detector_disable();
+}
+
+static noinline uint32_t __kvm_cpuid_base(void)
+{
+	if (boot_cpu_data.cpuid_level < 0)
+		return 0;	/* So we don't blow up on old processors */
+
+	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+		return hypervisor_cpuid_base("KVMKVMKVM\0\0\0", 0);
+
+	return 0;
+}
+
+static inline uint32_t kvm_cpuid_base(void)
+{
+	static int kvm_cpuid_base = -1;
+
+	if (kvm_cpuid_base == -1)
+		kvm_cpuid_base = __kvm_cpuid_base();
+
+	return kvm_cpuid_base;
+}
+
+bool kvm_para_available(void)
+{
+	return kvm_cpuid_base() != 0;
+}
+EXPORT_SYMBOL_GPL(kvm_para_available);
+
+unsigned int kvm_arch_para_features(void)
+{
+	return cpuid_eax(kvm_cpuid_base() | KVM_CPUID_FEATURES);
+}
+
+unsigned int kvm_arch_para_hints(void)
+{
+	return cpuid_edx(kvm_cpuid_base() | KVM_CPUID_FEATURES);
+}
+
+static uint32_t __init kvm_detect(void)
+{
+	return kvm_cpuid_base();
+}
+
+static void __init kvm_apic_init(void)
+{
+#if defined(CONFIG_SMP)
+	if (kvm_para_has_feature(KVM_FEATURE_PV_SEND_IPI))
+		kvm_setup_pv_ipi();
+#endif
+}
+
+static void __init kvm_init_platform(void)
+{
+	kvmclock_init();
+	x86_platform.apic_post_init = kvm_apic_init;
+}
+
+const __initconst struct hypervisor_x86 x86_hyper_kvm = {
+	.name			= "KVM",
+	.detect			= kvm_detect,
+	.type			= X86_HYPER_KVM,
+	.init.guest_late_init	= kvm_guest_init,
+	.init.x2apic_available	= kvm_para_available,
+	.init.init_platform	= kvm_init_platform,
+};
+
+static __init int activate_jump_labels(void)
+{
+	if (has_steal_clock) {
+		static_key_slow_inc(&paravirt_steal_enabled);
+		if (steal_acc)
+			static_key_slow_inc(&paravirt_steal_rq_enabled);
+	}
+
+	return 0;
+}
+arch_initcall(activate_jump_labels);
+
+static __init int kvm_setup_pv_tlb_flush(void)
+{
+	int cpu;
+
+	if (kvm_para_has_feature(KVM_FEATURE_PV_TLB_FLUSH) &&
+	    !kvm_para_has_hint(KVM_HINTS_REALTIME) &&
+	    kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+		for_each_possible_cpu(cpu) {
+			zalloc_cpumask_var_node(per_cpu_ptr(&__pv_tlb_mask, cpu),
+				GFP_KERNEL, cpu_to_node(cpu));
+		}
+		pr_info("KVM setup pv remote TLB flush\n");
+	}
+
+	return 0;
+}
+arch_initcall(kvm_setup_pv_tlb_flush);
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+
+/* Kick a cpu by its apicid. Used to wake up a halted vcpu */
+static void kvm_kick_cpu(int cpu)
+{
+	int apicid;
+	unsigned long flags = 0;
+
+	apicid = per_cpu(x86_cpu_to_apicid, cpu);
+	kvm_hypercall2(KVM_HC_KICK_CPU, flags, apicid);
+}
+
+#include <asm/qspinlock.h>
+
+static void kvm_wait(u8 *ptr, u8 val)
+{
+	unsigned long flags;
+
+	if (in_nmi())
+		return;
+
+	local_irq_save(flags);
+
+	if (READ_ONCE(*ptr) != val)
+		goto out;
+
+	/*
+	 * halt until it's our turn and kicked. Note that we do safe halt
+	 * for irq enabled case to avoid hang when lock info is overwritten
+	 * in irq spinlock slowpath and no spurious interrupt occur to save us.
+	 */
+	if (arch_irqs_disabled_flags(flags))
+		halt();
+	else
+		safe_halt();
+
+out:
+	local_irq_restore(flags);
+}
+
+#ifdef CONFIG_X86_32
+__visible bool __kvm_vcpu_is_preempted(long cpu)
+{
+	struct kvm_steal_time *src = &per_cpu(steal_time, cpu);
+
+	return !!(src->preempted & KVM_VCPU_PREEMPTED);
+}
+PV_CALLEE_SAVE_REGS_THUNK(__kvm_vcpu_is_preempted);
+
+#else
+
+#include <asm/asm-offsets.h>
+
+extern bool __raw_callee_save___kvm_vcpu_is_preempted(long);
+
+/*
+ * Hand-optimize version for x86-64 to avoid 8 64-bit register saving and
+ * restoring to/from the stack.
+ */
+asm(
+".pushsection .text;"
+".global __raw_callee_save___kvm_vcpu_is_preempted;"
+".type __raw_callee_save___kvm_vcpu_is_preempted, @function;"
+"__raw_callee_save___kvm_vcpu_is_preempted:"
+"movq	__per_cpu_offset(,%rdi,8), %rax;"
+"cmpb	$0, " __stringify(KVM_STEAL_TIME_preempted) "+steal_time(%rax);"
+"setne	%al;"
+"ret;"
+".size __raw_callee_save___kvm_vcpu_is_preempted, .-__raw_callee_save___kvm_vcpu_is_preempted;"
+".popsection");
+
+#endif
+
+/*
+ * Setup pv_lock_ops to exploit KVM_FEATURE_PV_UNHALT if present.
+ */
+void __init kvm_spinlock_init(void)
+{
+	if (!kvm_para_available())
+		return;
+	/* Does host kernel support KVM_FEATURE_PV_UNHALT? */
+	if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
+		return;
+
+	if (kvm_para_has_hint(KVM_HINTS_REALTIME))
+		return;
+
+	/* Don't use the pvqspinlock code if there is only 1 vCPU. */
+	if (num_possible_cpus() == 1)
+		return;
+
+	__pv_init_lock_hash();
+	pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
+	pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
+	pv_lock_ops.wait = kvm_wait;
+	pv_lock_ops.kick = kvm_kick_cpu;
+
+	if (kvm_para_has_feature(KVM_FEATURE_STEAL_TIME)) {
+		pv_lock_ops.vcpu_is_preempted =
+			PV_CALLEE_SAVE(__kvm_vcpu_is_preempted);
+	}
+}
+
+#endif	/* CONFIG_PARAVIRT_SPINLOCKS */