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Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c107
1 files changed, 63 insertions, 44 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 9102ae172d2a..4fd482fb9260 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -72,11 +72,11 @@ module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
/* Default doubles per-vcpu halt_poll_ns. */
static unsigned int halt_poll_ns_grow = 2;
-module_param(halt_poll_ns_grow, int, S_IRUGO);
+module_param(halt_poll_ns_grow, uint, S_IRUGO | S_IWUSR);
/* Default resets per-vcpu halt_poll_ns . */
static unsigned int halt_poll_ns_shrink;
-module_param(halt_poll_ns_shrink, int, S_IRUGO);
+module_param(halt_poll_ns_shrink, uint, S_IRUGO | S_IWUSR);
/*
* Ordering of locks:
@@ -170,8 +170,8 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
kvm_make_request(req, vcpu);
cpu = vcpu->cpu;
- /* Set ->requests bit before we read ->mode */
- smp_mb();
+ /* Set ->requests bit before we read ->mode. */
+ smp_mb__after_atomic();
if (cpus != NULL && cpu != -1 && cpu != me &&
kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE)
@@ -191,9 +191,23 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
#ifndef CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL
void kvm_flush_remote_tlbs(struct kvm *kvm)
{
- long dirty_count = kvm->tlbs_dirty;
+ /*
+ * Read tlbs_dirty before setting KVM_REQ_TLB_FLUSH in
+ * kvm_make_all_cpus_request.
+ */
+ long dirty_count = smp_load_acquire(&kvm->tlbs_dirty);
- smp_mb();
+ /*
+ * We want to publish modifications to the page tables before reading
+ * mode. Pairs with a memory barrier in arch-specific code.
+ * - x86: smp_mb__after_srcu_read_unlock in vcpu_enter_guest
+ * and smp_mb in walk_shadow_page_lockless_begin/end.
+ * - powerpc: smp_mb in kvmppc_prepare_to_enter.
+ *
+ * There is already an smp_mb__after_atomic() before
+ * kvm_make_all_cpus_request() reads vcpu->mode. We reuse that
+ * barrier here.
+ */
if (kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH))
++kvm->stat.remote_tlb_flush;
cmpxchg(&kvm->tlbs_dirty, dirty_count, 0);
@@ -216,8 +230,7 @@ int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
vcpu->kvm = kvm;
vcpu->vcpu_id = id;
vcpu->pid = NULL;
- vcpu->halt_poll_ns = 0;
- init_waitqueue_head(&vcpu->wq);
+ init_swait_queue_head(&vcpu->wq);
kvm_async_pf_vcpu_init(vcpu);
vcpu->pre_pcpu = -1;
@@ -537,6 +550,16 @@ static struct kvm *kvm_create_vm(unsigned long type)
if (!kvm)
return ERR_PTR(-ENOMEM);
+ spin_lock_init(&kvm->mmu_lock);
+ atomic_inc(&current->mm->mm_count);
+ kvm->mm = current->mm;
+ kvm_eventfd_init(kvm);
+ mutex_init(&kvm->lock);
+ mutex_init(&kvm->irq_lock);
+ mutex_init(&kvm->slots_lock);
+ atomic_set(&kvm->users_count, 1);
+ INIT_LIST_HEAD(&kvm->devices);
+
r = kvm_arch_init_vm(kvm, type);
if (r)
goto out_err_no_disable;
@@ -569,16 +592,6 @@ static struct kvm *kvm_create_vm(unsigned long type)
goto out_err;
}
- spin_lock_init(&kvm->mmu_lock);
- kvm->mm = current->mm;
- atomic_inc(&kvm->mm->mm_count);
- kvm_eventfd_init(kvm);
- mutex_init(&kvm->lock);
- mutex_init(&kvm->irq_lock);
- mutex_init(&kvm->slots_lock);
- atomic_set(&kvm->users_count, 1);
- INIT_LIST_HEAD(&kvm->devices);
-
r = kvm_init_mmu_notifier(kvm);
if (r)
goto out_err;
@@ -603,6 +616,7 @@ out_err_no_disable:
for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++)
kvm_free_memslots(kvm, kvm->memslots[i]);
kvm_arch_free_vm(kvm);
+ mmdrop(current->mm);
return ERR_PTR(r);
}
@@ -620,13 +634,10 @@ void *kvm_kvzalloc(unsigned long size)
static void kvm_destroy_devices(struct kvm *kvm)
{
- struct list_head *node, *tmp;
-
- list_for_each_safe(node, tmp, &kvm->devices) {
- struct kvm_device *dev =
- list_entry(node, struct kvm_device, vm_node);
+ struct kvm_device *dev, *tmp;
- list_del(node);
+ list_for_each_entry_safe(dev, tmp, &kvm->devices, vm_node) {
+ list_del(&dev->vm_node);
dev->ops->destroy(dev);
}
}
@@ -1264,15 +1275,16 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}
-static int get_user_page_nowait(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int write, struct page **page)
+static int get_user_page_nowait(unsigned long start, int write,
+ struct page **page)
{
int flags = FOLL_TOUCH | FOLL_NOWAIT | FOLL_HWPOISON | FOLL_GET;
if (write)
flags |= FOLL_WRITE;
- return __get_user_pages(tsk, mm, start, 1, flags, page, NULL, NULL);
+ return __get_user_pages(current, current->mm, start, 1, flags, page,
+ NULL, NULL);
}
static inline int check_user_page_hwpoison(unsigned long addr)
@@ -1334,8 +1346,7 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
if (async) {
down_read(&current->mm->mmap_sem);
- npages = get_user_page_nowait(current, current->mm,
- addr, write_fault, page);
+ npages = get_user_page_nowait(addr, write_fault, page);
up_read(&current->mm->mmap_sem);
} else
npages = __get_user_pages_unlocked(current, current->mm, addr, 1,
@@ -1437,11 +1448,17 @@ kvm_pfn_t __gfn_to_pfn_memslot(struct kvm_memory_slot *slot, gfn_t gfn,
{
unsigned long addr = __gfn_to_hva_many(slot, gfn, NULL, write_fault);
- if (addr == KVM_HVA_ERR_RO_BAD)
+ if (addr == KVM_HVA_ERR_RO_BAD) {
+ if (writable)
+ *writable = false;
return KVM_PFN_ERR_RO_FAULT;
+ }
- if (kvm_is_error_hva(addr))
+ if (kvm_is_error_hva(addr)) {
+ if (writable)
+ *writable = false;
return KVM_PFN_NOSLOT;
+ }
/* Do not map writable pfn in the readonly memslot. */
if (writable && memslot_is_readonly(slot)) {
@@ -1943,14 +1960,15 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_mark_page_dirty);
static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
{
- int old, val;
+ unsigned int old, val, grow;
old = val = vcpu->halt_poll_ns;
+ grow = READ_ONCE(halt_poll_ns_grow);
/* 10us base */
- if (val == 0 && halt_poll_ns_grow)
+ if (val == 0 && grow)
val = 10000;
else
- val *= halt_poll_ns_grow;
+ val *= grow;
if (val > halt_poll_ns)
val = halt_poll_ns;
@@ -1961,13 +1979,14 @@ static void grow_halt_poll_ns(struct kvm_vcpu *vcpu)
static void shrink_halt_poll_ns(struct kvm_vcpu *vcpu)
{
- int old, val;
+ unsigned int old, val, shrink;
old = val = vcpu->halt_poll_ns;
- if (halt_poll_ns_shrink == 0)
+ shrink = READ_ONCE(halt_poll_ns_shrink);
+ if (shrink == 0)
val = 0;
else
- val /= halt_poll_ns_shrink;
+ val /= shrink;
vcpu->halt_poll_ns = val;
trace_kvm_halt_poll_ns_shrink(vcpu->vcpu_id, val, old);
@@ -1993,7 +2012,7 @@ static int kvm_vcpu_check_block(struct kvm_vcpu *vcpu)
void kvm_vcpu_block(struct kvm_vcpu *vcpu)
{
ktime_t start, cur;
- DEFINE_WAIT(wait);
+ DECLARE_SWAITQUEUE(wait);
bool waited = false;
u64 block_ns;
@@ -2018,7 +2037,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
kvm_arch_vcpu_blocking(vcpu);
for (;;) {
- prepare_to_wait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
+ prepare_to_swait(&vcpu->wq, &wait, TASK_INTERRUPTIBLE);
if (kvm_vcpu_check_block(vcpu) < 0)
break;
@@ -2027,7 +2046,7 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu)
schedule();
}
- finish_wait(&vcpu->wq, &wait);
+ finish_swait(&vcpu->wq, &wait);
cur = ktime_get();
kvm_arch_vcpu_unblocking(vcpu);
@@ -2059,11 +2078,11 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
{
int me;
int cpu = vcpu->cpu;
- wait_queue_head_t *wqp;
+ struct swait_queue_head *wqp;
wqp = kvm_arch_vcpu_wq(vcpu);
- if (waitqueue_active(wqp)) {
- wake_up_interruptible(wqp);
+ if (swait_active(wqp)) {
+ swake_up(wqp);
++vcpu->stat.halt_wakeup;
}
@@ -2164,7 +2183,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
continue;
if (vcpu == me)
continue;
- if (waitqueue_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
+ if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
continue;
if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
continue;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.