*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/lockdep.h>
#include <linux/kvm_host.h>
#include <linux/rculist.h>
-#include <asm/kvm_page_track.h>
-
#include "mmu.h"
#include "mmu_internal.h"
+#include "page_track.h"
bool kvm_page_track_write_tracking_enabled(struct kvm *kvm)
{
void kvm_page_track_free_memslot(struct kvm_memory_slot *slot)
{
- int i;
-
- for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
- kvfree(slot->arch.gfn_track[i]);
- slot->arch.gfn_track[i] = NULL;
- }
+ kvfree(slot->arch.gfn_write_track);
+ slot->arch.gfn_write_track = NULL;
}
-int kvm_page_track_create_memslot(struct kvm *kvm,
- struct kvm_memory_slot *slot,
- unsigned long npages)
+static int __kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot,
+ unsigned long npages)
{
- int i;
-
- for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
- if (i == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm))
- continue;
-
- slot->arch.gfn_track[i] =
- __vcalloc(npages, sizeof(*slot->arch.gfn_track[i]),
- GFP_KERNEL_ACCOUNT);
- if (!slot->arch.gfn_track[i])
- goto track_free;
- }
+ const size_t size = sizeof(*slot->arch.gfn_write_track);
- return 0;
+ if (!slot->arch.gfn_write_track)
+ slot->arch.gfn_write_track = __vcalloc(npages, size,
+ GFP_KERNEL_ACCOUNT);
-track_free:
- kvm_page_track_free_memslot(slot);
- return -ENOMEM;
+ return slot->arch.gfn_write_track ? 0 : -ENOMEM;
}
-static inline bool page_track_mode_is_valid(enum kvm_page_track_mode mode)
+int kvm_page_track_create_memslot(struct kvm *kvm,
+ struct kvm_memory_slot *slot,
+ unsigned long npages)
{
- if (mode < 0 || mode >= KVM_PAGE_TRACK_MAX)
- return false;
+ if (!kvm_page_track_write_tracking_enabled(kvm))
+ return 0;
- return true;
+ return __kvm_page_track_write_tracking_alloc(slot, npages);
}
int kvm_page_track_write_tracking_alloc(struct kvm_memory_slot *slot)
{
- unsigned short *gfn_track;
-
- if (slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE])
- return 0;
-
- gfn_track = __vcalloc(slot->npages, sizeof(*gfn_track),
- GFP_KERNEL_ACCOUNT);
- if (gfn_track == NULL)
- return -ENOMEM;
-
- slot->arch.gfn_track[KVM_PAGE_TRACK_WRITE] = gfn_track;
- return 0;
+ return __kvm_page_track_write_tracking_alloc(slot, slot->npages);
}
-static void update_gfn_track(struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode, short count)
+static void update_gfn_write_track(struct kvm_memory_slot *slot, gfn_t gfn,
+ short count)
{
int index, val;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
- val = slot->arch.gfn_track[mode][index];
+ val = slot->arch.gfn_write_track[index];
- if (WARN_ON(val + count < 0 || val + count > USHRT_MAX))
+ if (WARN_ON_ONCE(val + count < 0 || val + count > USHRT_MAX))
return;
- slot->arch.gfn_track[mode][index] += count;
+ slot->arch.gfn_write_track[index] += count;
}
-/*
- * add guest page to the tracking pool so that corresponding access on that
- * page will be intercepted.
- *
- * It should be called under the protection both of mmu-lock and kvm->srcu
- * or kvm->slots_lock.
- *
- * @kvm: the guest instance we are interested in.
- * @slot: the @gfn belongs to.
- * @gfn: the guest page.
- * @mode: tracking mode, currently only write track is supported.
- */
-void kvm_slot_page_track_add_page(struct kvm *kvm,
- struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode)
+void __kvm_write_track_add_gfn(struct kvm *kvm, struct kvm_memory_slot *slot,
+ gfn_t gfn)
{
+ lockdep_assert_held_write(&kvm->mmu_lock);
- if (WARN_ON(!page_track_mode_is_valid(mode)))
- return;
+ lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
+ srcu_read_lock_held(&kvm->srcu));
- if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm)))
+ if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
return;
- update_gfn_track(slot, gfn, mode, 1);
+ update_gfn_write_track(slot, gfn, 1);
/*
* new track stops large page mapping for the
*/
kvm_mmu_gfn_disallow_lpage(slot, gfn);
- if (mode == KVM_PAGE_TRACK_WRITE)
- if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
- kvm_flush_remote_tlbs(kvm);
+ if (kvm_mmu_slot_gfn_write_protect(kvm, slot, gfn, PG_LEVEL_4K))
+ kvm_flush_remote_tlbs(kvm);
}
-EXPORT_SYMBOL_GPL(kvm_slot_page_track_add_page);
-/*
- * remove the guest page from the tracking pool which stops the interception
- * of corresponding access on that page. It is the opposed operation of
- * kvm_slot_page_track_add_page().
- *
- * It should be called under the protection both of mmu-lock and kvm->srcu
- * or kvm->slots_lock.
- *
- * @kvm: the guest instance we are interested in.
- * @slot: the @gfn belongs to.
- * @gfn: the guest page.
- * @mode: tracking mode, currently only write track is supported.
- */
-void kvm_slot_page_track_remove_page(struct kvm *kvm,
- struct kvm_memory_slot *slot, gfn_t gfn,
- enum kvm_page_track_mode mode)
+void __kvm_write_track_remove_gfn(struct kvm *kvm,
+ struct kvm_memory_slot *slot, gfn_t gfn)
{
- if (WARN_ON(!page_track_mode_is_valid(mode)))
- return;
+ lockdep_assert_held_write(&kvm->mmu_lock);
- if (WARN_ON(mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm)))
+ lockdep_assert_once(lockdep_is_held(&kvm->slots_lock) ||
+ srcu_read_lock_held(&kvm->srcu));
+
+ if (KVM_BUG_ON(!kvm_page_track_write_tracking_enabled(kvm), kvm))
return;
- update_gfn_track(slot, gfn, mode, -1);
+ update_gfn_write_track(slot, gfn, -1);
/*
* allow large page mapping for the tracked page
*/
kvm_mmu_gfn_allow_lpage(slot, gfn);
}
-EXPORT_SYMBOL_GPL(kvm_slot_page_track_remove_page);
/*
* check if the corresponding access on the specified guest page is tracked.
*/
-bool kvm_slot_page_track_is_active(struct kvm *kvm,
- const struct kvm_memory_slot *slot,
- gfn_t gfn, enum kvm_page_track_mode mode)
+bool kvm_gfn_is_write_tracked(struct kvm *kvm,
+ const struct kvm_memory_slot *slot, gfn_t gfn)
{
int index;
- if (WARN_ON(!page_track_mode_is_valid(mode)))
- return false;
-
if (!slot)
return false;
- if (mode == KVM_PAGE_TRACK_WRITE &&
- !kvm_page_track_write_tracking_enabled(kvm))
+ if (!kvm_page_track_write_tracking_enabled(kvm))
return false;
index = gfn_to_index(gfn, slot->base_gfn, PG_LEVEL_4K);
- return !!READ_ONCE(slot->arch.gfn_track[mode][index]);
+ return !!READ_ONCE(slot->arch.gfn_write_track[index]);
}
+#ifdef CONFIG_KVM_EXTERNAL_WRITE_TRACKING
void kvm_page_track_cleanup(struct kvm *kvm)
{
struct kvm_page_track_notifier_head *head;
* register the notifier so that event interception for the tracked guest
* pages can be received.
*/
-void
-kvm_page_track_register_notifier(struct kvm *kvm,
- struct kvm_page_track_notifier_node *n)
+int kvm_page_track_register_notifier(struct kvm *kvm,
+ struct kvm_page_track_notifier_node *n)
{
struct kvm_page_track_notifier_head *head;
+ if (!kvm || kvm->mm != current->mm)
+ return -ESRCH;
+
+ kvm_get_kvm(kvm);
+
head = &kvm->arch.track_notifier_head;
write_lock(&kvm->mmu_lock);
hlist_add_head_rcu(&n->node, &head->track_notifier_list);
write_unlock(&kvm->mmu_lock);
+ return 0;
}
EXPORT_SYMBOL_GPL(kvm_page_track_register_notifier);
* stop receiving the event interception. It is the opposed operation of
* kvm_page_track_register_notifier().
*/
-void
-kvm_page_track_unregister_notifier(struct kvm *kvm,
- struct kvm_page_track_notifier_node *n)
+void kvm_page_track_unregister_notifier(struct kvm *kvm,
+ struct kvm_page_track_notifier_node *n)
{
struct kvm_page_track_notifier_head *head;
hlist_del_rcu(&n->node);
write_unlock(&kvm->mmu_lock);
synchronize_srcu(&head->track_srcu);
+
+ kvm_put_kvm(kvm);
}
EXPORT_SYMBOL_GPL(kvm_page_track_unregister_notifier);
* The node should figure out if the written page is the one that node is
* interested in by itself.
*/
-void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
- int bytes)
+void __kvm_page_track_write(struct kvm *kvm, gpa_t gpa, const u8 *new, int bytes)
{
struct kvm_page_track_notifier_head *head;
struct kvm_page_track_notifier_node *n;
int idx;
- head = &vcpu->kvm->arch.track_notifier_head;
+ head = &kvm->arch.track_notifier_head;
if (hlist_empty(&head->track_notifier_list))
return;
idx = srcu_read_lock(&head->track_srcu);
hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
- srcu_read_lock_held(&head->track_srcu))
+ srcu_read_lock_held(&head->track_srcu))
if (n->track_write)
- n->track_write(vcpu, gpa, new, bytes, n);
+ n->track_write(gpa, new, bytes, n);
srcu_read_unlock(&head->track_srcu, idx);
}
/*
- * Notify the node that memory slot is being removed or moved so that it can
- * drop write-protection for the pages in the memory slot.
- *
- * The node should figure out it has any write-protected pages in this slot
- * by itself.
+ * Notify external page track nodes that a memory region is being removed from
+ * the VM, e.g. so that users can free any associated metadata.
*/
-void kvm_page_track_flush_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
+void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot)
{
struct kvm_page_track_notifier_head *head;
struct kvm_page_track_notifier_node *n;
idx = srcu_read_lock(&head->track_srcu);
hlist_for_each_entry_srcu(n, &head->track_notifier_list, node,
- srcu_read_lock_held(&head->track_srcu))
- if (n->track_flush_slot)
- n->track_flush_slot(kvm, slot, n);
+ srcu_read_lock_held(&head->track_srcu))
+ if (n->track_remove_region)
+ n->track_remove_region(slot->base_gfn, slot->npages, n);
srcu_read_unlock(&head->track_srcu, idx);
}
+
+/*
+ * add guest page to the tracking pool so that corresponding access on that
+ * page will be intercepted.
+ *
+ * @kvm: the guest instance we are interested in.
+ * @gfn: the guest page.
+ */
+int kvm_write_track_add_gfn(struct kvm *kvm, gfn_t gfn)
+{
+ struct kvm_memory_slot *slot;
+ int idx;
+
+ idx = srcu_read_lock(&kvm->srcu);
+
+ slot = gfn_to_memslot(kvm, gfn);
+ if (!slot) {
+ srcu_read_unlock(&kvm->srcu, idx);
+ return -EINVAL;
+ }
+
+ write_lock(&kvm->mmu_lock);
+ __kvm_write_track_add_gfn(kvm, slot, gfn);
+ write_unlock(&kvm->mmu_lock);
+
+ srcu_read_unlock(&kvm->srcu, idx);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_track_add_gfn);
+
+/*
+ * remove the guest page from the tracking pool which stops the interception
+ * of corresponding access on that page.
+ *
+ * @kvm: the guest instance we are interested in.
+ * @gfn: the guest page.
+ */
+int kvm_write_track_remove_gfn(struct kvm *kvm, gfn_t gfn)
+{
+ struct kvm_memory_slot *slot;
+ int idx;
+
+ idx = srcu_read_lock(&kvm->srcu);
+
+ slot = gfn_to_memslot(kvm, gfn);
+ if (!slot) {
+ srcu_read_unlock(&kvm->srcu, idx);
+ return -EINVAL;
+ }
+
+ write_lock(&kvm->mmu_lock);
+ __kvm_write_track_remove_gfn(kvm, slot, gfn);
+ write_unlock(&kvm->mmu_lock);
+
+ srcu_read_unlock(&kvm->srcu, idx);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_write_track_remove_gfn);
+#endif
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