[v12,25/77] KVM: x86: page track: add track_create_slot() callback

Commit Message

Adalbert Lazăr Oct. 6, 2021, 5:30 p.m. UTC

From: Mihai Donțu <[e-mail]>

This is used to add page access notifications as soon as a slot appears
or when a slot is moved.

Signed-off-by: Mihai Donțu <[e-mail]>
Signed-off-by: Adalbert Lazăr <[e-mail]>
---
 arch/x86/include/asm/kvm_page_track.h | 11 +++++++++++
 arch/x86/kvm/mmu/page_track.c         | 15 +++++++++++++++
 2 files changed, 26 insertions(+)

Patch

diff --git a/arch/x86/include/asm/kvm_page_track.h b/arch/x86/include/asm/kvm_page_track.h
index f981b6360de5..df6e5674ea5c 100644
--- a/arch/x86/include/asm/kvm_page_track.h
+++ b/arch/x86/include/asm/kvm_page_track.h
@@ -36,6 +36,17 @@  struct kvm_page_track_notifier_node {
 	void (*track_write)(struct kvm_vcpu *vcpu, gpa_t gpa, gva_t gva,
 			    const u8 *new, int bytes,
 			    struct kvm_page_track_notifier_node *node);
+	/*
+	 * It is called when memory slot is being created
+	 *
+	 * @kvm: the kvm where memory slot being moved or removed
+	 * @slot: the memory slot being moved or removed
+	 * @npages: the number of pages
+	 * @node: this node
+	 */
+	void (*track_create_slot)(struct kvm *kvm, struct kvm_memory_slot *slot,
+				  unsigned long npages,
+				  struct kvm_page_track_notifier_node *node);
 	/*
 	 * It is called when memory slot is being moved or removed
 	 * users can drop write-protection for the pages in that memory slot
diff --git a/arch/x86/kvm/mmu/page_track.c b/arch/x86/kvm/mmu/page_track.c
index e0b1cdd3013e..f18be17b56a3 100644
--- a/arch/x86/kvm/mmu/page_track.c
+++ b/arch/x86/kvm/mmu/page_track.c
@@ -43,6 +43,9 @@  int kvm_page_track_create_memslot(struct kvm *kvm,
 				  struct kvm_memory_slot *slot,
 				  unsigned long npages)
 {
+	struct kvm_page_track_notifier_head *head;
+	struct kvm_page_track_notifier_node *n;
+	int idx;
 	int i;
 
 	for (i = 0; i < KVM_PAGE_TRACK_MAX; i++) {
@@ -56,6 +59,18 @@  int kvm_page_track_create_memslot(struct kvm *kvm,
 			goto track_free;
 	}
 
+	head = &kvm->arch.track_notifier_head;
+
+	if (hlist_empty(&head->track_notifier_list))
+		return 0;
+
+	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_create_slot)
+			n->track_create_slot(kvm, slot, npages, n);
+	srcu_read_unlock(&head->track_srcu, idx);
+
 	return 0;
 
 track_free: