virt/kvm/dirty_ring.c

3  * KVM dirty ring implementation
38 static u32 kvm_dirty_ring_used(struct kvm_dirty_ring *ring)
40 	return READ_ONCE(ring->dirty_index) - READ_ONCE(ring->reset_index);
43 static bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring)
45 	return kvm_dirty_ring_used(ring) >= ring->soft_limit;
48 static bool kvm_dirty_ring_full(struct kvm_dirty_ring *ring)
50 	return kvm_dirty_ring_used(ring) >= ring->size;
74 int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size)
76 	ring->dirty_gfns = vzalloc(size);
77 	if (!ring->dirty_gfns)
80 	ring->size = size / sizeof(struct kvm_dirty_gfn);
81 	ring->soft_limit = ring->size - kvm_dirty_ring_get_rsvd_entries();
82 	ring->dirty_index = 0;
83 	ring->reset_index = 0;
84 	ring->index = index;
104 int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring)
117 		entry = &ring->dirty_gfns[ring->reset_index & (ring->size - 1)];
128 		ring->reset_index++;
164 	trace_kvm_dirty_ring_reset(ring);
171 	struct kvm_dirty_ring *ring = &vcpu->dirty_ring;
175 	WARN_ON_ONCE(kvm_dirty_ring_full(ring));
177 	entry = &ring->dirty_gfns[ring->dirty_index & (ring->size - 1)];
187 	ring->dirty_index++;
188 	trace_kvm_dirty_ring_push(ring, slot, offset);
190 	if (kvm_dirty_ring_soft_full(ring))
197 	 * The VCPU isn't runnable when the dirty ring becomes soft full.
200 	 * the dirty ring is reset by userspace.
213 struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset)
215 	return vmalloc_to_page((void *)ring->dirty_gfns + offset * PAGE_SIZE);
218 void kvm_dirty_ring_free(struct kvm_dirty_ring *ring)
220 	vfree(ring->dirty_gfns);
221 	ring->dirty_gfns = NULL;