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-rw-r--r--include/linux/kvm_dirty_ring.h103
-rw-r--r--include/linux/kvm_host.h13
2 files changed, 116 insertions, 0 deletions
diff --git a/include/linux/kvm_dirty_ring.h b/include/linux/kvm_dirty_ring.h
new file mode 100644
index 000000000000..120e5e90fa1d
--- /dev/null
+++ b/include/linux/kvm_dirty_ring.h
@@ -0,0 +1,103 @@
+#ifndef KVM_DIRTY_RING_H
+#define KVM_DIRTY_RING_H
+
+#include <linux/kvm.h>
+
+/**
+ * kvm_dirty_ring: KVM internal dirty ring structure
+ *
+ * @dirty_index: free running counter that points to the next slot in
+ * dirty_ring->dirty_gfns, where a new dirty page should go
+ * @reset_index: free running counter that points to the next dirty page
+ * in dirty_ring->dirty_gfns for which dirty trap needs to
+ * be reenabled
+ * @size: size of the compact list, dirty_ring->dirty_gfns
+ * @soft_limit: when the number of dirty pages in the list reaches this
+ * limit, vcpu that owns this ring should exit to userspace
+ * to allow userspace to harvest all the dirty pages
+ * @dirty_gfns: the array to keep the dirty gfns
+ * @index: index of this dirty ring
+ */
+struct kvm_dirty_ring {
+ u32 dirty_index;
+ u32 reset_index;
+ u32 size;
+ u32 soft_limit;
+ struct kvm_dirty_gfn *dirty_gfns;
+ int index;
+};
+
+#if (KVM_DIRTY_LOG_PAGE_OFFSET == 0)
+/*
+ * If KVM_DIRTY_LOG_PAGE_OFFSET not defined, kvm_dirty_ring.o should
+ * not be included as well, so define these nop functions for the arch.
+ */
+static inline u32 kvm_dirty_ring_get_rsvd_entries(void)
+{
+ return 0;
+}
+
+static inline int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring,
+ int index, u32 size)
+{
+ return 0;
+}
+
+static inline struct kvm_dirty_ring *kvm_dirty_ring_get(struct kvm *kvm)
+{
+ return NULL;
+}
+
+static inline int kvm_dirty_ring_reset(struct kvm *kvm,
+ struct kvm_dirty_ring *ring)
+{
+ return 0;
+}
+
+static inline void kvm_dirty_ring_push(struct kvm_dirty_ring *ring,
+ u32 slot, u64 offset)
+{
+}
+
+static inline struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring,
+ u32 offset)
+{
+ return NULL;
+}
+
+static inline void kvm_dirty_ring_free(struct kvm_dirty_ring *ring)
+{
+}
+
+static inline bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring)
+{
+ return true;
+}
+
+#else /* KVM_DIRTY_LOG_PAGE_OFFSET == 0 */
+
+u32 kvm_dirty_ring_get_rsvd_entries(void);
+int kvm_dirty_ring_alloc(struct kvm_dirty_ring *ring, int index, u32 size);
+struct kvm_dirty_ring *kvm_dirty_ring_get(struct kvm *kvm);
+
+/*
+ * called with kvm->slots_lock held, returns the number of
+ * processed pages.
+ */
+int kvm_dirty_ring_reset(struct kvm *kvm, struct kvm_dirty_ring *ring);
+
+/*
+ * returns =0: successfully pushed
+ * <0: unable to push, need to wait
+ */
+void kvm_dirty_ring_push(struct kvm_dirty_ring *ring, u32 slot, u64 offset);
+
+/* for use in vm_operations_struct */
+struct page *kvm_dirty_ring_get_page(struct kvm_dirty_ring *ring, u32 offset);
+
+void kvm_dirty_ring_free(struct kvm_dirty_ring *ring);
+bool kvm_dirty_ring_soft_full(struct kvm_dirty_ring *ring);
+
+#endif /* KVM_DIRTY_LOG_PAGE_OFFSET == 0 */
+
+#endif /* KVM_DIRTY_RING_H */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ca7c1459a8e3..864b156391c8 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -34,6 +34,7 @@
#include <linux/kvm_types.h>
#include <asm/kvm_host.h>
+#include <linux/kvm_dirty_ring.h>
#ifndef KVM_MAX_VCPU_ID
#define KVM_MAX_VCPU_ID KVM_MAX_VCPUS
@@ -319,6 +320,7 @@ struct kvm_vcpu {
bool preempted;
bool ready;
struct kvm_vcpu_arch arch;
+ struct kvm_dirty_ring dirty_ring;
};
static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu)
@@ -505,6 +507,7 @@ struct kvm {
struct srcu_struct irq_srcu;
pid_t userspace_pid;
unsigned int max_halt_poll_ns;
+ u32 dirty_ring_size;
};
#define kvm_err(fmt, ...) \
@@ -1477,4 +1480,14 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu *vcpu)
}
#endif /* CONFIG_KVM_XFER_TO_GUEST_WORK */
+/*
+ * This defines how many reserved entries we want to keep before we
+ * kick the vcpu to the userspace to avoid dirty ring full. This
+ * value can be tuned to higher if e.g. PML is enabled on the host.
+ */
+#define KVM_DIRTY_RING_RSVD_ENTRIES 64
+
+/* Max number of entries allowed for each kvm dirty ring */
+#define KVM_DIRTY_RING_MAX_ENTRIES 65536
+
#endif