KVM: PPC: Book3s HV: Implement get_dirty_log using hardware changed bit
This changes the implementation of kvm_vm_ioctl_get_dirty_log() for
Book3s HV guests to use the hardware C (changed) bits in the guest
hashed page table. Since this makes the implementation quite different
from the Book3s PR case, this moves the existing implementation from
book3s.c to book3s_pr.c and creates a new implementation in book3s_hv.c.
That implementation calls kvmppc_hv_get_dirty_log() to do the actual
work by calling kvm_test_clear_dirty on each page. It iterates over
the HPTEs, clearing the C bit if set, and returns 1 if any C bit was
set (including the saved C bit in the rmap entry).
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 86c4191..0f1ddf0 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -1072,6 +1072,43 @@
return fd;
}
+/*
+ * Get (and clear) the dirty memory log for a memory slot.
+ */
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
+{
+ struct kvm_memory_slot *memslot;
+ int r;
+ unsigned long n;
+
+ mutex_lock(&kvm->slots_lock);
+
+ r = -EINVAL;
+ if (log->slot >= KVM_MEMORY_SLOTS)
+ goto out;
+
+ memslot = id_to_memslot(kvm->memslots, log->slot);
+ r = -ENOENT;
+ if (!memslot->dirty_bitmap)
+ goto out;
+
+ n = kvm_dirty_bitmap_bytes(memslot);
+ memset(memslot->dirty_bitmap, 0, n);
+
+ r = kvmppc_hv_get_dirty_log(kvm, memslot);
+ if (r)
+ goto out;
+
+ r = -EFAULT;
+ if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
+ goto out;
+
+ r = 0;
+out:
+ mutex_unlock(&kvm->slots_lock);
+ return r;
+}
+
static unsigned long slb_pgsize_encoding(unsigned long psize)
{
unsigned long senc = 0;