- support QEMU interface for initial VM Write Protect
- QEMU Dirty bit map log retrieval


Signed-off-by: Mario Smarduch <m.smard...@samsung.com>
---
 arch/arm/kvm/arm.c |   62 +++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 61 insertions(+), 1 deletion(-)

diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
index bd18bb8..9076e3d 100644
--- a/arch/arm/kvm/arm.c
+++ b/arch/arm/kvm/arm.c
@@ -241,6 +241,8 @@ void kvm_arch_commit_memory_region(struct kvm *kvm,
                                   const struct kvm_memory_slot *old,
                                   enum kvm_mr_change change)
 {
+       if ((change != KVM_MR_DELETE) && (mem->flags & KVM_MEM_LOG_DIRTY_PAGES))
+               kvm_mmu_slot_remove_write_access(kvm, mem->slot);
 }
 
 void kvm_arch_flush_shadow_all(struct kvm *kvm)
@@ -773,9 +775,67 @@ long kvm_arch_vcpu_ioctl(struct file *filp,
        }
 }
 
+/*
+ * Walks the memslot dirty bitmap, write protects dirty pages for next rount,
+ * and stores the dirty bitmap fo QEMU retrieval.
+ *
+ */
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm, struct kvm_dirty_log *log)
 {
-       return -EINVAL;
+       int r;
+       struct kvm_memory_slot *memslot;
+       unsigned long n, i;
+       unsigned long *dirty_bitmap;
+       unsigned long *dirty_bitmap_buffer;
+       bool is_dirty = false;
+       gfn_t offset;
+
+       mutex_lock(&kvm->slots_lock);
+       r = -EINVAL;
+
+       if (log->slot >= KVM_USER_MEM_SLOTS)
+               goto out;
+
+       memslot = id_to_memslot(kvm->memslots, log->slot);
+       dirty_bitmap = memslot->dirty_bitmap;
+
+       r = -ENOENT;
+       if (!dirty_bitmap)
+               goto out;
+
+       n = kvm_dirty_bitmap_bytes(memslot);
+       dirty_bitmap_buffer = dirty_bitmap + n / sizeof(long);
+       memset(dirty_bitmap_buffer, 0, n);
+
+       spin_lock(&kvm->mmu_lock);
+       for (i = 0; i < n / sizeof(long); i++) {
+               unsigned long mask;
+
+               if (!dirty_bitmap[i])
+                       continue;
+
+               is_dirty = true;
+               offset = i * BITS_PER_LONG;
+               kvm_mmu_write_protect_pt_masked(kvm, memslot, offset,
+                                                       dirty_bitmap[i]);
+               mask = dirty_bitmap[i];
+               dirty_bitmap_buffer[i] = mask;
+               dirty_bitmap[i] = 0;
+       }
+
+       if (is_dirty)
+               kvm_tlb_flush_vmid(kvm);
+
+       spin_unlock(&kvm->mmu_lock);
+       r = -EFAULT;
+
+       if (copy_to_user(log->dirty_bitmap, dirty_bitmap_buffer, n))
+               goto out;
+
+       r = 0;
+out:
+       mutex_unlock(&kvm->slots_lock);
+       return r;
 }
 
 static int kvm_vm_ioctl_set_device_addr(struct kvm *kvm,
-- 
1.7.9.5

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