This isn't really a bug.  Using -i disk causes virt-v2v to guess
some basic metadata about the guest.  If you have actual metadata
(eg. libvirt XML) then you should use the -i libvirtxml method instead
(or in this case -i libvirt, since the guest comes from libvirt).

https://github.com/libguestfs/libguestfs/blob/master/v2v/input_disk.ml#L95-L110

(In reply to Richard W.M. Jones from comment #1)
> This isn't really a bug.  Using -i disk causes virt-v2v to guess
> some basic metadata about the guest.  If you have actual metadata
> (eg. libvirt XML) then you should use the -i libvirtxml method instead
> (or in this case -i libvirt, since the guest comes from libvirt).
> 
> https://github.com/libguestfs/libguestfs/blob/master/v2v/input_disk.ml#L95-
> L110

Yes,when I use -i libvirt or -i libvirtxml,it can keep the original graphics type.

For -i disk,it causes virt-v2v to guess some basic metadata about the guest,for graphics,sdl is deprecated on both rhel6 and rhel7,so for -i libvirt,if the original guest has graphics type as sdl,v2v change it to vnc or spice which are supported on rhel6/rhel7.

Can we just deal with the same way for -i disk with -i libvirt?

I suppose we can change the default *downstream*.

diff --git a/v2v/input_disk.ml b/v2v/input_disk.ml
index 3926602..9599178 100644
--- a/v2v/input_disk.ml
+++ b/v2v/input_disk.ml
@@ -100,7 +100,7 @@ class input_disk input_format disk = object
       s_features = [ "acpi"; "apic"; "pae" ];
       s_firmware = UnknownFirmware;       (* causes virt-v2v to autodetect *)
       s_display =
-        Some { s_display_type = Window; s_keymap = None; s_password = None;
+        Some { s_display_type = VNC; s_keymap = None; s_password = None;
                s_listen = LNone; s_port = None };
       s_video = None;
       s_sound = None;

*** Bug 1365831 has been marked as a duplicate of this bug. ***

I can reproduce the bug with below builds:
virt-v2v-1.32.7-3.el7.x86_64
libvirt-2.0.0-10.el7.x86_64

Reproduce steps:
1.Prepare a guest with spice graphics type.
2.Use virt-v2v -i disk to convert the disk.
## virt-v2v -i disk  /var/lib/libvirt/images/rhel7.2.qcow2  -on rhel72
[   0.0] Opening the source -i disk /var/lib/libvirt/images/rhel7.2.qcow2
[   0.1] Creating an overlay to protect the source from being modified
[   0.5] Initializing the target -o libvirt -os default
[   0.5] Opening the overlay
[   5.0] Inspecting the overlay
[  14.1] Checking for sufficient free disk space in the guest
[  14.1] Estimating space required on target for each disk
[  14.1] Converting Red Hat Enterprise Linux Server 7.2 (Maipo) to run on KVM
virt-v2v: warning: /files/boot/grub2/device.map/hd1 references unknown 
device "sdb".  You may have to fix this entry manually after conversion.
virt-v2v: warning: /files/boot/grub2/device.map/hd3 references unknown 
device "sdb".  You may have to fix this entry manually after conversion.
virt-v2v: This guest has virtio drivers installed.
[ 114.8] Mapping filesystem data to avoid copying unused and blank areas
[ 115.2] Closing the overlay
[ 116.5] Checking if the guest needs BIOS or UEFI to boot
[ 116.5] Assigning disks to buses
[ 116.5] Copying disk 1/1 to /var/lib/libvirt/images/rhel72-sda (qcow2)
    (100.00/100%)
[ 177.3] Creating output metadata
Pool default refreshed

3.After conversion ,check the xml file of the guest.
#virsh dumpxml rhel72
*********  
 <graphics type='sdl'/>
    <video>
      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
    </video>
**********
4.After conversion,try to boot the guest.
# virsh start rhel72
error: Failed to start domain rhel72
error: internal error: process exited while connecting to monitor: qemu-kvm: -sdl: SDL support is disabled

Verify the bug with builds:
virt-v2v-1.36.2-1.el7.x86_64
libguestfs-1.36.2-1.el7.x86_64
libvirt-3.1.0-2.el7.x86_64
qemu-kvm-rhev-2.8.0-6.el7.x86_64
libguestfs-winsupport-7.2-2.el7.x86_64
virtio-win-1.9.0-3.el7.noarch

Steps:
Scenario1:
1.Convert a windows guest which has graphic mode spice+VGA

2.Use virt-v2v -i disk to convert this guest disk 
# virt-v2v -i disk win2016.qcow2 -on win2016-bug1372671

3.Check the graphic part xml of guest "win2016-bug1372671" after finishing the virt-v2v conversion, the graphic mode is correct 

# virsh dumpxml win2016-bug1372671 |grep graphic -A 2
    <graphics type='vnc' port='5900' autoport='yes' listen='127.0.0.1'>
      <listen type='address' address='127.0.0.1'/>
    </graphics>
    <video>
      <model type='cirrus' vram='16384' heads='1' primary='yes'/>

4.Power on the guest and checkpoints of guest are passed

Scenario2:
1.Convert a linux guest which has graphic mode spice+qxl

2.Use virt-v2v -i disk to convert this guest disk 
# virt-v2v -i disk rhel7.3.qcow2 -on rhel7.3-mxie

3.Check the graphic part xml of guest after finishing the virt-v2v conversion, the graphic mode is correct 
# virsh dumpxml rhel7.3-mxie |grep graphic -A 2
    <graphics type='vnc' port='-1' autoport='yes'>
      <listen type='address'/>
    </graphics>
    <video>
      <model type='qxl' ram='65536' vram='65536' vgamem='16384' heads='1' primary='yes'/>

4.Power on the guest and checkpoints of guest are passed


According to above verify result, the bug has been fixed 

So move the bug from ON_QA to VERIFIED

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:2023