staging: unable to restore HVM with Viridian param set

[Tamas K Lengyel <tamas.k.lengyel@xxxxxxxxx>]

Hi all,
trying to restore a Windows VM saved on Xen 4.14 with Xen staging results in:

# xl restore -p /shared/cfg/windows10.save
Loading new save file /shared/cfg/windows10.save (new xl fmt info 0x3/0x0/1475)
 Savefile contains xl domain config in JSON format
Parsing config from <saved>
xc: info: Found x86 HVM domain from Xen 4.14
xc: info: Restoring domain
xc: error: set HVM param 9 = 0x0000000000000065 (17 = File exists):
Internal error
xc: error: Restore failed (17 = File exists): Internal error
libxl: error: libxl_stream_read.c:850:libxl__xc_domain_restore_done:
restoring domain: File exists
libxl: error: libxl_create.c:1581:domcreate_rebuild_done: Domain
8:cannot (re-)build domain: -3
libxl: error: libxl_domain.c:1182:libxl__destroy_domid: Domain
8:Non-existant domain
libxl: error: libxl_domain.c:1136:domain_destroy_callback: Domain
8:Unable to destroy guest
libxl: error: libxl_domain.c:1063:domain_destroy_cb: Domain
8:Destruction of domain failed

Running on staging 419cd07895891c6642f29085aee07be72413f08c

Tamas