Rangeley C2758: missed IOMMU support for Xen Dom0

Hello,

Could you please help me understand what and were i did wrong?  

Running a FreeBSD 12.0-CURRENT-r318425 GENERIC-NODEBUG and trying to install Xen Dom0 (xen-4.7.0_2 from ports).

HW setup:
Supermicro A1SRM-2758F [Intel Rangeley Atom processor C2758]
Motherboard spec: http://supermicro.com/products/motherboard/Atom/X10/A1SRM-2758F.cfm
CPU spec: https://ark.intel.com/products/77988/Intel-Atom-Processor-C2758-4M-Cache-2_40-GHz

loader.conf:
hw.pci.mcfg=0
xen_kernel="/boot/xen"
xen_cmdline="dom0_mem=2048M dom0_max_vcpus=4 dom0pvh=1 com1=115200,8n1 com2=115200,8n1 console=com2 guest_loglvl=all loglvl=all"

Xen Dom0 boot failed with error
Full boot log - https://cloud.deiter.ru/index.php/s/bg5lQSjPPSkiTAq

...
(XEN) I/O virtualisation disabled
...
(XEN) ****************************************
(XEN) Panic on CPU 0:
(XEN) Presently, iommu must be enabled for PVH hardware domain
(XEN)
(XEN) ****************************************
 

Boot without Xen kernel is OK
Full boot log - https://cloud.deiter.ru/index.php/s/lUXLPnPSTWqqQNO

...
CPU: Intel(R) Atom(TM) CPU  C2758  _at_ 2.40GHz (2400.06-MHz K8-class CPU)
  Origin="GenuineIntel"  Id=0x406d8  Family=0x6  Model=0x4d  Stepping=8
  Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x43d8e3bf<SSE3,PCLMULQDQ,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,SSE4.2,MOVBE,POPCNT,TSCDLT,AESNI,RDRAND>
  AMD Features=0x28100800<SYSCALL,NX,RDTSCP,LM>
  AMD Features2=0x101<LAHF,Prefetch>
  Structured Extended Features=0x2282<TSCADJ,SMEP,ERMS,NFPUSG>
  VT-x: Basic Features=0xda0400<SMM,INS/OUTS,TRUE>
        Pin-Based Controls=0x7f<ExtINT,NMI,VNMI,PreTmr>
        Primary Processor Controls=0xfff9fffe<INTWIN,TSCOff,HLT,INVLPG,MWAIT,RDPMC,RDTSC,CR3-LD,CR3-ST,CR8-LD,CR8-ST,TPR,NMIWIN,MOV-DR,IO,IOmap,MTF,MSRmap,MONITOR,PAUSE>
        Secondary Processor Controls=0x28ef<APIC,EPT,DT,RDTSCP,VPID,WBINVD,UG,RDRAND,VMFUNC>
        Exit Controls=0xda0400<PAT-LD,EFER-SV,PTMR-SV>
        Entry Controls=0xda0400
        EPT Features=0x6114141<XO,PW4,UC,WB,2M,INVEPT,single,all>
        VPID Features=0xf01<INVVPID,individual,single,all,single-globals>
...
pci0: <base peripheral, IOMMU> at device 15.0 (no driver attached)
pci0: <base peripheral> at device 19.0 (no driver attached)
...

# pciconf -lv
none1_at_pci0:0:15:0:      class=0x080600 card=0x082015d9 chip=0x1f168086 rev=0x02 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = 'Atom processor C2000 RCEC'
    class      = base peripheral
    subclass   = IOMMU


Thank you!

Alex Deiter
alex.deiter_at_gmail.com