black screen troubles trying to boot with Xen Hypervisor grub option

[Jamie Campbell <jamie@xxxxxxxx>]

I'm trying to work my way through the beginner guide ( 
https://wiki.xenproject.org/wiki/Xen_Project_Beginners_Guide ). Things 
seem fine all the way down to step 5 "Installing the Xen Project 
Software".  I do the reboot and select the option with Xen Hypervisor 
and instead of getting a console login I get a black screen.  The 
machine doesn't have a serial port or SOL so I took the suggestion on 
the serial console page saying "you could always record a video of the 
boot process".  Then I transcribed it (which means there might be some 
typos).  From my limited understanding the log seems to have some 
warnings and suggestions about possible changes to make things better, 
but nothing that seems to indicate I'm about to be dumped into a black 
screen.  Log below:
-----------------------------

(XEN) ACPI: 32/64X FACS address mismatch in FADT - 
daf5a000/0000000000000000, using 32
(XEN) IOAPIC[0]: apic_id 2, version 32, address 0xfec00000, GSI 0-23
(XEN) PCI: Not using MCFG for segment 0000 bus 00-3f
(XEN) Switched to APIC driver x2apic_cluster
(XEN) CPU0: 1200 ... 2600 MHz
(XEN) xstate: size: 0x340 and states: 0x7
(XEN) Speculative mitigation facilities:
(XEN)   Hardware hints:
(XEN)   Hardware features:
(XEN)   Compiled-in support: INDIRECT_THUNK SHADOW_PAGING
(XEN)   Xen settings: BTI-Thunk RETPOLINE, SPEC_CTRL: No, Other: 
BRANCH_HARDEN
(XEN)   L1TF: believed vulnerable, maxphysaddr L1D 46, CPUID 36, Safe 
address 1000000000
(XEN)   Support for HVM VMs: RSB EAGER_FPU
(XEN)   XPTI (64-bit PV only): Dom0 enabled, DomU enabled (without PCID)
(XEN)   PV L1TF shadowing: Dom0 disabled, DomU enabled
(XEN) Using scheduler: SMP Credit Scheduler rev2 (credit2)
(XEN) Initializing Credit2 scheduler
(XEN) Platform timer is 14.318MHz HPET
(XEN) Detected 2594.107 MHz processor.
(XEN) Intel VT-d iommu 0 supported page sizes: 4kB
(XEN) Intel VT-d iommu 1 supported page sizes: 4kB
(XEN) Intel VT-d Snoop Control not enabled.
(XEN) Intel VT-d Dom0 DMA Passthrough not enabled.
(XEN) Intel VT-d Queued Invalidation enabled.
(XEN) Intel VT-d Interrupt Remapping enabled.
(XEN) Intel VT-d Posted Interrupt not enabled.
(XEN) Intel VT-d Shared EPT tabled not enabled.
(XEN) I/O virtualization enabled
(XEN)  - Dom0 mode: Relaxed
(XEN) Interrupt remapping enabled
(XEN) Enabled directed EOI with ioapic_ack_old on!
(XEN) Enabling APIC mode: Clustered. Using 1 I/O APICs
(XEN) ENABLING IO-APIC IRQs
(XEN)  -> Using old ACK method
(XEN) Allocated console ring of 16 KiB.
(XEN) VMX: Supported advanced features:
(XEN)  - APIC MMIO access virtualisation
(XEN)  - APIC TPR shadow
(XEN)  - Extended Page Tables (EPT)
(XEN)  - Virtual-Processor Identifiers (VPID)
(XEN)  - Virtual NMI
(XEN)  - MSR direct-access bitmap
(XEN)  - Unrestricted Guest
(XEN) HVM: ASIDs enabled
(XEN) VMX: Disabling executable EPT superpages due to CVE-2018-12207
(XEN) HVM: VMX enabled
(XEN) HVM: Hardware Assisted Paging (HAP) detected
(XEN) HVM: HAP page sizes, 4kB, 2MB
(XEN) Brought up 4 CPUs
(XEN) Scheduling granularity: cpu, 1 CPU per sched-resource
(XEN) Initializing Credit2 scheduler
(XEN) Dom0 has maximum 648 PIRQs
(XEN)  Xen  kernel: 64-bit, lsb
(XEN)  Dom0 kernel: 64-bit, PAE, lsb, paddr 0x1000000 -> 0x4a00000
(XEN) PHYSICAL MEMORY ARRANGEMENT:
(XEN)  Dom0 alloc.:   0000000208000000->0000000210000000 (1948531 pages 
to be allocated)
(XEN)  Init. ramdisk: 000000032c0B4000->000000021e5ffd12
(XEN) VIRTUAL MEMORY ARRANGEMENT:
(XEN)  Loaded kernel: ffffffff81000000->ffffffff84a00000
(XEN)  Phys-Mach map: 0000008000000000->0000008000f30778
(XEN)  Start info:    ffffffff84a00000->ffffffff84a004b8
(XEN)  Page tables:   ffffffff84a01000->ffffffff84a2a000
(XEN)  Boot stack:    ffffffff84a2a000->ffffffff84a2b000
(XEN)  TOTAL:         ffffffff80000000->ffffffff84c00000
(XEN)  ENTRY ADDRESS: ffffffff8306e1c0
(XEN) Dom0 has maximum 4 VCPUS
(XEN) Bogus DMIBAR 0xfed18001 on 0000:00:00.0
(XEN) Initial low memory virq threshold set at 0x4000 pages.
(XEN) Scrubbing Free RAM in background
(XEN) Std. Loglevel: Errors and warnings
(XEN) Guest Loglevel: Nothing (Rate-limited: Errors and warnings)
(XEN) ***************************************************
(XEN) Booted on L1TF-vulnerable hardware with SMT/Hyperthreading
(XEN) enabled.  Please assess your configuration and choose an
(XEN) explicit 'smt=<bool>' setting.  See XSA-273.
(XEN) ***************************************************
(XEN) Booted on MLPDS/MFBDS-vulnerable hardware with SMT/Hyperthreading
(XEN) enabled.  Mitigations will not be fully effective.  Please
(XEN) choose an explicit smt=<bool> setting.  See XSA-297
(XEN) ****************************************************
(XEN) 3... 2... 1...

-----------------------------

-Jamie