Hi, After fixing the xhci crash, I hit another issue - booting with 236MB initrd doesn't work, I get: (XEN) [ 3.151856] *** Building a PVH Dom0 *** ... (XEN) [ 3.593940] Unable to allocate memory with order 0! (XEN) [ 3.597110] Failed to setup Dom0 physical memory map (XEN) [ 3.599884] (XEN) [ 3.602482] **************************************** (XEN) [ 3.605272] Panic on CPU 0: (XEN) [ 3.607928] Could not construct d0 (XEN) [ 3.610692] **************************************** (XEN) [ 3.613463] (XEN) [ 3.616035] Reboot in five seconds... (XEN) [ 8.626565] Resetting with ACPI MEMORY or I/O RESET_REG. Full console log: https://gist.github.com/marmarek/c9dbc87bf07b76f2899781755762f565 If I skip initrd, then it boots just fine (but dom0 is not happy about that). 164MB initrd failed too, but 13MB started ok. Just in case, I tried skipping XHCI console, but it didn't change anything. Host has 16GB of memory, and there is no dom0_mem= parameter. Xen is started from GRUB, using MB2+EFI. When it works (12MB initrd), I get the following info: (XEN) [ 4.123843] Dom0 memory allocation stats: (XEN) [ 4.126636] order 0 allocations: 4 (XEN) [ 4.129278] order 1 allocations: 3 (XEN) [ 4.132027] order 2 allocations: 4 (XEN) [ 4.134776] order 3 allocations: 3 (XEN) [ 4.137527] order 4 allocations: 3 (XEN) [ 4.140252] order 5 allocations: 3 (XEN) [ 4.142966] order 7 allocations: 2 (XEN) [ 4.145663] order 8 allocations: 3 (XEN) [ 4.148358] order 9 allocations: 3 (XEN) [ 4.151035] order 10 allocations: 4 (XEN) [ 4.153709] order 11 allocations: 7 (XEN) [ 4.156277] order 12 allocations: 9 (XEN) [ 4.158940] order 13 allocations: 6 (XEN) [ 4.161604] order 14 allocations: 6 (XEN) [ 4.164251] order 15 allocations: 7 (XEN) [ 4.166892] order 16 allocations: 6 (XEN) [ 4.169521] order 17 allocations: 4 (XEN) [ 4.172048] order 18 allocations: 10 (XEN) [ 4.994309] ELF: phdr: paddr=0x200000 memsz=0x1ff3928 (XEN) [ 4.997011] ELF: phdr: paddr=0x2200000 memsz=0x1c00000 (XEN) [ 4.999686] ELF: memory: 0x200000 -> 0x3e00000 (XEN) [ 5.002404] ELF: note: PHYS32_RELOC align: 0x200000 min: 0x200000 max: 0x3fffffff (XEN) [ 5.005451] ELF: note: PHYS32_ENTRY = 0x16a2ca0 (XEN) [ 5.008519] ELF: note: GUEST_OS = "linux" (XEN) [ 5.011562] ELF: note: GUEST_VERSION = "2.6" (XEN) [ 5.014634] ELF: note: XEN_VERSION = "xen-3.0" (XEN) [ 5.017712] ELF: note: VIRT_BASE = 0xffffffff80000000 (XEN) [ 5.020795] ELF: note: INIT_P2M = 0x8000000000 (XEN) [ 5.023856] ELF: note: ENTRY = 0xffffffff82d3c160 (XEN) [ 5.026924] ELF: note: FEATURES = "!writable_page_tables" (XEN) [ 5.029976] ELF: note: PAE_MODE = "yes" (XEN) [ 5.032882] ELF: note: L1_MFN_VALID (XEN) [ 5.035516] ELF: note: MOD_START_PFN = 0x1 (XEN) [ 5.038442] ELF: note: PADDR_OFFSET = 0 (XEN) [ 5.041250] ELF: note: SUPPORTED_FEATURES = 0x8801 (XEN) [ 5.044169] ELF: note: LOADER = "generic" (XEN) [ 5.047048] ELF: note: SUSPEND_CANCEL = 0x1 (XEN) [ 5.049931] ELF: Found PVH image (XEN) [ 5.052712] ELF: addresses: (XEN) [ 5.055090] virt_base = 0x0 (XEN) [ 5.057552] elf_paddr_offset = 0x0 (XEN) [ 5.060007] virt_offset = 0x0 (XEN) [ 5.062476] virt_kstart = 0x200000 (XEN) [ 5.064924] virt_kend = 0x3e00000 (XEN) [ 5.067380] virt_entry = 0x16a2ca0 (XEN) [ 5.069841] p2m_base = 0x8000000000 (XEN) [ 5.072319] ELF: phdr 0 at 0x200000 -> 0x21f3928 (XEN) [ 5.080076] ELF: phdr 1 at 0x2200000 -> 0x3e00000 (XEN) [ 5.090182] Dom0 memory map: (XEN) [ 5.092531] [0000000000000000, 000000000009efff] (usable) (XEN) [ 5.095086] [000000000009f000, 00000000000fffff] (reserved) (XEN) [ 5.097625] [0000000000100000, 000000005471afff] (usable) (XEN) [ 5.100156] [000000005471b000, 000000005475bfff] (reserved) (XEN) [ 5.102704] [000000005475c000, 0000000063c2dfff] (usable) (XEN) [ 5.105259] [0000000063c2e000, 000000006d17afff] (reserved) (XEN) [ 5.107853] [000000006d17b000, 000000006d22bfff] (ACPI data) (XEN) [ 5.110459] [000000006d22c000, 000000006d2ebfff] (ACPI NVS) (XEN) [ 5.113082] [000000006d2ec000, 000000006fffefff] (reserved) (XEN) [ 5.115726] [000000006ffff000, 000000006ffffdcb] (usable) (XEN) [ 5.118388] [000000006ffffdcc, 000000006ffffe97] (ACPI data) (XEN) [ 5.121080] [0000000070000000, 00000000807fffff] (reserved) (XEN) [ 5.123776] [00000000c0000000, 00000000cfffffff] (reserved) (XEN) [ 5.126498] [00000000fe000000, 00000000fe010fff] (reserved) (XEN) [ 5.129244] [00000000fec00000, 00000000fec00fff] (reserved) (XEN) [ 5.132001] [00000000fed00000, 00000000fed00fff] (reserved) (XEN) [ 5.134797] [00000000fed20000, 00000000fed7ffff] (reserved) (XEN) [ 5.137619] [00000000fee00000, 00000000fee00fff] (reserved) (XEN) [ 5.140436] [00000000ff000000, 00000001023fffff] (reserved) (XEN) [ 5.143271] [0000000102400000, 0000000468b34fff] (usable) (XEN) [ 5.146131] [0000000468b35000, 000000047f7fffff] (unusable) (XEN) [ 5.149015] Initial low memory virq threshold set at 0x4000 pages. (XEN) [ 5.151852] Scrubbing Free RAM in background (XEN) [ 5.154667] Std. Loglevel: All (XEN) [ 5.157465] Guest Loglevel: All (XEN) [ 5.160250] Xen is relinquishing VGA console. (XEN) [ 5.166762] *** Serial input to DOM0 (type 'CTRL-a' three times to switch input) (XEN) [ 5.167550] Re-running stub recovery selftests... (XEN) [ 5.167692] Fixup #UD[0000]: ffff82d07fffe044 [ffff82d07fffe044] -> ffff82d0403b8753 (XEN) [ 5.167914] Fixup #GP[0000]: ffff82d07fffe045 [ffff82d07fffe045] -> ffff82d0403b8753 (XEN) [ 5.168139] Fixup #SS[0000]: ffff82d07fffe044 [ffff82d07fffe044] -> ffff82d0403b8753 (XEN) [ 5.168359] Fixup #BP[0000]: ffff82d07fffe045 [ffff82d07fffe045] -> ffff82d0403b8753 (XEN) [ 5.168662] Freed 720kB init memory (XEN) [ 6.884758] d0v0: upcall vector f3 Interestingly, this appear to have worked on Xen 4.19.3. -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab