On 04/06/2019 13:43, Jan Beulich wrote:
> Split out this mostly arch-independent code into a common-code helper
> function. (This does away with Arm's arch_init_memory() altogether.)
>
> On x86 this needs to happen before acpi_boot_init(): Commit 9fa94e1058
> ("x86/ACPI: also parse AMD IOMMU tables early") only appeared to work
> fine - it's really broken, and doesn't crash (on non-EFI AMD systems)
> only because of there being a mapping of linear address 0 during early
> boot. On EFI there is:
>
> Early fatal page fault at e008:ffff82d08024d58e (cr2=0000000000000220,
> ec=0000)
> ----[ Xen-4.13-unstable x86_64 debug=y Not tainted ]----
> CPU: 0
> RIP: e008:[<ffff82d08024d58e>] pci.c#_pci_hide_device+0x17/0x3a
> RFLAGS: 0000000000010046 CONTEXT: hypervisor
> rax: 0000000000000000 rbx: 0000000000006000 rcx: 0000000000000000
> rdx: ffff83104f2ee9b0 rsi: ffff82e0209e5d48 rdi: ffff83104f2ee9a0
> rbp: ffff82d08081fce0 rsp: ffff82d08081fcb8 r8: 0000000000000000
> r9: 8000000000000000 r10: 0180000000000000 r11: 7fffffffffffffff
> r12: ffff83104f2ee9a0 r13: 0000000000000002 r14: ffff83104f2ee4b0
> r15: 0000000000000064 cr0: 0000000080050033 cr4: 00000000000000a0
> cr3: 000000009f614000 cr2: 0000000000000220
> fsb: 0000000000000000 gsb: 0000000000000000 gss: 0000000000000000
> ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0000 cs: e008
> Xen code around <ffff82d08024d58e> (pci.c#_pci_hide_device+0x17/0x3a):
> 48 89 47 38 48 8d 57 10 <48> 8b 88 20 02 00 00 48 89 51 08 48 89 4f 10 48
> Xen stack trace from rsp=ffff82d08081fcb8:
> [...]
> Xen call trace:
> [<ffff82d08024d58e>] pci.c#_pci_hide_device+0x17/0x3a
> [ [< >] pci_ro_device+...]
What is this in the stack trace?
> [<ffff82d080617fe1>] amd_iommu_detect_one_acpi+0x161/0x249
> [<ffff82d0806186ac>] iommu_acpi.c#detect_iommu_acpi+0xb5/0xe7
> [<ffff82d08061cde0>] acpi_table_parse+0x61/0x90
> [<ffff82d080619e7d>] amd_iommu_detect_acpi+0x17/0x19
> [<ffff82d08061790b>] acpi_ivrs_init+0x20/0x5b
> [<ffff82d08062e838>] acpi_boot_init+0x301/0x30f
> [<ffff82d080628b10>] __start_xen+0x1daf/0x28a2
>
> Pagetable walk from 0000000000000220:
> L4[0x000] = 000000009f44f063 ffffffffffffffff
> L3[0x000] = 000000009f44b063 ffffffffffffffff
> L2[0x000] = 0000000000000000 ffffffffffffffff
>
> ****************************************
> Panic on CPU 0:
> FATAL TRAP: vector = 14 (page fault)
> [error_code=0000] , IN INTERRUPT CONTEXT
> ****************************************
>
> Of course the bug would nevertheless have lead to post-boot crashes as
> soon as the list would actually get traversed.
>
> Take the opportunity and
> - convert BUG_ON()s being moved to panic(),
> - add __read_mostly annotations to the dom_* definitions.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
Sorry for not noticing this before, but s/special/system/ to match up
with the existing terminology in is_system_domain()
> --- a/xen/include/xen/mm.h
> +++ b/xen/include/xen/mm.h
> @@ -642,6 +642,9 @@ static inline void filtered_flush_tlb_ma
> }
> }
>
> +/* Private domain structs for DOMID_XEN, DOMID_IO, etc. */
> +extern struct domain *dom_xen, *dom_io, *dom_cow;
> +
Any chance you can move these higher up, to before the include of
<asm/mm.h>, or you're going to break Julien's M2P series.
With at least the name adjusted, Reviewed-by: Andrew Cooper
<andrew.coop...@citrix.com>
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