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SubjectRe: [PATCH] ACPI: x86: Call acpi_boot_table_init() after acpi_table_upgrade()
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On 13.04.21 19:53, Rafael J. Wysocki wrote:
> On Tue, Apr 13, 2021 at 7:43 PM David Hildenbrand <david@redhat.com> wrote:
>>
>> On 13.04.21 16:01, Rafael J. Wysocki wrote:
>>> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>>
>>> Commit 1a1c130ab757 ("ACPI: tables: x86: Reserve memory occupied by
>>> ACPI tables") attempted to address an issue with reserving the memory
>>> occupied by ACPI tables, but it broke the initrd-based table override
>>> mechanism relied on by multiple users.
>>>
>>> To restore the initrd-based ACPI table override functionality, move
>>> the acpi_boot_table_init() invocation in setup_arch() on x86 after
>>> the acpi_table_upgrade() one.
>>>
>>> Fixes: 1a1c130ab757 ("ACPI: tables: x86: Reserve memory occupied by ACPI tables")
>>> Reported-by: Hans de Goede <hdegoede@redhat.com>
>>> Tested-by: Hans de Goede <hdegoede@redhat.com>
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>>> ---
>>>
>>> George, can you please check if this reintroduces the issue addressed by
>>> the above commit for you?
>>>
>>> ---
>>> arch/x86/kernel/setup.c | 5 ++---
>>> 1 file changed, 2 insertions(+), 3 deletions(-)
>>>
>>> Index: linux-pm/arch/x86/kernel/setup.c
>>> ===================================================================
>>> --- linux-pm.orig/arch/x86/kernel/setup.c
>>> +++ linux-pm/arch/x86/kernel/setup.c
>>> @@ -1045,9 +1045,6 @@ void __init setup_arch(char **cmdline_p)
>>>
>>> cleanup_highmap();
>>>
>>> - /* Look for ACPI tables and reserve memory occupied by them. */
>>> - acpi_boot_table_init();
>>> -
>>> memblock_set_current_limit(ISA_END_ADDRESS);
>>> e820__memblock_setup();
>>>
>>> @@ -1132,6 +1129,8 @@ void __init setup_arch(char **cmdline_p)
>>> reserve_initrd();
>>>
>>> acpi_table_upgrade();
>>> + /* Look for ACPI tables and reserve memory occupied by them. */
>>> + acpi_boot_table_init();
>>>
>>> vsmp_init();
>>
>> This is fairly late; especially, it's after actual allocations -- see
>> e820__memblock_alloc_reserved_mpc_new().
>>
>> Can't the table upgrade mechanism fix up when adjusting something?
>
> Not at this point of the cycle I'm afraid.
>
>> Some details on what actually breaks would be helpful.
>
> Generally speaking, the table overrides that come from the initrd are
> not taken into account if acpi_boot_table_init() runs before
> acpi_table_upgrade() and the latter cannot run before
> reserve_initrd().

I see. (looking at Documentation/acpi/initrd_table_override.txt I
understand what acpi table overrides are for :) )

>
> Honestly, I'm not sure how much effort it would take to untangle this ATM.

Also true; ideally, we wouldn't have any allocations (find+reserve)
before ordinary reservations are done.

However, I have no idea if we can move
e820__memblock_alloc_reserved_mpc_new() and reserve_real_mode() around
easily. Also, reserve_initrd()->relocate_initrd() does allocations.

This is a mess.

--
Thanks,

David / dhildenb

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