Messages in this thread | | | Subject | Re: [tip:x86/urgent] x86/apic: Fix signedness bug in APIC ID validity checks | From | Dou Liyang <> | Date | Wed, 11 Apr 2018 15:01:54 +0800 |
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Hi Thomas,
At 04/10/2018 10:51 PM, tip-bot for Li RongQing wrote: [...]
> x86/apic: Fix signedness bug in APIC ID validity checks > > The APIC ID as parsed from ACPI MADT is validity checked with the > apic->apic_id_valid() callback, which depends on the selected APIC type. > > For non X2APIC types APIC IDs >= 0xFF are invalid, but values > 0x7FFFFFFF
Today when I am reading "Intel® 64 Architecture x2APIC Specification", I find that below in chapter 2.4.1:
The APIC ID value of FFFF_FFFFH and the highest value corresponding to the imple-mented bit-width of the local APIC ID register in the system are reserved and cannot be assigned to any logical processor.
Seems, FFFF_FFFFH is also invalid for X2APIC types, Shall we also do the validity check for X2APIC ID?
acpi_parse_x2apic() ... /* Ignore invalid ID */ if (apic_id == 0xffffffff) return 0; ...
Thanks, dou
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