Re: [PATCH v1] x86/apic: Fix kernel panic when "intremap=off" and "x2apic_phys" are set

[Borislav Petkov]

On Sat, Jun 17, 2023 at 02:52:36AM +0530, Dheeraj Kumar Srivastava wrote:
> x2APIC mode requires "Interrupt Remapping" to be enabled and the
> "physical x2apic" driver can be used only when x2APIC mode is enabled.
> However when "intremap=off" and "x2apic_phys" kernel command line
> parameters are passed, "physical x2apic" driver is being used even when
> x2APIC mode is disabled ("intremap=off" disables x2APIC mode).
> This results in the below kernel panic:
> 
>   unchecked MSR access error: RDMSR from 0x80f at rIP: 0xffffffff87eab4ec

Not a kernel panic - that's a warning about accessing a non-existent
MSR.

Can you send full dmesg? Privately is fine too.

How exactly do you trigger this? What hw?

Thx.

-- 
Regards/Gruss,
    Boris.

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