Re: [Qemu-devel] Can not relocate APIC registers address from 0xFEE00000 to self-defined physical addr

[Paolo Bonzini <pbonzini@redhat.com>]

On 10/07/19 17:41, Philippe Mathieu-Daudé wrote:
> 
> I wrote a Small OS (based on linux0.11) support SMP, and it can run
> well on bochs, Now i want to migrate it to Qemu, i found that when i
> use wrmsr command to relocate the APIC regsiters addr to a new
> physical address, it can not work, i can not initial APIC timer to
> trigger timer interrupt by the new physical addr just i relocate, but
> when use rdmsr to get APIC base addr has been changed to the new
> physical address, it's strange. In SMP env, if can not relocate APIC
> registers addr for each processor with  different addr, it will
> result in conflict. So, i want to know qemu4.0 whether support
> remaping APIC base address by wrmsr command? if support, please tell
> me how to remap APIC base addr for each processor.

Yes, this is not supported by QEMU.  However, you don't need to change
the base address, because each processor will only write to its own APIC
even if all of them use the same base address.

Paolo