(sorry for top posting)
Because the emulation quality is indeed a bit better with the per-CPU address
spaces; you could move each APIC's base address independent of the others.
However, this is not a feature that is actually used by anything in practice,
so I doubt anyone cares about TCG implementing it correctly.
Paolo
-----Original Message-----
From: Peter Maydell [peter.mayd...@linaro.org]
Received: lunedì, 24 ago 2015, 16:57
To: Paolo Bonzini [pbonz...@redhat.com]
CC: Eduardo Habkost [ehabk...@redhat.com]; Zhu Guihua
[zhugh.f...@cn.fujitsu.com]; ChenFan [chen.fan.f...@cn.fujitsu.com]; Igor
Mammedov [imamm...@redhat.com]; izumi.t...@jp.fujitsu.com, QEMU Developers
[qemu-devel@nongnu.org]; Andreas Färber [afaer...@suse.de]
Subject: Re: [Qemu-devel] [RESEND PATCH v9 1/4] apic: map APIC's MMIO region at
each CPU's address space
On 24 August 2015 at 01:55, Paolo Bonzini <pbonz...@redhat.com> wrote:
>
>
> On 21/08/2015 15:54, Eduardo Habkost wrote:
>> > + if (tcg_enabled()) {
>> > + memory_region_add_subregion_overlap(cpu->cpu_as_root,
>> > + apic->apicbase &
>> > + MSR_IA32_APICBASE_BASE,
>> > + &apic->io_memory,
>> > + 0x1000);
>>
>> Why exactly is this necessary? If this is necessary, why don't we need
>> to do this for non-TCG accelerators?
>
> At least KVM and qtest do not support per-CPU address spaces.
Right, but given this restriction why can't we also do whatever
we need to work without the per-CPU address spaces with TCG?
thanks
-- PMM
