Re: [PATCH v2 16/17] kvm: x86: Rework identity map and TSS setup for larger BIOS sizes

Jan Kiszka
2011-01-03T17:19:26Z

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Am 03.01.2011 17:59, Avi Kivity wrote:
> On 01/03/2011 06:52 PM, Jan Kiszka wrote:
>> Am 03.01.2011 17:06, Avi Kivity wrote:
>> > On 01/03/2011 10:33 AM, Jan Kiszka wrote:
>> >> From: Jan Kiszka<jan.kiszka@siemens.com>
>> >>
>> >> First of all, we only need this EPT identity and TSS reservation on
>> >> Intel CPUs.
>> >
>> > kvm-amd will ignore it just fine. I'd like to keep arch differences
>> > away from userspace.
>>
>> And I would prefer to avoid needlessly cluttering the physical guest
>> address space where not needed. Long term, we could even give user space
>> a hint (unless it can test it directly) that this workaround is no
>> longer needed as the host Intel CPU supports true real mode.
>
> Having different physical address spaces based on the host cpu is bad,
> even disregarding live migration. If there's a real need, we can do it
> as an option. I don't see such a need though.

I see, migration is a killer argument.

Jan

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