Re: [Qemu-devel] did the qemu can emulate the whole system with the processor that without support the "virtulization and kvm"?

["Alex Bennée" <alex.bennee@linaro.org>]

tugouxp <13824125580@163.com> writes:

> thank you.
>
> i just want to confirm one thing,  that is whether the qemu can emulate a whole operation system just by analysis instructions by instructions manually  without the support of KVM.
> so from the answer you give to me, it is feasible, right?

Yes - if you run qemu-system-$(ARCH) you are emulating a full machine
with hardware attached. It can either use TCG or a HW based acceleration
like KVM. HW based acceleration is only available on the same machine
type.

There is a third type - qemu-$(ARCH) which is often called linux-user
mode. Here the translation engine only translates instruction from guest
to the host and then maps system calls to the host system. This is isn't
emulating a whole system but allows you to run binaries from one
architecture on another.

>
>
>
> thanks very much!
>
>
>
>
>
>
>
>
>
> At 2018-12-21 17:01:02, "Alex Bennée" <alex.bennee@linaro.org> wrote:
>>
>>tugouxp <13824125580@163.com> writes:
>>
>>> Hi alex:
>>>     now my host machine did not have the "/dev/kvm" nodes and no chance to make it exists.
>>> so i want to know whether the "/dev/kvm" is  mandatory  for qemu to emulate the whole system.
>>> so i can make the emulation without the support of kvm mechanism.
>>
>>QEMU runs in two modes - full system emulation with TCG doesn't require
>>KVM although it is relatively slow. On systems where there guest
>>architecture is the same as the host architecture you can run with KMV
>>(or HAX/WHPX/HVF) accelerators at near native speeds.
>>
>>The reasons for not having a /dev/kvm can vary but you haven't said what
>>your host architecture is and what OS you are running so it's hard to
>>offer advice here.
>>
>>--
>>Alex Bennée


--
Alex Bennée