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Re: [Qemu-devel] How does a system call work on QEMU?
From: |
Glauber Costa |
Subject: |
Re: [Qemu-devel] How does a system call work on QEMU? |
Date: |
Fri, 15 May 2009 01:49:14 -0300 |
On Thu, May 14, 2009 at 3:00 PM, grisu46 <address@hidden> wrote:
> Avi Kivity ha scritto:
>>
>> grisu46 wrote:
>>>>
>>>> No. Look at target-i386/translate.c, case 0x105 for syscall emulation.
>>>> Eventually it ends up calling helper_syscall().
>>>>
>>>
>>> Simplify?
>>> I am a newbie.
>>
>> Sorry, you're on your own. I can give you pointers but it's up to you to
>> follow them. If you're serious about understanding qemu you should be
>> prepared a lot of time reading the source code and processor documentation.
>>
> I would like to know how a virtualization program can perform a sensitive
> but not privileged operation. I learn about Xen and I like to understand (no
> deep details need) differences between Xen paravirtualization and QEMU
> emulator.
>
As the name suggests, qemu (in this case) is a processor _emulator_. You're not
doing any kind of sensitive operations on your host processor here.
You are emulating
a processor, an all state change happens in the emulated processor.
* qemu reads the instruction.
* qemu updates its internal state accordingly.
* qemu reads next instruction.
No big secret here.
--
Glauber Costa.
"Free as in Freedom"
http://glommer.net
"The less confident you are, the more serious you have to act."
- [Qemu-devel] How does a system call work on QEMU?, helicoterus-elih, 2009/05/13
- Re: [Qemu-devel] How does a system call work on QEMU?, helicoterus-elih, 2009/05/14
- Re: [Qemu-devel] How does a system call work on QEMU?, Paul Brook, 2009/05/14
- Re: [Qemu-devel] How does a system call work on QEMU?, Heli, 2009/05/14
- Re: [Qemu-devel] How does a system call work on QEMU?, Avi Kivity, 2009/05/14
- Re: [Qemu-devel] How does a system call work on QEMU?, grisu46, 2009/05/15
- Re: [Qemu-devel] How does a system call work on QEMU?, Avi Kivity, 2009/05/14
- Re: [Qemu-devel] How does a system call work on QEMU?, grisu46, 2009/05/15
- Re: [Qemu-devel] How does a system call work on QEMU?,
Glauber Costa <=
- Re: [Qemu-devel] How does a system call work on QEMU?, Heli, 2009/05/17
- Re: [Qemu-devel] How does a system call work on QEMU?, Avi Kivity, 2009/05/17
- Re: [Qemu-devel] How does a system call work on QEMU?, Fernando Carrijo, 2009/05/17
Re: [Qemu-devel] How does a system call work on QEMU?, Mulyadi Santosa, 2009/05/14
Re: [Qemu-devel] How does a system call work on QEMU?, helicoterus-elih, 2009/05/15