Hi, henanwxr,
At 17:59 +0100 on 26 May (1306432756), henanwxr wrote:> Hi, Tim. I have some questions.
Please post your questions on xen-devel instead of emailing people
directly. That way, if I don''t know the answer, someone else might;
and
if I do reply, the answer will be in the archives for other people to
find.
> when user create the virtual machine, then:
> 1. Which code execute firstly, hvmloaer or qemu-dm?I have traced the
> codes flow and found qemu-dm run before hvmloader,right?
Qemu-dm starts running before HVMloader, but after that they run at the
same time. HVMloader runs inside the virtual machine, and qemu-dm runs
in dom0.
> 2. And virtual bios code are both in hvmloader and qemu-dm, but I
> think it should be only one of virtual bios will be used to initialize
> the virutal device in qemu-dm.I find at the end of hvmloader it will
> jmp to 0xffff0, that is the bios entry,so I think the virtual bios in
> hvmloader will function and virtual bios in qemu-dm don''t execute.
Yes, exactly. If there is any BIOS code in qemu-dm, ignore it. Under
Xen, the BIOS that runs inside a virtual machine is the one in
HVMloader.
> But how qemu-dm ingore the execution of its virual bios inside?
I don''t know exactly how. Presumably the code in qemu-dm that would
load a BIOS into guest memory isn''t called in the xen case. Perhaps
you
could read the qemu code if you want to know the details.
Tim.
--
Tim Deegan <Tim.Deegan@citrix.com>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd. (Company #02937203, SL9 0BG)
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