Re: [sisyphus] IQ: kernel-image-std-smp-2.6.24-alt0.3

[Led <ledest@gmail.com>]

В сообщении от Wednesday 27 February 2008 16:23:25 вы написали:
> On [Wed, 27.02.2008 16:14], Led wrote:
> > В сообщении от Wednesday 27 February 2008 16:12:55 вы написали:
> > > On [Wed, 27.02.2008 15:55], Led wrote:
> > > > Не знаю из-за этого или нет, но qemu-kvm в сизифе принудительно
> > > > собран gcc4.1, а не gcc3.4
> > >
> > > Этого делать нельзя.
> > >
> > > > Could someone please explain the issue with gcc4, please?  Or point
> > > > me to an existing explanation?
> > >
> > > The issue is that gcc4 optimizes better, but this breaks assumptions of
> > > QEmu.
> > >
> > > Example: The basic idea (simplified!) of QEmu is writing C functions
> > > which implement the instructions of the target CPU. Then, code to be
> > > emulated is translated by chaining the _compiled_ functions
> > > (corresponding to the target code) together, but _leaving_ out the
> > > return instruction at the end of the function (otherwise, the resulting
> > > code would return already after the first emulated instruction).
> > >
> > > Now, gcc4 can produce code with several return instructions (with no
> > > option to turn that of, as far as I understand). You cannot cut them
> > > out, and therefore you cannot chain the simple functions.
> > >
> > > There seem to be other issues, too, like not being able to correctly
> > > link the user emulation code, but I am not that sure about it.
> >
> > qemu-kvm ничего практически не эмулирует, а использует аппаратную
> > виртуализацию, поэтому он только для запуска x84_64 и x86_32
>
> Аппаратной виртуализации подлежат все инструкции или часть всё же
> эмулируется средствами qemu?

AFAIK все

-- 
Led