> I take it self-modifying kernel code would have serious issues.
Seems likely :-) With hardware support, making things like this work should
be *much* easier.
> I seem to recall my attempts to run v2OS (which uses a self-modifying
> assembly code boot sequence) inside VMWare crashing badly cir
> VMware handles kernel code. You are right that x86 code can't be 100%
> virtualized
> (even at the userland level) but VMware uses a lot of nasty disgusting tricks
> in order to work around them. (For example, playing with shadow pagetables
> so that a page of modified code is run but if the cod
On Wed, Sep 14, 2005 at 10:18:24AM -0700, John R. Hogerhuis wrote:
> Why disgusting?
>
> Perhaps you meant disgusting because the Intel architecture forces a
> virtualizer to handle a bunch of corner cases like this.
>
That is exactly what I mean.
> -- John.
>
--
Infinite complexity begets
On Wed, Sep 14, 2005 at 01:46:58PM -0500, Anthony Liguori wrote:
> You can't readahead beyond a basic block. Taking a trap for each basic
> block and translating the block is what QEMU does.
>
No, QEMU translates everything from guest machine code into its internal codes.
I'm talking about usi
Jim C. Brown wrote:
On Tue, Sep 13, 2005 at 11:27:39PM -0500, Anthony Liguori wrote:
I reckon kqemu has this same problem... Technically, even in ring 3, if
you run natively, you violate the Popek/Goldberg requirements because of
cpuid. It's just not possible to trap it but it shouldn't ma
> > There are a couple of interesting paravirtualization techniques too.
> > There's the Xen approach (really fast, but very invasive), the L4ka
> > afterburning (theoritically close to as fast, but less invasive), and
> > then of course the extremes like UML.
>
> Not familar with L4ka. I don't bel
Two side footnotes to your comprehensive explanation:
1) with the SKAS host kernel patch you don't have to ptrace the "guest"
processes and performance (and security) is improved quite a bit, I
understand.
2) UML is currently being ported to run in ring 0. Why? Not for running on
native hard
On Wed, 2005-09-14 at 09:37 -0400, Jim C. Brown wrote:
> VMware handles kernel code. You are right that x86 code can't be 100%
> virtualized
> (even at the userland level) but VMware uses a lot of nasty disgusting tricks
> in order to work around them. (For example, playing with shadow pagetables
On Wed, 14 Sep 2005, Jim C. Brown wrote:
Not familar with L4ka. I don't believe that UML does virtualization, it simply
runs linux code 'as is' but intercepts calls to the kernel.
UML does not do hardware virtualization. UML is a special architecture for
the Linux kernel allowing Linux to run
On Tue, Sep 13, 2005 at 11:27:39PM -0500, Anthony Liguori wrote:
> I reckon kqemu has this same problem... Technically, even in ring 3, if
> you run natively, you violate the Popek/Goldberg requirements because of
> cpuid. It's just not possible to trap it but it shouldn't matter for
> most sof
On Tue, Sep 13, 2005 at 09:48:01PM -0500, Anthony Liguori wrote:
> Jim C. Brown wrote:
>
> The x86 cannot be "virtualized" in the Popek/Goldberg sense, so there's
> a couple of fast emulation techniques that are possible. Other than a
> hand coded dynamic translator, I reckon qemu + kqemu is ab
Well, VMware guests can recognise that they're in a VM because the
software contains a backdoor INT function, mainly used by VMware Tools
for things like Shared Folders and host-controlled mouse cursors
insides guests. I don't quite remember what the function was for
VMware's backdoor, but you can
Mark Williamson wrote:
No, I got the impression that Fabrice was taking about virtualization the
way VMware, old plex86, and vmbear (new FOSS x86 virtualizer in the
works) do it.
The x86 cannot be "virtualized" in the Popek/Goldberg sense, so there's
a couple of fast emulation techniques
> >No, I got the impression that Fabrice was taking about virtualization the
> > way VMware, old plex86, and vmbear (new FOSS x86 virtualizer in the
> > works) do it.
>
> The x86 cannot be "virtualized" in the Popek/Goldberg sense, so there's
> a couple of fast emulation techniques that are possibl
Jim C. Brown wrote:
On Tue, Sep 13, 2005 at 09:58:11AM -0500, Anthony Liguori wrote:
Jim C. Brown wrote:
Fabrice had said that he > >wants
kqemu to be able to do total virtualization (both kernel and userland > >bits);
basically all the translation code of qemu would be left unused bu
> No, I got the impression that Fabrice was taking about virtualization the
> way VMware, old plex86, and vmbear (new FOSS x86 virtualizer in the works)
> do it.
>
> So it'll work w/o needing a 64bit chip.
I hadn't seen vmbear, looks interesting... Full virtualisation on vanilla x86
would be rea
On Tue, Sep 13, 2005 at 09:58:11AM -0500, Anthony Liguori wrote:
> Jim C. Brown wrote:
>
> >Fabrice had said that he > >wants
> >kqemu to be able to do total virtualization (both kernel and userland >
> >>bits);
> >basically all the translation code of qemu would be left unused but the
> >hardwa
On 9/13/05, Adrian Smarzewski <[EMAIL PROTECTED]> wrote:
> Alexandre Leclerc wrote:
> > I'm new to qemu and my question is simple and is probably due to my
> > ignorance. If I compare qemu and vmware, there is a great deal of
> > emulation speed differences.
>
> Did you try kqemu or qvm86?
Yes, w
Jim C. Brown wrote:
- If no, is it possible that one day qemu reaches the speed of vmware?
qemu itself? Nope.
kqemu/qvm86 don't have this limitation though. Fabrice had said that he wants
kqemu to be able to do total virtualization (both kernel and userland bits);
basically all the tran
On Tue, Sep 13, 2005 at 08:36:29AM -0400, Alexandre Leclerc wrote:
> Hi all,
>
> I'm new to qemu and my question is simple and is probably due to my
> ignorance. If I compare qemu and vmware, there is a great deal of
> emulation speed differences.
>
> - Is it because of what qemu is? (i.e. it is
Alexandre Leclerc wrote:
I'm new to qemu and my question is simple and is probably due to my
ignorance. If I compare qemu and vmware, there is a great deal of
emulation speed differences.
Did you try kqemu or qvm86?
--
Pozdrowienia,
Adrian Smarzewski
_
Hi all,
I'm new to qemu and my question is simple and is probably due to my
ignorance. If I compare qemu and vmware, there is a great deal of
emulation speed differences.
- Is it because of what qemu is? (i.e. it is a full emulator of many
platforms, etc. Meaning that vmware is probably only spec
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