Re: [Xen-devel] Re: X86_emulate to be moved into qemu...

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 18 May 2006, at 10:33, Petersson, Mats wrote:

> > Yes, you could walk pagetables. But equally you can pass in
> > your translated CR2 value --- i.e., pass in a pseudophysical
> > address. That address will then be passed to the special
> > read/write hook functions, so you avoid needing to do the
> > translation inside those.
> Hmm, yes. But we also want CS:rIP translated, which isn't too bad. And
> for movs we have both the source and destination to take into account.
> ES:rDI isn't bad, but xS:rSI isn't as trivial, since we'd have to scan
> for segment overrides in that case - and now we're starting to look 
> like
> a bunch of decoding code in two places again... :-( [Admittedly not
> quite as much]
The code should be passed in a buffer. This will be needed for 
interfacing with VMX anyway, since it places the instruction in a handy 
on-chip buffer for convenient readout. That gets rid of any need for 
CS:RIP decoding.
Yes, we will need translation in a few places for dual-memory-operand 
instructions (MOVS, stack instructions, etc). So we will need to walk 
pagetables. It's just that the *common* case will be to need no walk. 
The segment override is no problem -- it's already implemented.
 -- Keir


> > What header files are those? It builds in tools/test/ without
> > so many header files.
> 'hg status' says:
I'll fix that.

 -- Keir

> M ioemu/target-i386-dm/Makefile
> M ioemu/target-i386-dm/helper2.c
> ? ioemu/target-i386-dm/x86_emulate.c
> ? libxc/asm-x86/bitops.h
> ? libxc/asm-x86/cache.h
> ? libxc/asm-x86/config.h
> ? libxc/asm-x86/desc.h
> ? libxc/asm-x86/mm.h
> ? libxc/asm-x86/page.h
> ? libxc/asm-x86/processor.h
> ? libxc/asm-x86/regs.h
> ? libxc/asm-x86/rwlock.h
> ? libxc/asm-x86/spinlock.h
> ? libxc/asm-x86/string.h
> ? libxc/asm-x86/system.h
> ? libxc/asm-x86/types.h
> ? libxc/asm-x86/uaccess.h
> ? libxc/asm-x86/x86_emulate.h
> ? libxc/public/arch-x86_32.h
> ? libxc/public/arch-x86_64.h
> ? libxc/public/xen-compat.h
> ? libxc/public/xen.h
>
> --
> Mats
> >   -- Keir
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel

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