Re: fast system calls

Re: fast system calls

[pallavi jk]

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Thanx a lot Jeremy!

In addition to removing the special case for 0x80 in
arch/x86/traps.c:do_set_trap_table(), will I also have to define an entry
point in xen/arch/x86/x86_32/entry.S as ENTRY(system_call)  ??

Could you please tell me other required modifications that I will have to
make?

-Pallavi

On Sat, Dec 27, 2008 at 12:33 PM, Jeremy Fitzhardinge <jeremy@goop.org>wrote:

> pallavi jk wrote:
>
>> I want to modify xen 3.3.0 so that control transfers to xen after system
>> calls. How can I disable fast system call handlers, so that int 0x80h
>> functions just like all other interrupts.
>>
>
> It should just be a matter of removing the special case for 0x80 in
> arch/x86/traps.c:do_set_trap_table().
>
>   J
>

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Re: fast system calls

[Jeremy Fitzhardinge]

pallavi jk wrote:
> Thanx a lot Jeremy!
>
> In addition to removing the special case for 0x80 in 
> arch/x86/traps.c:do_set_trap_table(), will I also have to define an 
> entry point in xen/arch/x86/x86_32/entry.S as ENTRY(system_call)  ??

No, I shouldn't think so.  Xen doesn't care what purpose the guest is 
using int 0x80 for; without the special case, it should Just Work.

> Could you please tell me other required modifications that I will have 
> to make?

I don't know off the top of my head.  There could be some other 
complication.

    J