From mboxrd@z Thu Jan  1 00:00:00 1970
From: leilei175 <leilei175@gmail.com>
Subject: Re: how can I find code of hypercall?
Date: Wed, 11 Mar 2009 20:37:15 +0800
Message-ID: <49B7B07B.60302@gmail.com>
References: <C5DD423F.4C68%keir.fraser@eu.citrix.com>
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To: Keir Fraser <keir.fraser@eu.citrix.com>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>, "Jayaraman,
	Bhaskar" <Bhaskar.Jayaraman@lsi.com>
List-Id: xen-devel@lists.xenproject.org

Hi, keir and Jayaraman,
Thanks for your explanation

Keir Fraser wrote:
> On 11/03/2009 10:08, "Jayaraman, Bhaskar" <Bhaskar.Jayaraman@lsi.com> wrote:
>
>   
>> I've done this on an HVM. For Intel, you can go to platform-pci and dump the
>> hypercall page on the console 4 bytes at a time. Each 4 byte value on the
>> hypercall page constitutes an Intel x86 instruction, and you should find
>> something like this: -
>> 0xc1010f00 
>> 0xccccccc3 
>>     
>
> You know x86 instructions are not fixed-length, right? Actually the
> instruction sequence is:
>  0xb8 <imm32>   : mov imm32,%eax (5-byte instruction)
>  0x0f 0x01 0xc1 : vmcall (3-byte instruction)
>  0xc3           : ret (1-byte instruction)
>
> See xen/arch/x86/hvm/vmx/vmx.c:vmx_init_hypercall_page().
>
>  -- Keir
>
>
>
>