Re: [Xen-users] intercept and capture fast system call of linux

[Ian Campbell <ian.campbell@xxxxxxxxxx>]

On Fri, 2014-02-28 at 12:50 +0800, éèä wrote:
> hi,
> I want to intercept and capture fast  system call of linux. 
> (1)I set GUEST_SYSENTER_EIP to   0xDDDDD0AE in vmx_vmexit_handler, and
> save the real value.

Are you taking the chance that 0xddddd0ae is unmapped within the p2m? Is
there not an explicit trap for syscalls in the VMCS?

> (2)When a fast syscall come,  I will caputue it in sh_page_fault.
> (3) Then I set the real GUEST_SYSENTER_EIP(c0103ef0,
> ia32_sysenter_target) to GUEST_RIP.

Are you sure that setting GUEST_RIP is sufficient to cause the guest to
switch to that when you reenter? Is there nothing else you need to
change/update in order to simulate the affect of a syscall from the
guest PoV?

You might find it helpful to publish your actual code so people can see
what you've actually done..

You might also want to post to the -devel list instead.

Ian.



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