RE: [Xen-devel] Declaring new Xen Hypercall

[Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>]

If I recall correctly, the assembly language code in Xen
that is executed first when a hypercall enters into Xen
checks if the hypercall is done from userpace and disallows
the call (returning -1) if it is.

> -----Original Message-----
> From: Nimgaonkar, Satyajeet [mailto:SatyajeetNimgaonkar@xxxxxxxxxx]
> Sent: Tuesday, September 28, 2010 2:07 PM
> To: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: [Xen-devel] Declaring new Xen Hypercall
> 
> Hi All,
>          I am currently working on declaring a new hypercall in Xen.
> For this i have declared my hypercall in xen.h -
> #define __HYPERVISOR_jeet1                56
> 
> Then I modified the xcom_privcmd.c to accomodate my hypercall -
>         case __HYPERVISOR_jeet1:
>                 printk("Successfull Hypercall made to
> __HYPERVISOR_jeet1");
> 
> And then I am calling this Hypercall through an user level program-
> 
> #include </home/satyajeet/Important_Softwares/xen-
> 3.4.3/tools/libxc/xc_private.h>
> #include <xenctrl.h>
> #include <stdio.h>
> 
> int main(){
> 
>        printf("Attempt to invoke the hypercall: __HYPERVISOR_jeet1\n");
>        int handle, rc;
> 
>          /* Acquire Hypervisor Interface Handle.
>             This handle goes as the first argument for the function
> do_xen_hypercall()
>          */
> 
>        handle = xc_interface_open();
>        printf ("Acquired handle to Xen Hypervisor:%d\n",handle);
> 
>        /* Hypercall definitions */
> 
>        DECLARE_HYPERCALL;
>        hypercall.op     = __HYPERVISOR_jeet1;
>        rc = do_xen_hypercall(handle, &hypercall);
>        printf ("Hypercall Details: %d\n", rc);
> 
>        xc_interface_close(handle);
> 
>        return 0;
> 
> }
> 
> The program compiles properly but gives me -1 error for rc. Can anyone
> please tell me what I am doing wrong here. Also please tell me where
> should I view the output of printk in xen.
> 
> Thanks in advance.
> 
> Regards,
> Satyajeet Nimgaonkar
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel