#!/usr/bin/python3
'''
To make use of this script, you will need to run it as root and have installed
the Python portio package.

You need to have patched the portio operation in vmx.c and svm.c which can be
found at xen/arch/x86/hvm/{vmx,svm}/{vmx.c,svm.c} as shown below so that it
will run the deprivileged mode when we perform a particular port operation.
My series has the basic hook in there for patch 2 but this is commented
 out/removed in later patches as there was a functional change (you can
no longer just enter the mode, you need to supply an operation to jump to so
this will need to be updated to work with that).

This is in vmx_vmexit_handler and svm_vmexit_handler

Here is the svm part of this copied here for completeness:

             uint16_t port = (vmcb->exitinfo1 >> 16) & 0xFFFF;
             int bytes = ((vmcb->exitinfo1 >> 4) & 0x07);

             int dir = (vmcb->exitinfo1 & 1) ? IOREQ_READ : IOREQ_WRITE;
             /* DEBUG: Run only for a specific port */
             if(port == 0x1000)
             {
                 if( guest_cpu_user_regs()->eax == 0x1)
                 {
                     hvm_deprivileged_user_mode();
                 }
                 __update_guest_eip(regs, vmcb->exitinfo2 - vmcb->rip);
                 break;
             }

             if ( handle_pio(port, bytes, dir) )
                 __update_guest_eip(regs, vmcb->exitinfo2 - vmcb->rip);
         }

'''
import array

#Use for command line args
import sys
import pickle
import time

from portio import ioperm, iopl, outb

def prepare_portio(port):
    #Get access to all ports (needed on Linux pre 2.6.? kernel)
    if( iopl(3) != 0 ):
        print("ERROR: Elevating access to ports " + str(port) + "\n")
        return False

    #get access to port, only one port, and enable it
    if( ioperm(port, 1, 1) != 0 ):
        print("ERROR: Preparing port " + str(port) + "\n")
        return False

    return True

"""
Clean up after portio operations
"""
def release_portio(port):

    if( ioperm(port, 1, 0) != 0 ):
        print("ERROR: Releasing port " + str(port) + " \n")
        return False

    if( iopl(0) != 0 ):
        print("ERROR: Clearing access to ports " + str(port) + "\n")
        return False

    return True

'''
Needs root to run
'''
def send_data(port, data):
    outb(data, port)

def profile(outputTimes, numIterations, port, data):
    i = 0
    while (i < numIterations):
        before = time.time()
        send_data(port, data)
        after = time.time()

        timeDelta = after - before

        outputTimes.append( timeDelta)

        i = i + 1

def main():
    outputTimesWith = array.array("f")
    outputTimesWithout = array.array("f")
    portWith = 0x1000
    portWithout = 0x1000
    dataWith = 0x1
    dataWithout =0x2
    numIterations = 100000

    prepare_portio(portWith)

    #Profile the system
    #With the deprivileged op
    profile(outputTimesWith, numIterations, portWith, dataWith);
    release_portio(portWith)

    #Without the deprivileged op
    prepare_portio(portWithout)
    profile(outputTimesWithout, numIterations, portWithout, dataWithout);
    release_portio(portWithout)

    data =[outputTimesWith, outputTimesWithout]

    outputFile = open("data", "wb")

    pickle.dump(data, outputFile)

    outputFile.close()
    return

if __name__ == '__main__':
    main()