#!/bin/bash
sed -i '/\[SVM_EXIT_VMGEXIT\]            = sev_handle_vmgexit,/a\    [SVM_EXIT_RDTSC]            = handle_rdtsc_interception,' arch/x86/kvm/svm/svm.c
sed -i '/    svm_set_intercept(svm, INTERCEPT_RSM);/a\    svm_set_intercept(svm, INTERCEPT_RDTSC);' arch/x86/kvm/svm/svm.c
sed -i '/static int (\*const svm_exit_handlers\[\])(struct kvm/e cat << '\''EOF'\''
static u32 print_once = 1;

static int handle_rdtsc_interception(struct kvm_vcpu *vcpu)
{
    static u64 rdtsc_fake = 0;
    static u64 rdtsc_prev = 0;
    u64 rdtsc_real = rdtsc();

    if(print_once)
    {
            printk("[handle_rdtsc] fake rdtsc svm function is working\n");
            print_once = 0;
            rdtsc_fake = rdtsc_real;
    }

    if(rdtsc_prev != 0)
    {
            if(rdtsc_real > rdtsc_prev)
            {
                    u64 diff = rdtsc_real - rdtsc_prev;
                    u64 fake_diff =  diff / 20; // if you have 3.2Ghz on your vm, change 20 to 16
                    rdtsc_fake += fake_diff;
            }
    }
    if(rdtsc_fake > rdtsc_real)
    {
            rdtsc_fake = rdtsc_real;
    }
    rdtsc_prev = rdtsc_real;

    vcpu->arch.regs[VCPU_REGS_RAX] = rdtsc_fake & -1u;
    vcpu->arch.regs[VCPU_REGS_RDX] = (rdtsc_fake >> 32) & -1u;

    return svm_skip_emulated_instruction(vcpu);
}

EOF
' arch/x86/kvm/svm/svm.c