Hi,
I am a student. And my teacher told me to monitor every process in guest.
So, I try to intercept every Cr3 access. However, if kvm is loaded
with EPT enable, Acesses to Cr3 would not cause VM-exit.
I modified the code to change vmcs configuration.
To be specific, these functions are rewirted.
static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
unsigned long cr0,
struct kvm_vcpu *vcpu)
{
....
} else if (!is_paging(vcpu)) {
/* From nonpaging to paging */
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
- ~(CPU_BASED_CR3_LOAD_EXITING |
+ ~( // CPU_BASED_CR3_LOAD_EXITING|
CPU_BASED_CR3_STORE_EXITING));
....
}
static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
{
...
if (_cpu_based_2nd_exec_control & SECONDARY_EXEC_ENABLE_EPT) {
/* CR3 accesses and invlpg don't need to cause VM Exits when EPT
enabled */
- _cpu_based_exec_control &= ~(CPU_BASED_CR3_LOAD_EXITING |
+ _cpu_based_exec_control &= ~( //
CPU_BASED_CR3_LOAD_EXITING |
CPU_BASED_CR3_STORE_EXITING |
CPU_BASED_INVLPG_EXITING);
....
}
I though it can force every Cr3 access to be trapped with EPT enable.
However, VM seems to fail to boot when it changes from nonpaging to
paging.
Do U guys have any idea? Or Can someone tell me how can I intercept
Cr3 access and why can not it work?
Thank U for answering.
--
Thanks
Rui Wu
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