I am trying to read the value of cr3 from a VCPU assigned to a Dom U. I am invoking a custom hypercall and then attempting to read the value of
cr3 in the hypercall handler. Below is the code of my hypercall handler.
Here I am creating an object of the vcpu_guest_context and trying to read the value of
xen_cr3_to_pfn macro. But I am getting the value of this (i.e. pgdaddr) as 0. Can anyone please tell me what am I doing wrong here.??
I also found a function called read_cr3(). And I am getting some 8 bit values for this function e.g.
27ca4000. Does this look right??
Also then what is the difference between read_cr3 and xen_cr3_to_pfn. I read in some documentation that read_cr3 is not reliable hence use xen_cr3_to_pfn.
unsigned long CR3;
unsigned long pgdaddr;
printk ("Successfull Hypercall made to __HYPERVISOR_jeet1\n");
CR3 = read_cr3();
pgdaddr = xen_cr3_to_pfn(ctx.ctrlreg);
printk ("CR3:%lx\n", CR3);
printk ("PGDADDR:%lx\n", pgdaddr);