[Crash-utility] question about phys_base

[Dave Anderson]

----- Original Message -----
> >
> > OK, so then I don't understand what you mean by "may be the same"?
> >
> > You didn't answer my original question, but if I understand you  correctly,
> > it would be impossible for the qemu host to create a PT_LOAD segment that
> > describes an x86_64 guest's __START_KERNEL_map region, because the host
> > doesn't know that what kind of kernel the guest is running.
> 
> Yes. Even if the guest is linux, it is still impossible to do it.  Because
> the guest maybe in the second kernel.
> 
> qemu-dump walks all guest's page table and collect virtual address and
> physical address mapping. If the page is not used by guest, the virtual is set
> to 0.  I create PT_LOAD according to such mapping. So if the guest is linux,
> there may be a PT_LOAD segment that describes __START_KERNEL_map region.
> But the information stored in PT_LOAD maybe for the second kernel. If crash
> uses it, crash will see the second kernel, not the first kernel.

Just to be clear -- what do you mean by the "second" kernel?  Do you
mean that a guest kernel crashed guest, and did a kdump operation,
and that second kdump kernel failed somehow, and now you're trying
to do a "virsh dump" on the kdump kernel?

Dave