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Re: [Qemu-devel] [Question] dump memory when host pci device is used by
From: |
Dave Anderson |
Subject: |
Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest |
Date: |
Tue, 25 Oct 2011 09:18:09 -0400 (EDT) |
----- Original Message -----
> On 10/25/2011 10:23 AM, Avi Kivity wrote:
> > On 10/25/2011 10:06 AM, Wen Congyang wrote:
> >> Hi, Avi Kivity, Dave Anderson
> >>
> >> I have two questions about it:
> >>
> >> 1. How to know the guest's physical base address in qemu?
> >
> > In fact, it's impossible.
> >
> > Perhaps crash can scan through the core looking for a signature. Need
> > to be careful since multiple signatures may be detected (a kdump kernel,
> > a kernel image in pagecache, or a nested guest).
>
> Crash uses a heuristic based on the IDT base to identify the base from
> migrate-to-file output. It also needs CR3 in order to read from virtual
> address.
Just to clarify -- the need for the IDT base and cr3 is *only* true for
KVM dumps using the "savevm" format.
With ELF-format kdumps, the phys_base is simply determined from the PT_LOAD
segment that describes the kernel's __START_KERNEL_map region. I don't know
why that couldn't be done in this proposed case.
Dave
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, (continued)
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Wen Congyang, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Avi Kivity, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Paolo Bonzini, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Avi Kivity, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Paolo Bonzini, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest,
Dave Anderson <=
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Avi Kivity, 2011/10/25
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Daniel P. Berrange, 2011/10/18
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/18
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/18
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Daniel P. Berrange, 2011/10/18
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/18
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Daniel P. Berrange, 2011/10/10
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Daniel P. Berrange, 2011/10/10
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Richard W.M. Jones, 2011/10/10
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/10