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Re: [Qemu-devel] [Question] dump memory when host pci device is used by
From: |
Wen Congyang |
Subject: |
Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest |
Date: |
Tue, 25 Oct 2011 09:37:08 +0800 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 |
At 10/24/2011 11:58 PM, Dave Anderson Write:
>
>
> ----- Original Message -----
>
>>>> No, an ELF image of the guest's physical memory.
>>>
>>> Well then that should be pretty straight forward to support. Depending upon
>>> how similar it would be to the "standard" kdump ELF format, the only other
>>> issue is how to determine the physical base address at which the kernel is
>>> loaded, in order to be able to translate the mapped kernel-text/static-data
>>> virtual region of the x86_64 arch (the __START_KERNEL_map region).
>>>
>>
>> I guess an elf note would work for that?
>
> Right -- here is an example of a RHEL6 ELF kdump header:
Hi, Jan
Is gdb standard core file like the following format? Does gdb support this
format?
If yes, I think the dump command can output the guest physical memory in
the following format, and we can use both gdb and crash to analyze it.
>
> $ readelf -a vmcore
> ELF Header:
> Magic: 7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
> Class: ELF64
> Data: 2's complement, little endian
> Version: 1 (current)
> OS/ABI: UNIX - System V
> ABI Version: 0
> Type: CORE (Core file)
> Machine: Advanced Micro Devices X86-64
> Version: 0x1
> Entry point address: 0x0
> Start of program headers: 64 (bytes into file)
> Start of section headers: 0 (bytes into file)
> Flags: 0x0
> Size of this header: 64 (bytes)
> Size of program headers: 56 (bytes)
> Number of program headers: 6
> Size of section headers: 0 (bytes)
> Number of section headers: 0
> Section header string table index: 0
>
> There are no sections in this file.
>
> There are no sections in this file.
>
> Program Headers:
> Type Offset VirtAddr PhysAddr
> FileSiz MemSiz Flags Align
> NOTE 0x0000000000000190 0x0000000000000000 0x0000000000000000
> 0x000000000000083c 0x000000000000083c 0
> LOAD 0x00000000000009cc 0xffffffff81000000 0x0000000001000000
> 0x0000000000ba3000 0x0000000000ba3000 RWE 0
> LOAD 0x0000000000ba39cc 0xffff810000000000 0x0000000000000000
> 0x00000000000a0000 0x00000000000a0000 RWE 0
> LOAD 0x0000000000c439cc 0xffff810000100000 0x0000000000100000
> 0x0000000001f00000 0x0000000001f00000 RWE 0
> LOAD 0x0000000002b439cc 0xffff81000a000000 0x000000000a000000
> 0x00000000c5fc2840 0x00000000c5fc2840 RWE 0
> LOAD 0x00000000c8b0620c 0xffff810100000000 0x0000000100000000
> 0x0000000030000000 0x0000000030000000 RWE 0
>
> There is no dynamic section in this file.
>
> There are no relocations in this file.
>
> There are no unwind sections in this file.
>
> No version information found in this file.
>
> Notes at offset 0x00000190 with length 0x0000083c:
> Owner Data size Description
> CORE 0x00000150 NT_PRSTATUS (prstatus structure)
> CORE 0x00000150 NT_PRSTATUS (prstatus structure)
> VMCOREINFO 0x0000055b Unknown note type: (0x00000000)
> $
>
> In this example, the phys_base (of zero) can be determined by looking
> at the first PT_LOAD segment, and comparing the PhysAddr and the VirtAddr
> values -- given that __START_KERNEL_map region is based at ffffffff800000000.
> The remaining physical memory chunks are described by the subsequent
> unity-mapped segments.
>
> The NT_PRSTATUS notes are register dumps of each cpu, where this vmcore
> was from a 2-cpu system. But the crash utility is capable of surviving
> without them. It can also get by without the VMCOREINFO note, which is
> primarily there for use by the "makedumpfile" utility, which is used to
> compress ELF kdumps and filter out unwanted pages, and then make a different
> dumpfile format entirely.
>
> This may be another stupid question -- but does the guest failure mode
> render it incapable of using kdump?
Guest failure mode? I do not what does it mean. But 'virsh dump' can be used
when kdump fails or kdump service is not started.
Thanks
Wen Congyang
>
> 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, 2011/10/21
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Dave Anderson, 2011/10/21
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Jan Kiszka, 2011/10/21
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Richard W.M. Jones, 2011/10/21
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Wen Congyang, 2011/10/23
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Dave Anderson, 2011/10/24
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Avi Kivity, 2011/10/24
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Dave Anderson, 2011/10/24
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Avi Kivity, 2011/10/24
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest, Dave Anderson, 2011/10/24
- Re: [Qemu-devel] [Question] dump memory when host pci device is used by guest,
Wen Congyang <=
- 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, 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, 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, Daniel P. Berrange, 2011/10/18