jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
1Copyright (c) 2016 Xilinx Inc.
2
3This work is licensed under the terms of the GNU GPL, version 2 or later. See
4the COPYING file in the top-level directory.
5
6
7The 'loader' device allows the user to load multiple images or values into
8QEMU at startup.
9
10Loading Data into Memory Values
11-------------------------------
12The loader device allows memory values to be set from the command line. This
13can be done by following the syntax below:
14
15 -device loader,addr=<addr>,data=<data>,data-len=<data-len>
16 [,data-be=<data-be>][,cpu-num=<cpu-num>]
17
18 <addr> - The address to store the data in.
19 <data> - The value to be written to the address. The maximum size of
20 the data is 8 bytes.
21 <data-len> - The length of the data in bytes. This argument must be
22 included if the data argument is.
23 <data-be> - Set to true if the data to be stored on the guest should be
24 written as big endian data. The default is to write little
25 endian data.
26 <cpu-num> - The number of the CPU's address space where the data should
27 be loaded. If not specified the address space of the first
28 CPU is used.
29
30All values are parsed using the standard QemuOps parsing. This allows the user
31to specify any values in any format supported. By default the values
32will be parsed as decimal. To use hex values the user should prefix the number
33with a '0x'.
34
35An example of loading value 0x8000000e to address 0xfd1a0104 is:
36 -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4
37
38Setting a CPU's Program Counter
39-------------------------------
40The loader device allows the CPU's PC to be set from the command line. This
41can be done by following the syntax below:
42
43 -device loader,addr=<addr>,cpu-num=<cpu-num>
44
45 <addr> - The value to use as the CPU's PC.
46 <cpu-num> - The number of the CPU whose PC should be set to the
47 specified value.
48
49All values are parsed using the standard QemuOps parsing. This allows the user
50to specify any values in any format supported. By default the values
51will be parsed as decimal. To use hex values the user should prefix the number
52with a '0x'.
53
54An example of setting CPU 0's PC to 0x8000 is:
55 -device loader,addr=0x8000,cpu-num=0
56
57Loading Files
58-------------
59The loader device also allows files to be loaded into memory. It can load ELF,
60U-Boot, and Intel HEX executable formats as well as raw images. The syntax is
61shown below:
62
63 -device loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>]
64
65 <file> - A file to be loaded into memory
66 <addr> - The memory address where the file should be loaded. This is
67 required for raw images and ignored for non-raw files.
68 <cpu-num> - This specifies the CPU that should be used. This is an
69 optional argument and will cause the CPU's PC to be set to
70 the memory address where the raw file is loaded or the entry
71 point specified in the executable format header. This option
72 should only be used for the boot image.
73 This will also cause the image to be written to the specified
74 CPU's address space. If not specified, the default is CPU 0.
75 <force-raw> - Setting force-raw=on forces the file to be treated as a raw
76 image. This can be used to load supported executable formats
77 as if they were raw.
78
79All values are parsed using the standard QemuOps parsing. This allows the user
80to specify any values in any format supported. By default the values
81will be parsed as decimal. To use hex values the user should prefix the number
82with a '0x'.
83
84An example of loading an ELF file which CPU0 will boot is shown below:
85 -device loader,file=./images/boot.elf,cpu-num=0
86
87Restrictions and ToDos
88----------------------
89 - At the moment it is just assumed that if you specify a cpu-num then you
90 want to set the PC as well. This might not always be the case. In future
91 the internal state 'set_pc' (which exists in the generic loader now) should
92 be exposed to the user so that they can choose if the PC is set or not.