On Thu, Sep 29, 2016 at 2:24 AM, Markus Armbruster <arm...@redhat.com> wrote: > Alistair Francis <alistair.fran...@xilinx.com> writes: > >> Signed-off-by: Alistair Francis <alistair.fran...@xilinx.com> >> Reviewed-by: Peter Maydell <peter.mayd...@linaro.org> >> --- >> V11: >> - Fix corrections >> V10: >> - Split the data loading and PC setting >> V9: >> - Clarify the image loading options >> V8: >> - Improve documentation >> V6: >> - Fixup documentation >> V4: >> - Re-write to be more comprehensive >> >> docs/generic-loader.txt | 81 >> +++++++++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 81 insertions(+) >> create mode 100644 docs/generic-loader.txt >> >> diff --git a/docs/generic-loader.txt b/docs/generic-loader.txt >> new file mode 100644 >> index 0000000..d1f8ce3 >> --- /dev/null >> +++ b/docs/generic-loader.txt >> @@ -0,0 +1,81 @@ >> +Copyright (c) 2016 Xilinx Inc. >> + >> +This work is licensed under the terms of the GNU GPL, version 2 or later. >> See >> +the COPYING file in the top-level directory. >> + >> + >> +The 'loader' device allows the user to load multiple images or values into >> +QEMU at startup. >> + >> +Loading Data into Memory Values >> +--------------------- >> +The loader device allows memory values to be set from the command line. This >> +can be done by following the syntax below: >> + >> + -device loader,addr=<addr>,data=<data>,data-len=<data-len> >> + [,data-be=<data-be>][,cpu-num=<cpu-num>] >> + >> + <addr> - The address to store the data in. >> + <data> - The value to be written to the address. The maximum size >> of >> + the data is 8 bytes. >> + <data-len> - The length of the data in bytes. This argument must be >> + included if the data argument is. >> + <data-be> - Set to true if the data to be stored on the guest should >> be >> + written as big endian data. The default is to write little >> + endian data. >> + <cpu-num> - The number of the CPU's address space where the data >> should >> + be loaded. If not specified the address space of the first >> + CPU is used. >> + >> +For all values both hex and decimal values are allowed. By default the >> values >> +will be parsed as decimal. To use hex values the user should prefix the >> number >> +with a '0x'. > > Unless you bypassed QemuOpts number parsing somehow, octal works as > well. In case you did bypass: don't! Command line consistency matters. > Follow-up patch reverting the bypass would be required. > > Not sure we want to document QemuOpts number syntax everywhere we > explain how a certain feature uses the command line. A pointer to the > canonical place could be better. Anyway, not something that needs > fixing before we commit.
I didn't bypass it, octal should work as well. I have clarified that a bit in the doc. > >> + >> +An example of loading value 0x8000000e to address 0xfd1a0104 is: >> + -device loader,addr=0xfd1a0104,data=0x8000000e,data-len=4 >> + >> +Setting a CPU's Program Counter >> +--------------------- >> +The loader device allows the CPU's PC to be set from the command line. This >> +can be done by following the syntax below: >> + >> + -device loader,addr=<addr>,cpu-num=<cpu-num> >> + >> + <addr> - The value to use as the CPU's PC. >> + <cpu-num> - The number of the CPU whose PC should be set to the >> + specified value. >> + >> +For all values both hex and decimal values are allowed. By default the >> values >> +will be parsed as decimal. To use hex values the user should prefix the >> number >> +with a '0x'. >> + >> +An example of setting CPU 0's PC to 0x8000 is: >> + -device loader,addr=0x8000,cpu-num=0 >> + >> +Loading Files >> +--------------------- >> +The loader device also allows files to be loaded into memory. This can be >> done >> +similarly to setting memory values. The syntax is shown below: >> + >> + -device >> loader,file=<file>[,addr=<addr>][,cpu-num=<cpu-num>][,force-raw=<raw>] >> + >> + <file> - A file to be loaded into memory >> + <addr> - The addr in memory that the file should be loaded. This is >> + ignored if you are using an ELF (unless force-raw is >> true). >> + This is required if you aren't loading an ELF. >> + <cpu-num> - This specifies the CPU that should be used. This is an >> + optional argument and will cause the CPU's PC to be set to >> + where the image is stored or in the case of an ELF file to >> + the value in the header. This option should only be used >> + for the boot image. >> + This will also cause the image to be written to the >> specified >> + CPU's address space. If not specified, the default is CPU >> 0. > > Using @cpu-num both for further specifying the meaning of @addr and for > setting that CPU's PC is awkward. Are you sure there will never be a > use case where you need to specify the CPU without also setting its PC? > > To be clear: while I feel this is a question we must discuss and > resolve, I don't think we need to hold the series for it. I agree that this can occur. Internally in the loader framework is a set_pc variable. In the future we can make this user accessible and then allow that to decide if the PC should be set or not. > >> + <force-raw> - Forces the file to be treated as a raw image. This can be >> + used to specify the load address of ELF files. > > "Specifying the load address of an ELF file" sounds like loading a > position-independent ELF file at a particular address. But I guess this > is actually for loading a file raw even though it is recognized by QEMU > as ELF. This option basically does make an ELF file position-independent as the user can control where it is loaded. > >> + >> +For all values both hex and decimal values are allowed. By default the >> values >> +will be parsed as decimal. To use hex values the user should prefix the >> number >> +with a '0x'. >> + >> +An example of loading an ELF file which CPU0 will boot is shown below: >> + -device loader,file=./images/boot.elf,cpu-num=0 > > Naive question: if you want to more than one thing (where "thing" is one > of the three cases described above), do you need a separate -device for > each, or can you combine them into one? You can't really squash them together. If you wanted to set two registers, you would need two commands. Thanks, Alistair > > > Again, while my questions may lead to improvements, they can be applied > on top. >