Thank you, guys!
Generic loader and pmemsave are so useful for me!
But, I have another question.
I would like to reset a memory region initialized generic loader during
qemu running.
I know the reset APIs such as resettable_cold_reset_fn,
but I think these APIs can't use to reset the MemoryRegion because it does
not have ResettableState.
Are there any methods to reset MemoryRegion?
2021年7月19日(月) 22:03 Igor Mammedov :
> On Mon, 19 Jul 2021 12:01:10 +0200
> Philippe Mathieu-Daudé wrote:
>
> > Hi Hiroko,
> >
> > On 7/19/21 11:34 AM, Hiroko Shimizu wrote:
> > > Hello,
> > > I'd like to initialize RAM from a specific file when RAM is created.
> > > Then, I tried using memory_region_init_ram_from_file().
> ...
> > > Could you tell me what I need to do or another way to initialize RAM
> > > from a file?
> > >
> > > Also, is it possible to save RAM's value to the file when a value is
> > > written to RAM which is initialized
> memory_region_init_ram_from_file()?
> >
> > 2 years ago I was using -mem-path /dev/shm/ (and maybe -mem-prealloc) to
> > keep the ram sync on a file, pause the VM and analyse the memory, but it
> > stopped working after the global memdev refactor. I don't think my use
>
> -mem-path should still work as it's aliased to default memdev,
> (see: create_default_memdev), that's assumes legacy CLI and that
> board uses MachineState::ram as RAM.
> (it certainly worked on mainstream boards, if you share your CLI
> I can look if it's expected or a bug).
>
> For new CLI:
> it's recommended to use '-machine memory-backend=' which points to
> previously
> specified file backend, ex:
>
> -object
> memory-backend-file,id=myram,share=yes,size=1G,mem-path=/ram-image-file \
> -machine memory-backend=myram
>
> Above will create memory region and assign it to MachineState::ram,
> so one should use that instead of manually calling
> memory_region_init_ram_from_file().
>
>
> > case was the expected one. Maybe I simply need to adapt to a new command
> > line format :)
> >
> > Now I use 'pmemsave' from the monitor:
> >
> > pmemsave addr size file -- save to disk physical memory dump starting at
> > 'addr' of size 'size'
> >
> > If attached from GDB:
> >
> > (gdb) monitor pmemsave 0x2000 0x100 /tmp/ram.dump
> >
> > There are other commands and probably a clever way to do that.
> >
> > See also the VM snapshot feature, described here, which might be
> > what you are looking for:
> >
> https://translatedcode.wordpress.com/2015/07/06/tricks-for-debugging-qemu-savevm-snapshots/
> >
> > Regards,
> >
> > Phil.
> >
>
>
