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 <imamm...@redhat.com>: > On Mon, 19 Jul 2021 12:01:10 +0200 > Philippe Mathieu-Daudé <f4...@amsat.org> 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 0x20000000 0x1000000 /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. > > > >
