+Alex, due to mention of 21e00fa55f3fd On 09/10/18 15:03, Marc-André Lureau wrote: > Hi > > On Mon, Sep 10, 2018 at 2:44 PM Dr. David Alan Gilbert > <dgilb...@redhat.com> wrote: >> (I didn't know about guest_phys_block* and would have probably just used >> qemu_ram_foreach_block ) >> > > guest_phys_block*() seems to fit, as it lists only the blocks actually > used, and already skip the device RAM. > > Laszlo, you wrote the functions > (https://git.qemu.org/?p=qemu.git;a=commit;h=c5d7f60f0614250bd925071e25220ce5958f75d0), > do you think it's appropriate to list the memory to clear, or we > should rather use qemu_ram_foreach_block() ?
Originally, I would have said, "use either, doesn't matter". Namely, when I introduced the guest_phys_block*() functions, the original purpose was not related to RAM *contents*, but to RAM *addresses* (GPAs). This is evident if you look at the direct child commit of c5d7f60f0614, namely 56c4bfb3f07f, which put GuestPhysBlockList to use. And, for your use case (= wiping RAM), GPAs don't matter, only contents matter. However, with the commits I mentioned previously, namely e4dc3f5909ab9 and 21e00fa55f3fd, we now filter out some RAM blocks from the dumping based on contents / backing as well. I think? So I believe we should honor that for the wiping to. I guess I'd (vaguely) suggest using guest_phys_block*(). (And then, as Dave suggests, maybe extend the filter to consider pmem too, separately.) Laszlo
