On Tuesday 12 Jan 2021 at 09:53:36 (-0600), Rob Herring wrote: > On Tue, Jan 12, 2021 at 8:26 AM Quentin Perret <qperret@xxxxxxxxxx> wrote: > > > > On Tuesday 12 Jan 2021 at 08:10:47 (-0600), Rob Herring wrote: > > > On Tue, Jan 12, 2021 at 3:51 AM Quentin Perret <qperret@xxxxxxxxxx> wrote: > > > > > > > > On Monday 11 Jan 2021 at 08:45:10 (-0600), Rob Herring wrote: > > > > > On Fri, Jan 8, 2021 at 6:16 AM Quentin Perret <qperret@xxxxxxxxxx> wrote: > > > > > > > > > > > > Introduce early_init_dt_add_memory_hyp() to allow KVM to conserve a copy > > > > > > of the memory regions parsed from DT. This will be needed in the context > > > > > > of the protected nVHE feature of KVM/arm64 where the code running at EL2 > > > > > > will be cleanly separated from the host kernel during boot, and will > > > > > > need its own representation of memory. > > > > > > > > > > What happened to doing this with memblock? > > > > > > > > I gave it a go, but as mentioned in v1, I ran into issues for nomap > > > > regions. I want the hypervisor to know about these memory regions (it's > > > > possible some of those will be given to protected guests for instance) > > > > but these seem to be entirely removed from the memblocks when using DT: > > > > > > > > https://elixir.bootlin.com/linux/latest/source/drivers/of/fdt.c#L1153 > > > > > > > > EFI appears to do things differently, though, as it 'just' uses > > > > memblock_mark_nomap() instead of actively removing the memblock. And that > > > > means I could actually use the memblock API for EFI, but I'd rather > > > > have a common solution. I tried to understand why things are done > > > > differently but couldn't find an answer and kept things simple and > > > > working for now. > > > > > > > > Is there a good reason for not using memblock_mark_nomap() with DT? If > > > > not, I'm happy to try that. > > > > > > There were 2 patches to do that, but it never got resolved. See here[1]. > > > > Thanks. So the DT stuff predates the introduction of memblock_mark_nomap, > > that's why... > > > > By reading the discussions, [1] still looks a sensible patch on its own, > > independently from the issue Nicolas tried to solve. Any reason for not > > applying it? > > As I mentioned in the thread, same patch with 2 different reasons. So > I just wanted a better commit message covering both. Sorry if I'm being thick, but I'm not seeing it. How are they the same? IIUC, as per Nicolas' last reply, using memblock_mark_nomap() does not solve his issue with a broken DT. These 2 patches address two completely separate issues no? Thanks, Quentin
