On Thu, Jun 23, 2022 at 3:45 PM Atish Kumar Patra <ati...@rivosinc.com> wrote: > > On Wed, Jun 22, 2022 at 9:15 PM Alistair Francis <alistai...@gmail.com> wrote: > > > > On Wed, Jun 8, 2022 at 4:41 PM Bin Meng <bmeng...@gmail.com> wrote: > > > > > > +Atish > > > > > > On Wed, Jun 8, 2022 at 2:20 PM Alistair Francis > > > <alistair.fran...@opensource.wdc.com> wrote: > > > > > > > > From: Alistair Francis <alistair.fran...@wdc.com> > > > > > > > > We previously stored the device tree at a 16MB alignment from the end of > > > > memory (or 3GB). This means we need at least 16MB of memory to be able > > > > to do this. We don't actually need the FDT to be 16MB aligned, so let's > > > > drop it down to 2MB so that we can support systems with less memory, > > > > while also allowing FDT size expansion. > > > > > > > > Resolves: https://gitlab.com/qemu-project/qemu/-/issues/992 > > > > Signed-off-by: Alistair Francis <alistair.fran...@wdc.com> > > > > --- > > > > hw/riscv/boot.c | 4 ++-- > > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c > > > > index 57a41df8e9..e476d8f491 100644 > > > > --- a/hw/riscv/boot.c > > > > +++ b/hw/riscv/boot.c > > > > @@ -226,11 +226,11 @@ uint64_t riscv_load_fdt(hwaddr dram_base, > > > > uint64_t mem_size, void *fdt) > > > > /* > > > > * We should put fdt as far as possible to avoid kernel/initrd > > > > overwriting > > > > * its content. But it should be addressable by 32 bit system as > > > > well. > > > > - * Thus, put it at an 16MB aligned address that less than fdt size > > > > from the > > > > + * Thus, put it at an 2MB aligned address that less than fdt size > > > > from the > > > > * end of dram or 3GB whichever is lesser. > > > > */ > > > > temp = (dram_base < 3072 * MiB) ? MIN(dram_end, 3072 * MiB) : > > > > dram_end; > > > > - fdt_addr = QEMU_ALIGN_DOWN(temp - fdtsize, 16 * MiB); > > > > + fdt_addr = QEMU_ALIGN_DOWN(temp - fdtsize, 2 * MiB); > > > > > > > > > > @Atish Patra may have some pointers about the 16MiB alignment > > > requirement. > > > > Sorry. I missed this patch for some reason. 16MiB alignment was just > chosen as a safe option. > We couldn't put it at the end of DRAM and I just wanted to place it at > a reasonable distance. > > 2MB should be totally okay.
Can I get a review or Ack :) Alistair > > > Any thoughts? > > > > Alistair > > > > > > > > Regards, > > > Bin
