Re: [SeaBIOS] [PATCH] qemu: handle e820 ram entries

[Igor Mammedov]

On Mon, 14 Oct 2013 10:28:08 +0200
Gerd Hoffmann  wrote:
> Check the e820 entries we get from qemu for ram entries and handle them
> accordingly:
>
> (1) Entries overlapping with the lowmem range will be ignored.
>      At least initially qemu will not send such entries for
>      compatibility reasons.  That may change in the future though
>      if qemu needs a more recent seabios versions anyway for some
>      reason.  So better be prepared.
>  (2) Adjust RamSizeOver4G variable if we find it being too small.
>      Needed for guests with more that 1TB (this is the max amount
>      of memory the three-byte cmmos interface can represent).
> Signed-off-by: Gerd Hoffmann
>
> src/fw/paravirt.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/src/fw/paravirt.c b/src/fw/paravirt.c
> index c118480..c1469ae 100644
> --- a/src/fw/paravirt.c
> +++ b/src/fw/paravirt.c
> @@ -285,6 +285,15 @@ qemu_cfg_legacy(void)
>          int i;
>          for (i = 0; i < count32; i++) {
>              qemu_cfg_read(&entry, sizeof(entry));
>        if (entry.type == E820_RAM) {
>            if (entry.address < RamSize)
>                // ignore, we got it from cmos already and
>                // adding this again would ruin any reservations
>                // done so far
>                continue;
>            if (0x100000000LL + RamSizeOver4G < entry.address + entry.length)
>                RamSizeOver4G = entry.address + entry.length - 0x100000000LL;

it's all based on assumption that there is only one highmem entry,
why don't take just entry.length then?
>        }
>        add_e820(entry.address, entry.length, entry.type);
>    }
> } else if (runningOnKVM()) {