[PATCH] qemu: handle e820 ram entries

[Gerd Hoffmann]

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;
+            }
             add_e820(entry.address, entry.length, entry.type);
         }
     } else if (runningOnKVM()) {