[coreboot-gerrit] Change in coreboot[master]: mb/emulation/qemu-i440fx: Reserve low memory

[Duncan Laurie (Code Review)]

Duncan Laurie has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/39834 )

Change subject: mb/emulation/qemu-i440fx: Reserve low memory
......................................................................

mb/emulation/qemu-i440fx: Reserve low memory

Ensure that the low memory is properly reserved so it does not get
marked as normal RAM and get wiped or reused by firmware or the kernel.
This ensures that the low RSDP is always available for the kernel.

Change-Id: I7295018416229bc957ecbf26f77623a57965557e
Signed-off-by: Duncan Laurie 
---
M src/mainboard/emulation/qemu-i440fx/northbridge.c
1 file changed, 6 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/34/39834/1

diff --git a/src/mainboard/emulation/qemu-i440fx/northbridge.c b/src/mainboard/emulation/qemu-i440fx/northbridge.c
index b30723d..7e067a4 100644
--- a/src/mainboard/emulation/qemu-i440fx/northbridge.c
+++ b/src/mainboard/emulation/qemu-i440fx/northbridge.c
@@ -129,6 +129,12 @@
    			   "debugcon");
    }

+	/* A segment is legacy VGA region */
+	mmio_resource(dev, idx++, 0xa0000 / KiB, (0xc0000 - 0xa0000) / KiB);
+
+	/* C segment to 1MB is reserved RAM (low tables) */
+	reserved_ram_resource(dev, idx++, 0xc0000 / KiB, (1*MiB - 0xc0000) / KiB);
+
    if (q35 && ((tomk * 1024) < 0xb0000000)) {
    	/*
    	 * Reserve the region between top-of-ram and the