mb/emulation/qemu-q35: Account for TSEG

TSEG is located below TOLUD. The size is configured in ESMRAMC but can
also be configured with "-global mch.extended-tseg-mbytes=5" command
line argument. Note that the size in ESMRAMC needs to be 'invalid' (3)
for this to take action.

coreboot will leave TSEG at the default 1MiB.

Note that even if TSEG does not end up being used, it is likely a good
idea to not put anything there as if SMM gets locked down by something
else it will suddenly be inaccessible.

Change-Id: I5fd82a42d6602f1369bb3c69556c46f537542705
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/48236
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/mainboard/emulation/qemu-i440fx/memmap.c b/src/mainboard/emulation/qemu-i440fx/memmap.c
index b30b3816c5..75ab352b69 100644
--- a/src/mainboard/emulation/qemu-i440fx/memmap.c
+++ b/src/mainboard/emulation/qemu-i440fx/memmap.c
@@ -4,6 +4,7 @@
 #include <arch/io.h>
 #include <arch/romstage.h>
 #include <console/console.h>
+#include <cpu/x86/smm.h>
 #include "memory.h"
 #include "fw_cfg.h"
 
@@ -50,6 +51,11 @@ void *cbmem_top_chipset(void)
 		top = (uintptr_t)qemu_get_memory_size() * 1024;
 	}
 
+	if (CONFIG(BOARD_EMULATION_QEMU_X86_Q35)) {
+		size_t smm_size;
+		smm_region(&top, &smm_size);
+	}
+
 	return (void *)top;
 }