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>

3 files changed, 53 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;
 }
 
diff --git a/src/mainboard/emulation/qemu-q35/Makefile.inc b/src/mainboard/emulation/qemu-q35/Makefile.inc
index ddcf6da062..4bd91f0217 100644
--- a/src/mainboard/emulation/qemu-q35/Makefile.inc
+++ b/src/mainboard/emulation/qemu-q35/Makefile.inc
@@ -2,17 +2,21 @@ bootblock-y += bootblock.c
 
 romstage-y += ../qemu-i440fx/fw_cfg.c
 romstage-y += ../qemu-i440fx/memmap.c
+romstage-y += memmap.c
 
 postcar-y += ../qemu-i440fx/fw_cfg.c
 postcar-y += ../qemu-i440fx/memmap.c
 postcar-y += ../qemu-i440fx/exit_car.S
+postcar-y += memmap.c
 
 ramstage-y += ../qemu-i440fx/fw_cfg.c
 ramstage-y += ../qemu-i440fx/memmap.c
 ramstage-y += ../qemu-i440fx/northbridge.c
+ramstage-y += memmap.c
 
 verstage-$(CONFIG_CHROMEOS) += chromeos.c
 verstage-$(CONFIG_CHROMEOS) += ../qemu-i440fx/fw_cfg.c
 ramstage-$(CONFIG_CHROMEOS) += chromeos.c
 
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smi.c
+smm-$(CONFIG_HAVE_SMI_HANDLER) += memmap.c
diff --git a/src/mainboard/emulation/qemu-q35/memmap.c b/src/mainboard/emulation/qemu-q35/memmap.c
new file mode 100644
index 0000000000..a8b1433714
--- /dev/null
+++ b/src/mainboard/emulation/qemu-q35/memmap.c
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#define __SIMPLE_DEVICE__
+
+#include <console/console.h>
+#include <cpu/x86/smm.h>
+#include <device/pci_ops.h>
+#include <mainboard/emulation/qemu-i440fx/memory.h>
+#include <mainboard/emulation/qemu-i440fx/fw_cfg.h>
+
+#define EXT_TSEG_MBYTES	0x50
+
+#define SMRAMC	0x9d
+#define G_SMRAME	(1 << 3)
+#define D_LCK		(1 << 4)
+#define D_CLS		(1 << 5)
+#define D_OPEN		(1 << 6)
+#define ESMRAMC	0x9e
+#define T_EN		(1 << 0)
+#define TSEG_SZ_MASK	(3 << 1)
+#define H_SMRAME	(1 << 7)
+
+void smm_region(uintptr_t *start, size_t *size)
+{
+	uint8_t esmramc = pci_read_config8(PCI_DEV(0, 0, 0), ESMRAMC);
+
+	switch ((esmramc & TSEG_SZ_MASK) >> 1) {
+	case 0:
+		*size = 1 * MiB;
+		break;
+	case 1:
+		*size = 2 * MiB;
+		break;
+	case 2:
+		*size = 8 * MiB;
+		break;
+	default:
+		*size = pci_read_config16(PCI_DEV(0, 0, 0), EXT_TSEG_MBYTES) * MiB;
+	}
+
+	*start = qemu_get_memory_size() * KiB - *size;
+	printk(BIOS_SPEW, "SMM_BASE: 0x%08lx, SMM_SIZE: %zu MiB\n", *start, *size / MiB);
+}