[coreboot-gerrit] Change in coreboot[master]: emulation/qemu-i440fx,q35: avoid writing to ROM

[Julian Stecklina (Code Review)]

Julian Stecklina has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/59474 )

Change subject: emulation/qemu-i440fx,q35: avoid writing to ROM
......................................................................

emulation/qemu-i440fx,q35: avoid writing to ROM

libcbfs has a workaround to avoid writing to ROM areas:

/* Hacky way to not load programs over read only media. The stages
         * that would hit this path initialize themselves. */
        if ((ENV_BOOTBLOCK || ENV_SEPARATE_VERSTAGE) &&
            !CONFIG(NO_XIP_EARLY_STAGES) && CONFIG(BOOT_DEVICE_MEMORY_MAPPED)) {

This workaround is not triggered in Qemu, because
BOOT_DEVICE_MEMORY_MAPPED is only selected for SPI boot devices. This
results in confusing (to the VMM developer) writes to read-only
memory.

As far as I can tell, this issue is weird but harmless, because the
code does memcpy to ROM with source == destination. The concensus in
the mailing list thread [1] was that it's worthwhile to be fixed
regardless.

[1] https://mail.coreboot.org/hyperkitty/list/[e-mail]/message/KDI6...

Change-Id: I5cefbc31f917021236105f7dc969118d612ac399
Signed-off-by: Julian Stecklina 
---
M src/mainboard/emulation/qemu-i440fx/Kconfig
M src/mainboard/emulation/qemu-q35/Kconfig
2 files changed, 2 insertions(+), 0 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/74/59474/1

diff --git a/src/mainboard/emulation/qemu-i440fx/Kconfig b/src/mainboard/emulation/qemu-i440fx/Kconfig
index dd11092..436bb20 100644
--- a/src/mainboard/emulation/qemu-i440fx/Kconfig
+++ b/src/mainboard/emulation/qemu-i440fx/Kconfig
@@ -16,6 +16,7 @@
    select HAVE_ASAN_IN_ROMSTAGE
    select NO_SMM
    select BOOT_DEVICE_NOT_SPI_FLASH
+	select BOOT_DEVICE_MEMORY_MAPPED

config VBOOT
    select VBOOT_MUST_REQUEST_DISPLAY
diff --git a/src/mainboard/emulation/qemu-q35/Kconfig b/src/mainboard/emulation/qemu-q35/Kconfig
index 155540d..1fc82b5 100644
--- a/src/mainboard/emulation/qemu-q35/Kconfig
+++ b/src/mainboard/emulation/qemu-q35/Kconfig
@@ -16,6 +16,7 @@
    select MAINBOARD_HAS_CHROMEOS
    select SOUTHBRIDGE_INTEL_COMMON_ACPI_MADT
    select BOOT_DEVICE_NOT_SPI_FLASH
+	select BOOT_DEVICE_MEMORY_MAPPED

config VBOOT
    select VBOOT_MUST_REQUEST_DISPLAY