diff options
| author | Patrick Rudolph <patrick.rudolph@9elements.com> | 2021-01-07 14:12:38 +0100 |
|---|---|---|
| committer | Patrick Georgi <pgeorgi@google.com> | 2021-01-11 07:34:19 +0000 |
| commit | 82e111cc2a8795cefca36e57031d3d2da0f919aa (patch) | |
| tree | aaf35e40a351cc1d945129af8d19a27750f8df2c /src/mainboard/emulation/qemu-q35 | |
| parent | cbfe4ba76ad9d9f43bef2c366b180c5d594a0703 (diff) | |
mb/emulation/qemu: Copy page tables to DRAM in assembly
To work around various bugs running KVM enabled, copy page tables to
DRAM in assembly before jumping to x86_64 mode.
Tested on QEMU using KVM, no more stange bugs happen:
Tested on host
- CPU Intel(R) Core(TM) i7-7700HQ
- Linux 5.9
- qemu 4.2.1
Used to crash on emulating MMX instructions and failed to translate
some addresses using the virtual MMU when running in long mode.
Tested on host
- CPU AMD EPYC 7401P 24-Core Processor
- Linux 5.4
- qemu 4.2.1
Used to crash on jumping to long mode.
Change-Id: Ic0bdd2bef7197edd2e7488a8efdeba7eb4ab0dd4
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/49228
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Diffstat (limited to 'src/mainboard/emulation/qemu-q35')
| -rw-r--r-- | src/mainboard/emulation/qemu-q35/Kconfig | 9 | ||||
| -rw-r--r-- | src/mainboard/emulation/qemu-q35/mainboard.c | 6 |
2 files changed, 15 insertions, 0 deletions
diff --git a/src/mainboard/emulation/qemu-q35/Kconfig b/src/mainboard/emulation/qemu-q35/Kconfig index edd2b2c6d6..d88d0da7ff 100644 --- a/src/mainboard/emulation/qemu-q35/Kconfig +++ b/src/mainboard/emulation/qemu-q35/Kconfig @@ -32,6 +32,15 @@ config FMDFILE default "src/mainboard/\$(CONFIG_MAINBOARD_DIR)/vboot-rwa-16M.fmd" if VBOOT_SLOTS_RW_A && !VBOOT_SLOTS_RW_AB default "src/mainboard/\$(CONFIG_MAINBOARD_DIR)/vboot-rwab-16M.fmd" if VBOOT_SLOTS_RW_AB +if ARCH_BOOTBLOCK_X86_64 +# Need to install page tables in DRAM as the virtual MMU has problems translating paging +# request when the page table resides in emulated ROM. This causes undefined behaviour +# when handling data requests, as well as fetching and decoding instructions +# Real hardware didn't show any problems until now. +config ARCH_X86_64_PGTBL_LOC + default 0x8000 +endif + if VBOOT config VBOOT_SLOTS_RW_A diff --git a/src/mainboard/emulation/qemu-q35/mainboard.c b/src/mainboard/emulation/qemu-q35/mainboard.c index d329e5affb..c88874f4f2 100644 --- a/src/mainboard/emulation/qemu-q35/mainboard.c +++ b/src/mainboard/emulation/qemu-q35/mainboard.c @@ -44,6 +44,12 @@ static void qemu_nb_read_resources(struct device *dev) /* reserve mmconfig */ fixed_mem_resource(dev, 2, CONFIG_MMCONF_BASE_ADDRESS >> 10, 0x10000000 >> 10, IORESOURCE_RESERVE); + + if (CONFIG(ARCH_RAMSTAGE_X86_64)) { + /* Reserve page tables in DRAM. FIXME: Remove once x86_64 page tables reside in CBMEM */ + reserved_ram_resource(dev, 0, CONFIG_ARCH_X86_64_PGTBL_LOC / KiB, + (6 * 0x1000) / KiB); + } } |