On 2/16/25 21:43, Simon Glass wrote:
U-Boot can start and boot an OS in both qemu-x86 and qemu-x86_64 but it
is not perfect.
With both builds, executing the VESA ROM causes an intermittent hang, at
least on some AMD CPUs.
With qemu-x86_64 kvm cannot be used since the move to long mode (64-bit)
is done in a way that works on real hardware but not with QEMU. This
means that performance is 4-5x slower than it could be, at least on my
CPU.
Do you have a reproducer for this? It shouldn't happen... also, do you
know if this is broken for both Intel and AMD CPUs?
Thanks,
Paolo
We can work around the first problem by using Bochs, which is anyway a
better choice than VESA for QEMU. The second can be addressed by using
the same descriptor across the jump to long mode.
With an MTRR fix this allows booting into Ubuntu on qemu-x86_64
Changes in v2:
- Redo commit message
- Add new patch to rename the _D dirty flag
- Add new patch to support CPU functions in long mode
- Add new patch to tidy up address size in MTRR calculations
- Add new patch with a 64-bit version of is_power_of_2()
- Add new patch to set an MTRR for the RAM in QEMU
- Add new patch with a helper to send characters
- Add new patch to allow tests to be filtered by role
- Add more patches to support booting with kvm
- Add new patch with a test for booting Ubuntu 24.04
Simon Glass (28):
x86: Expand x86_64 early memory
x86: qemu: Switch to bochs display
x86: qemu: Enable dhrystone
x86: qemu: Avoid accessing BSS too early
x86: Drop mpspec from the SPL build
x86: Add some log categories
x86: Drop use of CONFIG_REALMODE_DEBUG
x86: Avoid clearing the VESA display
x86: Add 64-bit entries to the GDT
x86: Use defines for the cache flags
x86: spl: Drop duplicate CPU init
x86: Drop the message about features missing in 64-bit
x86: Include stdbool.h in interrupt header
x86: Tidy up the GDT size in start/16.S
x86: Disable paging before changing to long mode
x86: Use the same GDT when jumping to long mode
x86: Use a simple jump into long mode
x86: Rename the _D dirty flag
x86: Support CPU functions in long mode
x86: Tidy up address size in MTRR calculations
Add a 64-bit version of is_power_of_2()
x86: Support MTRRs of 4GB on 32-bit machines
x86: emulation: Set an MTRR for the RAM
scripts: Expand a few options
test/py: Add a helper to send characters
test/py: Allow tests to be filtered by role
RFC: test/py: Deal with timeouts
test: Add a test for booting Ubuntu 24.04
.gitlab-ci.yml | 5 +++
arch/x86/cpu/cpu.c | 24 +++++++++++++++
arch/x86/cpu/i386/call64.S | 35 +++++++++------------
arch/x86/cpu/i386/cpu.c | 41 +++++++++---------------
arch/x86/cpu/mtrr.c | 12 +++++---
arch/x86/cpu/qemu/dram.c | 15 +++++++++
arch/x86/cpu/qemu/qemu.c | 20 ++++++++----
arch/x86/cpu/start.S | 4 ++-
arch/x86/cpu/start16.S | 3 +-
arch/x86/cpu/x86_64/cpu.c | 5 ---
arch/x86/include/asm/cpu.h | 35 ++++++++++++++++++---
arch/x86/include/asm/interrupt.h | 1 +
arch/x86/include/asm/processor.h | 5 ++-
arch/x86/lib/Makefile | 2 ++
arch/x86/lib/bios.c | 27 +++++++++-------
arch/x86/lib/bios_interrupts.c | 8 ++---
arch/x86/lib/i8259.c | 2 ++
arch/x86/lib/spl.c | 4 +--
configs/qemu-x86_64_defconfig | 10 +++---
configs/qemu-x86_defconfig | 6 ++--
include/linux/log2.h | 6 ++++
scripts/build-qemu.sh | 4 +--
test/py/conftest.py | 22 +++++++++++++
test/py/console_base.py | 33 ++++++++++++--------
test/py/pytest.ini | 1 +
test/py/tests/test_distro.py | 53 ++++++++++++++++++++++++++++++++
test/py/tests/test_sleep.py | 1 +
27 files changed, 273 insertions(+), 111 deletions(-)
create mode 100644 test/py/tests/test_distro.py
