[PATCH v2] qemu-arm: round down memory to multiple of 2MB for LPAE

[Tom Rini]

On Thu, Feb 01, 2024 at 01:40:54PM +0100, Igor Opaniuk wrote:

> QEMU's -m option can take fractional megabyte values,
> and lowest granularity seems to be 0x2000.
> For example, run qemu with amount of memory set to 100005k (0x61A9400):
> 
> $ qemu-system-arm -machine virt -cpu cortex-a15 -m 100005k \
> -bios denx/u-boot.bin -nographic
> 
> => fdt addr $fdt_addr
> => fdt print /memory at 40000000
> memory at 40000000 {
>         reg = <0x00000000 0x40000000 0x00000000 0x061aa000>;
>         device_type = "memory";
> };
> 
> When LPAE is enabled, 1:1 mapping is created using 2 MB blocks.
> In case amount of memory provided to QEMU is not multiple
> of 2 MB, hang occurs during MMU initialization.
> 
> How to reproduce:
> qemu-system-arm -machine virt -m 1058 -nographic -bios u-boot.bin - boots
> qemu-system-arm -machine virt -m 1057 -nographic -bios u-boot.bin - hangs
> 
> DRAM:  1 GiB
> initcall: 60011df8
> initcall: 60011904
> New Stack Pointer is: 80fffe90
> initcall: 60011a20
> initcall: 60011bcc
> initcall: 60011bd4
> initcall: 600119b4
> Relocation Offset is: 22042000
> Relocating to 82042000, new gd at 81001ed0, sp at 80fffe90
> initcall: 60011b8c
> initcall: 82053ea0
> initcall: 82053ea8
> initcall: 60012040 (relocated to 82054040)
> dram_bank_mmu_setup: bank: 0
> - hang here during mmu init -
> 
> This patches rounds down to the nearest multiple of 2MB when
> CONFIG_ARMV7_LPAE=y.
> 
> Fixes: 3fa914af82("arm: qemu: implement enable_caches()")
> Signed-off-by: Igor Opaniuk <igor.opaniuk at foundries.io>
> Reviewed-by: Oleksandr Suvorov <oleksandr.suvorov at foundries.io

Applied to u-boot/next, thanks!

-- 
Tom
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