machine/qemuarm*: don't explicitly set vmalloc

In 5c6064 the qemuarm* machines gained vmalloc=256, because in testing
Bruce was seeing vmap allocation failures.

However, this parameter is in bytes, so the kernel was setting a minimal
vmalloc area of 16MiB:

[    0.000000] vmalloc area is too small, limiting to 16MiB

The default value is 240MiB[1] which is close to the value that Bruce
was presumably aiming for, so I don't believe we should be setting this
value explicitly.

[1] early_vmalloc(), https://elixir.bootlin.com/linux/latest/source/arch/arm/mm/mmu.c#L1170
Signed-off-by: Ross Burton <ross.burton@arm.com>
---
 meta/conf/machine/qemuarm.conf   | 2 --
 meta/conf/machine/qemuarmv5.conf | 1 -
 2 files changed, 3 deletions(-)

On Tue, Apr 18, 2023 at 11:59 AM Ross Burton <ross.burton@arm.com> wrote:
>
> In 5c6064 the qemuarm* machines gained vmalloc=256, because in testing
> Bruce was seeing vmap allocation failures.
>
> However, this parameter is in bytes, so the kernel was setting a minimal
> vmalloc area of 16MiB:
>
> [    0.000000] vmalloc area is too small, limiting to 16MiB
>
> The default value is 240MiB[1] which is close to the value that Bruce
> was presumably aiming for, so I don't believe we should be setting this
> value explicitly.

I was shooting for the minimum at the time, since in coordination with
the mem= and -m options to qemu, we were getting too large a vmalloc
size.

Setting that value (incorrectly) silenced the warnings .. I can't
recall if we added that "to small" warning to an allow list ?
Otherwise, the AB should have been having issues with that as well.

Either way, the kernel versions have changed enough, as have our boot
parameters. It is worth just letting it be the default again, and
seeing if anything breaks.

Bruce

>
> [1] early_vmalloc(), https://elixir.bootlin.com/linux/latest/source/arch/arm/mm/mmu.c#L1170
> Signed-off-by: Ross Burton <ross.burton@arm.com>
> ---
>  meta/conf/machine/qemuarm.conf   | 2 --
>  meta/conf/machine/qemuarmv5.conf | 1 -
>  2 files changed, 3 deletions(-)
>
> diff --git a/meta/conf/machine/qemuarm.conf b/meta/conf/machine/qemuarm.conf
> index c5234231e2e..aa9ce882035 100644
> --- a/meta/conf/machine/qemuarm.conf
> +++ b/meta/conf/machine/qemuarm.conf
> @@ -17,8 +17,6 @@ QB_SYSTEM_NAME = "qemu-system-arm"
>  QB_MACHINE = "-machine virt,highmem=off"
>  QB_CPU = "-cpu cortex-a15"
>  QB_SMP ?= "-smp 4"
> -# Standard Serial console
> -QB_KERNEL_CMDLINE_APPEND = "vmalloc=256"
>  # For graphics to work we need to define the VGA device as well as the necessary USB devices
>  QB_GRAPHICS = "-device virtio-gpu-pci"
>  QB_OPT_APPEND = "-device qemu-xhci -device usb-tablet -device usb-kbd"
> diff --git a/meta/conf/machine/qemuarmv5.conf b/meta/conf/machine/qemuarmv5.conf
> index 6e59e42c3ab..ef1b4ece230 100644
> --- a/meta/conf/machine/qemuarmv5.conf
> +++ b/meta/conf/machine/qemuarmv5.conf
> @@ -12,7 +12,6 @@ SERIAL_CONSOLES ?= "115200;ttyAMA0 115200;ttyAMA1"
>  # For runqemu
>  QB_SYSTEM_NAME = "qemu-system-arm"
>  QB_MACHINE = "-machine versatilepb"
> -QB_KERNEL_CMDLINE_APPEND = "vmalloc=256"
>  QB_GRAPHICS = "-device virtio-gpu-pci"
>  QB_OPT_APPEND = "-device qemu-xhci -device usb-tablet -device usb-kbd"
>  QB_DTB = "${@oe.utils.version_less_or_equal('PREFERRED_VERSION_linux-yocto', '4.7', '', 'zImage-versatile-pb.dtb', d)}"
> --
> 2.34.1
>