On Sat, Feb 08, 2025 at 12:57:23PM -0800, Richard Henderson wrote:
> For system mode, we can rarely support the amount of RAM that
> the guest requires. TCG emulation is restricted to round-robin
> mode, which solves many of the atomicity issues, but not those
> associated with virtio. In any case, round-robin does nothing
> to help the speed of emulation.
>
> For user mode, most emulation does not succeed at all. Most
> of the time we cannot even load 64-bit non-PIE binaries due
> to lack of a 64-bit address space. Threads are run in
> parallel, not round-robin, which means that atomicity
> is not handled.
>
> Reviewed-by: Thomas Huth <th...@redhat.com>
> Reviewed-by: Philippe Mathieu-Daudé <phi...@linaro.org>
> Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
> ---
> meson.build | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
Shouldn't this patch and the earlier ones in this series have
added something to removed-features.rst, as this is a significant
feature removal which is impacting downstream users, and distros
in particular.
>
> diff --git a/meson.build b/meson.build
> index 85317cd63f..ec51827f40 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -3185,6 +3185,9 @@ if host_os == 'windows'
> endif
> endif
>
> +# Detect host pointer size for the target configuration loop.
> +host_long_bits = cc.sizeof('void *') * 8
> +
> ########################
> # Target configuration #
> ########################
> @@ -3277,8 +3280,14 @@ foreach target : target_dirs
> }
> endif
>
> + config_target += keyval.load('configs/targets' / target + '.mak')
> +
> target_kconfig = []
> foreach sym: accelerators
> + # Disallow 64-bit on 32-bit emulation and virtualization
> + if host_long_bits < config_target['TARGET_LONG_BITS'].to_int()
> + continue
> + endif
> if sym == 'CONFIG_TCG' or target in accelerator_targets.get(sym, [])
> config_target += { sym: 'y' }
> config_all_accel += { sym: 'y' }
> @@ -3292,9 +3301,6 @@ foreach target : target_dirs
> error('No accelerator available for target @0@'.format(target))
> endif
>
> - config_target += keyval.load('configs/targets' / target + '.mak')
> - config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper():
> 'y' }
> -
> if 'TARGET_NEED_FDT' in config_target and not fdt.found()
> if default_targets
> warning('Disabling ' + target + ' due to missing libfdt')
> @@ -3307,6 +3313,7 @@ foreach target : target_dirs
> actual_target_dirs += target
>
> # Add default keys
> + config_target += { 'TARGET_' + config_target['TARGET_ARCH'].to_upper():
> 'y' }
> if 'TARGET_BASE_ARCH' not in config_target
> config_target += {'TARGET_BASE_ARCH': config_target['TARGET_ARCH']}
> endif
> --
> 2.43.0
>
>
With regards,
Daniel
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