Re: [PATCH 08/10] hw/core/reset: Implement qemu_register_reset via qemu_register_resettable

[Zhao Liu]

On Tue, Feb 20, 2024 at 04:06:20PM +0000, Peter Maydell wrote:
> Date: Tue, 20 Feb 2024 16:06:20 +0000
> From: Peter Maydell <peter.maydell@linaro.org>
> Subject: [PATCH 08/10] hw/core/reset: Implement qemu_register_reset via
>  qemu_register_resettable
> X-Mailer: git-send-email 2.34.1
> 
> Reimplement qemu_register_reset() via qemu_register_resettable().
> 
> We define a new LegacyReset object which implements Resettable and
> defines its reset hold phase method to call a QEMUResetHandler
> function.  When qemu_register_reset() is called, we create a new
> LegacyReset object and add it to the simulation_reset
> ResettableContainer.  When qemu_unregister_reset() is called, we find
> the LegacyReset object in the container and remove it.
> 
> This implementation of qemu_unregister_reset() means we'll end up
> scanning the ResetContainer's list of child objects twice, once
> to find the LegacyReset object, and once in g_ptr_array_remove().
> In theory we could avoid this by having the ResettableContainer
> interface include a resettable_container_remove_with_equal_func()
> that took a callback method so that we could use
> g_ptr_array_find_with_equal_func() and g_ptr_array_remove_index().
> But we don't expect qemu_unregister_reset() to be called frequently
> or in hot paths, and we expect the simulation_reset container to
> usually not have many children.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
> The way that a legacy reset function needs to check the ShutdownCause
> and this doesn't line up with the ResetType is a bit awkward; this
> is an area we should come back and clean up, but I didn't want to
> tackle that in this patchset.
> ---
>  include/sysemu/reset.h |   7 ++-
>  hw/core/reset.c        | 137 +++++++++++++++++++++++++++++++----------
>  2 files changed, 110 insertions(+), 34 deletions(-)
>

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>