[PULL 059/153] rust/hpet: Explicitly initialize complex fields in init()

Paolo Bonzini posted 153 patches 1 week, 4 days ago
Maintainers: "Alex Bennée" <alex.bennee@linaro.org>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Thomas Huth <thuth@redhat.com>, Yonggang Luo <luoyonggang@gmail.com>, Richard Henderson <richard.henderson@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Cameron Esfahani <dirty@apple.com>, Roman Bolshakov <rbolshakov@ddn.com>, Phil Dennis-Jordan <phil@philjordan.eu>, Mads Ynddal <mads@ynddal.dk>, Magnus Kulke <magnus.kulke@linux.microsoft.com>, Wei Liu <wei.liu@kernel.org>, Stefano Stabellini <sstabellini@kernel.org>, Anthony PERARD <anthony@xenproject.org>, Paul Durrant <paul@xen.org>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>, David Hildenbrand <david@kernel.org>, Igor Mammedov <imammedo@redhat.com>, Alistair Francis <alistair.francis@wdc.com>, Stefan Berger <stefanb@linux.vnet.ibm.com>, John Snow <jsnow@redhat.com>, Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <fam@euphon.net>, Aarushi Mehta <mehta.aaru20@gmail.com>, Julia Suvorova <jusual@redhat.com>, Stefano Garzarella <sgarzare@redhat.com>, Stefan Weil <sw@weilnetz.de>, Samuel Thibault <samuel.thibault@ens-lyon.org>, "Marc-André Lureau" <marcandre.lureau@redhat.com>, Zhao Liu <zhao1.liu@intel.com>, Peter Maydell <peter.maydell@linaro.org>, Mauro Carvalho Chehab <mchehab+huawei@kernel.org>, "Daniel P. Berrangé" <berrange@redhat.com>, Luc Michel <luc@lmichel.fr>, Damien Hedde <damien.hedde@dahe.fr>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Markus Armbruster <armbru@redhat.com>, Eduardo Habkost <eduardo@habkost.net>, Ani Sinha <anisinha@redhat.com>, Christian Schoenebeck <qemu_oss@crudebyte.com>, Greg Kurz <groug@kaod.org>, "Michael S. Tsirkin" <mst@redhat.com>, Dongjiu Geng <gengdongjiu1@gmail.com>, Aurelien Jarno <aurelien@aurel32.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Cédric Le Goater" <clg@kaod.org>, Steven Lee <steven_lee@aspeedtech.com>, Troy Lee <leetroy@gmail.com>, Jamin Lin <jamin_lin@aspeedtech.com>, Andrew Jeffery <andrew@codeconstruct.com.au>, Joel Stanley <joel@jms.id.au>, Tyrone Ting <kfting@nuvoton.com>, Hao Wu <wuhaotsh@google.com>, Beniamino Galvani <b.galvani@gmail.com>, Strahinja Jankovic <strahinja.p.jankovic@gmail.com>, Niek Linnenbank <nieklinnenbank@gmail.com>, Samuel Tardieu <sam@rfc1149.net>, Antony Pavlov <antonynpavlov@gmail.com>, Igor Mitsyanko <i.mitsyanko@gmail.com>, Jean-Christophe Dubois <jcd@tribudubois.net>, Andrey Smirnov <andrew.smirnov@gmail.com>, Bernhard Beschow <shentey@gmail.com>, Rob Herring <robh@kernel.org>, Subbaraya Sundeep <sundeep.lkml@gmail.com>, Jan Kiszka <jan.kiszka@web.de>, Felipe Balbi <balbi@kernel.org>, Radoslaw Biernacki <rad@semihalf.com>, Leif Lindholm <leif.lindholm@oss.qualcomm.com>, Eric Auger <eric.auger@redhat.com>, Alexandre Iooss <erdnaxe@crans.org>, Shannon Zhao <shannon.zhaosl@gmail.com>, Gerd Hoffmann <kraxel@redhat.com>, Laurent Vivier <laurent@vivier.eu>, Michael Rolnik <mrolnik@gmail.com>, Raphael Norwitz <raphael@enfabrica.net>, Helge Deller <deller@gmx.de>, "Clément Chigot" <chigot@adacore.com>, Frederic Konrad <konrad.frederic@yahoo.fr>, Alberto Garcia <berto@igalia.com>, Yoshinori Sato <yoshinori.sato@nifty.com>, Magnus Damm <magnus.damm@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Halil Pasic <pasic@linux.ibm.com>, Christian Borntraeger <borntraeger@linux.ibm.com>, Jason Herne <jjherne@linux.ibm.com>, Vijai Kumar K <vijai@behindbytes.com>, Nicholas Piggin <npiggin@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, "Collin L. Walling" <walling@linux.ibm.com>, Amit Shah <amit@kernel.org>, Yanan Wang <wangyanan55@huawei.com>, Riku Voipio <riku.voipio@iki.fi>, Paul Burton <paulburton@kernel.org>, Aleksandar Rikalo <arikalo@gmail.com>, Jonathan Cameron <jonathan.cameron@huawei.com>, Fan Ni <fan.ni@samsung.com>, Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>, "Hervé Poussineau" <hpoussin@reactos.org>, BALATON Zoltan <balaton@eik.bme.hu>, Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>, Dmitry Osipenko <dmitry.osipenko@collabora.com>, Dmitry Fleytman <dmitry.fleytman@gmail.com>, Ninad Palsule <ninad@linux.ibm.com>, Glenn Miles <milesg@linux.ibm.com>, "Maciej S. Szmigiero" <maciej.szmigiero@oracle.com>, Corey Minyard <cminyard@mvista.com>, Patrick Leis <venture@google.com>, Alejandro Jimenez <alejandro.j.jimenez@oracle.com>, Sairaj Kodilkar <sarunkod@amd.com>, Jason Wang <jasowang@redhat.com>, Yi Liu <yi.l.liu@intel.com>, "Clément Mathieu--Drif" <clement.mathieu--drif@eviden.com>, David Woodhouse <dwmw2@infradead.org>, Sergio Lopez <slp@redhat.com>, Alexander Graf <graf@amazon.com>, Dorjoy Chowdhury <dorjoychy111@gmail.com>, Song Gao <gaosong@loongson.cn>, Bibo Mao <maobibo@loongson.cn>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Huacai Chen <chenhuacai@kernel.org>, Jia Liu <proljc@gmail.com>, Gautam Menghani <gautam@linux.ibm.com>, Aditya Gupta <adityag@linux.ibm.com>, Xiao Guangrong <xiaoguangrong.eric@gmail.com>, Alexander Bulekov <alxndr@bu.edu>, Bandan Das <bsd@redhat.com>, Darren Kenny <darren.kenny@oracle.com>, Qiuhao Li <Qiuhao.Li@outlook.com>, Artyom Tarasenko <atar4qemu@gmail.com>, Gustavo Romero <gustavo.romero@linaro.org>, Francisco Iglesias <francisco.iglesias@amd.com>, Pavel Pisa <pisa@cmp.felk.cvut.cz>, Vikram Garhwal <vikram.garhwal@bytedance.com>, Sriram Yagnaraman <sriram.yagnaraman@ericsson.com>, Max Filippov <jcmvbkbc@gmail.com>, Jiri Pirko <jiri@resnulli.us>, Sven Schnelle <svens@stackframe.org>, Stafford Horne <shorne@gmail.com>, Elena Ufimtseva <elena.ufimtseva@oracle.com>, Jagannathan Raman <jag.raman@oracle.com>, Chinmay Rath <rathc@linux.ibm.com>, Sai Pavan Boddu <sai.pavan.boddu@amd.com>, Ran Wang <wangran@bosc.ac.cn>, Anup Patel <anup.patel@wdc.com>, Eric Farman <farman@linux.ibm.com>, Matthew Rosato <mjrosato@linux.ibm.com>, Ilya Leoshkevich <iii@linux.ibm.com>, Tony Krowiak <akrowiak@linux.ibm.com>, Farhan Ali <alifm@linux.ibm.com>, Nina Schoetterl-Glausch <nsg@linux.ibm.com>, Jared Rossi <jrossi@linux.ibm.com>, Zhuoying Cai <zycai@linux.ibm.com>, Cornelia Huck <cohuck@redhat.com>, Hannes Reinecke <hare@suse.com>, Bin Meng <bmeng.cn@gmail.com>, Titus Rwantare <titusr@google.com>, Bastian Koppelmann <kbastian@mail.uni-paderborn.de>, Jeuk Kim <jeuk20.kim@samsung.com>, "Hongren (Zenithal) Zheng" <i@zenithal.me>, "Canokeys.org" <contact@canokeys.org>, John Levon <john.levon@nutanix.com>, Thanos Makatos <thanos.makatos@nutanix.com>, Alex Williamson <alex@shazbot.org>, Tomita Moeko <tomitamoeko@gmail.com>, Viresh Kumar <viresh.kumar@linaro.org>, Mathieu Poirier <mathieu.poirier@linaro.org>, Manos Pitsidianakis <manos.pitsidianakis@linaro.org>, "Gonglei (Arei)" <arei.gonglei@huawei.com>, Eric Blake <eblake@redhat.com>, Keith Busch <kbusch@kernel.org>, Klaus Jensen <its@irrelevant.dk>, Jesper Devantier <foss@defmacro.it>, Huai-Cheng Kuo <hchkuo@avery-design.com.tw>, Chris Browy <cbrowy@avery-design.com>, Zhenzhong Duan <zhenzhong.duan@intel.com>, "Dr. David Alan Gilbert" <dave@treblig.org>, Zhang Chen <zhangckid@gmail.com>, Li Zhijian <lizhijian@fujitsu.com>, Mahmoud Mandour <ma.mandourr@gmail.com>, Pierrick Bouvier <pierrick.bouvier@linaro.org>, Cleber Rosa <crosa@redhat.com>, Michael Roth <michael.roth@amd.com>, Maksim Davydov <davydov-max@yandex-team.ru>, David Gibson <david@gibson.dropbear.id.au>, Hyman Huang <yong.huang@smartx.com>, Brian Cain <brian.cain@oss.qualcomm.com>, Marcelo Tosatti <mtosatti@redhat.com>, Pedro Barbuda <pbarbuda@microsoft.com>, Mohamed Mediouni <mohamed@unpredictable.fr>, Coiby Xu <Coiby.Xu@gmail.com>
[PULL 059/153] rust/hpet: Explicitly initialize complex fields in init()
Posted by Paolo Bonzini 1 week, 4 days ago
From: Zhao Liu <zhao1.liu@intel.com>

Explicitly initialize more fields which are complex structures.

For simple types (bool/u32/usize), they can be omitted since C has
already initialized memory to all zeros and this is the valid
initialization for those simple types.

Previously such complex fields (InterruptSource/BqlCell/BqlRefCell) were
not explicitly initialized in init() and it's fine, because simply
setting all memory to zero aligns with their default initialization
behavior. However, this behavior is not robust. When adding new complex
struct or modifying the initial values of existing structs, this default
behavior can easily be broken.

Thus, do explicit initialization for HPET to become a good example.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20251113051937.4017675-16-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/hw/timer/hpet/src/device.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs
index abbaebc405e..d622a6920a8 100644
--- a/rust/hw/timer/hpet/src/device.rs
+++ b/rust/hw/timer/hpet/src/device.rs
@@ -733,6 +733,18 @@ unsafe fn init(mut this: ParentInit<Self>) {
             HPET_REG_SPACE_LEN,
         );
 
+        // Only consider members with more complex structures. C has already
+        // initialized memory to all zeros - simple types (bool/u32/usize) can
+        // rely on this without explicit initialization.
+        uninit_field_mut!(*this, regs).write(Default::default());
+        uninit_field_mut!(*this, hpet_offset).write(Default::default());
+        // Set null_mut for now and post_init() will fill it.
+        uninit_field_mut!(*this, irqs).write(Default::default());
+        uninit_field_mut!(*this, rtc_irq_level).write(Default::default());
+        uninit_field_mut!(*this, pit_enabled).write(Default::default());
+        uninit_field_mut!(*this, num_timers_save).write(Default::default());
+        uninit_field_mut!(*this, hpet_id).write(Default::default());
+
         Self::init_timers(&mut this);
     }
 
-- 
2.52.0