On Thu, 4 Sep 2025 19:55:49 +0800
Bibo Mao <maob...@loongson.cn> wrote:
> On 2025/9/4 下午4:13, Igor Mammedov wrote:
> > On Wed, 3 Sep 2025 10:35:56 +0800
> > Bibo Mao <maob...@loongson.cn> wrote:
> >
> >> With cpu hotplug is implemented on LoongArch virt machine, reset
> >> interface with hot-added CPU should be registered. Otherwise there
> >> will be problem if system reboots after cpu is hot-added.
> >>
> >> Now register reset interface with CPU object is realized and remove
> >> the reset interface with CPU object unrealizd.
> >>
> >> Signed-off-by: Bibo Mao <maob...@loongson.cn>
> >> ---
> >> hw/loongarch/boot.c | 13 -------------
> >> target/loongarch/cpu.c | 4 ++++
> >> 2 files changed, 4 insertions(+), 13 deletions(-)
> >>
> >> diff --git a/hw/loongarch/boot.c b/hw/loongarch/boot.c
> >> index 5799b4c75c..a516415822 100644
> >> --- a/hw/loongarch/boot.c
> >> +++ b/hw/loongarch/boot.c
> >> @@ -350,13 +350,6 @@ static int64_t load_kernel_info(struct
> >> loongarch_boot_info *info)
> >> return kernel_entry;
> >> }
> >>
> >> -static void reset_load_elf(void *opaque)
> >> -{
> >> - LoongArchCPU *cpu = opaque;
> >> -
> >> - cpu_reset(CPU(cpu));
> >> -}
> >> -
> >> static void fw_cfg_add_kernel_info(struct loongarch_boot_info *info,
> >> FWCfgState *fw_cfg)
> >> {
> >> @@ -439,12 +432,6 @@ static void loongarch_direct_kernel_boot(MachineState
> >> *ms,
> >> void loongarch_load_kernel(MachineState *ms, struct loongarch_boot_info
> >> *info)
> >> {
> >> LoongArchVirtMachineState *lvms = LOONGARCH_VIRT_MACHINE(ms);
> >> - int i;
> >> -
> >> - /* register reset function */
> >> - for (i = 0; i < ms->smp.cpus; i++) {
> >> - qemu_register_reset(reset_load_elf,
> >> LOONGARCH_CPU(qemu_get_cpu(i)));
> >> - }
> >>
> >> info->kernel_filename = ms->kernel_filename;
> >> info->kernel_cmdline = ms->kernel_cmdline;
> >> diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
> >> index 3a7621c0ea..9edb8ebc4d 100644
> >> --- a/target/loongarch/cpu.c
> >> +++ b/target/loongarch/cpu.c
> >> @@ -668,6 +668,9 @@ static void loongarch_cpu_realizefn(DeviceState *dev,
> >> Error **errp)
> >>
> >> qemu_init_vcpu(cs);
> >> cpu_reset(cs);
> >> + #ifndef CONFIG_USER_ONLY
> >> + qemu_register_resettable(OBJECT(dev));
> >> + #endif
> >
> > I'd put this in virt_cpu_plug() as last step, which should work both for
> > cold and hotpluged cpus. And drop CONFIG_USER_ONLY while at it.
> With symmetry is the same with qemu_unregister_resettable()
> Symmetrically, to put it in virt_cpu_unplug()?
yep
>
> If there are many boards in future, the boards do not need to care about
> registering cpu reset interface, which is done in CPU object already.
lets worry about more boards when that arrives.
that said, yanking reset pin on CPU is usually the board/firmware
responsibility.
PS:
we have reset registered in realizefn() across QEMU, largely due to historical
reasons.
>
> Regards
> Bibo Mao
> >
> > with that
> > Reviewed-by: Igor Mammedov <imamm...@redhat.com>
> >
> > PS:
> > the rest of the patches are very arch specific so I won't review them.
> >
> >>
> >> lacc->parent_realize(dev, errp);
> >> }
> >> @@ -678,6 +681,7 @@ static void loongarch_cpu_unrealizefn(DeviceState *dev)
> >>
> >> #ifndef CONFIG_USER_ONLY
> >> cpu_remove_sync(CPU(dev));
> >> + qemu_unregister_resettable(OBJECT(dev));
> >> #endif
> >>
> >> lacc->parent_unrealize(dev);
> >
>
