Hi Alex,
> From: Alex Bennée <alex.ben...@linaro.org>
> Sent: Friday, August 16, 2024 4:37 PM
> To: Salil Mehta <salil.me...@huawei.com>
>
> Salil Mehta <salil.me...@huawei.com> writes:
>
> > vCPU Hot-unplug will result in QOM CPU object unrealization which will
> > do away with all the vCPU thread creations, allocations, registrations
> > that happened as part of the realization process. This change
> > introduces the ARM CPU unrealize function taking care of exactly that.
> >
> > Note, initialized KVM vCPUs are not destroyed in host KVM but their
> > Qemu context is parked at the QEMU KVM layer.
> >
> > Co-developed-by: Keqian Zhu <zhukeqi...@huawei.com>
> > Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com>
> > Signed-off-by: Salil Mehta <salil.me...@huawei.com>
> > Reported-by: Vishnu Pajjuri <vis...@os.amperecomputing.com>
> > [VP: Identified CPU stall issue & suggested probable fix]
> > Signed-off-by: Salil Mehta <salil.me...@huawei.com>
> > ---
> > target/arm/cpu.c | 101
> +++++++++++++++++++++++++++++++++++++++++
> > target/arm/cpu.h | 14 ++++++
> > target/arm/gdbstub.c | 6 +++
> > target/arm/helper.c | 25 ++++++++++
> > target/arm/internals.h | 3 ++
> > target/arm/kvm.c | 5 ++
> > 6 files changed, 154 insertions(+)
> >
> > diff --git a/target/arm/cpu.c b/target/arm/cpu.c index
> > c92162fa97..a3dc669309 100644
> > --- a/target/arm/cpu.c
> > +++ b/target/arm/cpu.c
> > @@ -157,6 +157,16 @@ void
> arm_register_pre_el_change_hook(ARMCPU *cpu, ARMELChangeHookFn
> *hook,
> > QLIST_INSERT_HEAD(&cpu->pre_el_change_hooks, entry, node); }
> >
> > +void arm_unregister_pre_el_change_hooks(ARMCPU *cpu) {
> > + ARMELChangeHook *entry, *next;
> > +
> > + QLIST_FOREACH_SAFE(entry, &cpu->pre_el_change_hooks, node,
> next) {
> > + QLIST_REMOVE(entry, node);
> > + g_free(entry);
> > + }
> > +}
> > +
> > void arm_register_el_change_hook(ARMCPU *cpu,
> ARMELChangeHookFn *hook,
> > void *opaque) { @@ -168,6 +178,16
> > @@ void arm_register_el_change_hook(ARMCPU *cpu,
> ARMELChangeHookFn *hook,
> > QLIST_INSERT_HEAD(&cpu->el_change_hooks, entry, node); }
> >
> > +void arm_unregister_el_change_hooks(ARMCPU *cpu) {
> > + ARMELChangeHook *entry, *next;
> > +
> > + QLIST_FOREACH_SAFE(entry, &cpu->el_change_hooks, node, next) {
> > + QLIST_REMOVE(entry, node);
> > + g_free(entry);
> > + }
> > +}
> > +
> > static void cp_reg_reset(gpointer key, gpointer value, gpointer
> > opaque) {
> > /* Reset a single ARMCPRegInfo register */ @@ -2552,6 +2572,85 @@
> > static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
> > acc->parent_realize(dev, errp);
> > }
> >
> > +static void arm_cpu_unrealizefn(DeviceState *dev) {
> > + ARMCPUClass *acc = ARM_CPU_GET_CLASS(dev);
> > + ARMCPU *cpu = ARM_CPU(dev);
> > + CPUARMState *env = &cpu->env;
> > + CPUState *cs = CPU(dev);
> > + bool has_secure;
> > +
> > + has_secure = cpu->has_el3 || arm_feature(env,
> > + ARM_FEATURE_M_SECURITY);
> > +
> > + /* rock 'n' un-roll, whatever happened in the arm_cpu_realizefn
> cleanly */
> > + cpu_address_space_destroy(cs, ARMASIdx_NS);
>
> On current master this will fail:
>
> ../../target/arm/cpu.c: In function ‘arm_cpu_unrealizefn’:
> ../../target/arm/cpu.c:2626:5: error: implicit declaration of function
> ‘cpu_address_space_destroy’ [-Werror=implicit-function-declaration]
> 2626 | cpu_address_space_destroy(cs, ARMASIdx_NS);
> | ^~~~~~~~~~~~~~~~~~~~~~~~~
> ../../target/arm/cpu.c:2626:5: error: nested extern declaration of
> ‘cpu_address_space_destroy’ [-Werror=nested-externs]
> cc1: all warnings being treated as errors
The current master already has arch-agnostic patch-set. I've applied the
RFC V3 to the latest and complied. I did not see this issue?
I've create a new branch for your reference.
https://github.com/salil-mehta/qemu/tree/virt-cpuhp-armv8/rfc-v4-rc4
Please let me know if this works for you?
Thanks
Salil.
>
> --
> Alex Bennée
> Virtualisation Tech Lead @ Linaro
