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
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
