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Re: [Qemu-devel] [PATCH 1/1] cpu: Correct cpu-hotplug failure
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 1/1] cpu: Correct cpu-hotplug failure |
Date: |
Thu, 25 Jul 2013 10:39:54 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 |
Hi,
Am 25.07.2013 08:27, schrieb Chen Fan:
> When useing x86_64-softmmu --enable-kvm boot qemu, cpu-add command fails to
> add a vcpu,
> there show (KVM: setting VAPIC address failed).
>
> The reason is that we use an uninitialized cpu->kvm-fd to ioctl.
> so we move realizing apic to the back of qemu_init_vcpu.
>
> Signed-off-by: Chen Fan <address@hidden>
> ---
> include/qom/cpu.h | 2 ++
> qom/cpu.c | 13 +++++++++++++
> target-i386/cpu.c | 10 ++++------
> 3 files changed, 19 insertions(+), 6 deletions(-)
First, please CC the maintainer - in this case me.
The referenced commit is this one:
http://git.qemu.org/?p=qemu.git;a=commit;h=c643bed99
Sorry for regressing.
> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
> index daf1835..487a808 100644
> --- a/include/qom/cpu.h
> +++ b/include/qom/cpu.h
> @@ -80,6 +80,7 @@ struct TranslationBlock;
> * @synchronize_from_tb: Callback for synchronizing state from a TCG
> * #TranslationBlock.
> * @get_phys_page_debug: Callback for obtaining a physical address.
> + * @apic_realize: Callback for realizing apic.
> * @vmsd: State description for migration.
> *
> * Represents a CPU family or model.
> @@ -108,6 +109,7 @@ typedef struct CPUClass {
> void (*set_pc)(CPUState *cpu, vaddr value);
> void (*synchronize_from_tb)(CPUState *cpu, struct TranslationBlock *tb);
> hwaddr (*get_phys_page_debug)(CPUState *cpu, vaddr addr);
> + void (*apic_realize)(CPUState *cpu, Error **errp);
>
> const struct VMStateDescription *vmsd;
> int (*write_elf64_note)(WriteCoreDumpFunction f, CPUState *cpu,
> diff --git a/qom/cpu.c b/qom/cpu.c
> index 5c45ab5..88c6028 100644
> --- a/qom/cpu.c
> +++ b/qom/cpu.c
> @@ -213,12 +213,25 @@ static ObjectClass *cpu_common_class_by_name(const char
> *cpu_model)
> return NULL;
> }
>
> +static void cpu_apic_realize(CPUState *cpu, Error **errp)
> +{
> + CPUClass *cc = CPU_GET_CLASS(cpu);
> + if (cc->apic_realize != NULL) {
> + (*cc->apic_realize)(cpu, errp);
> + }
> +}
> +
> static void cpu_common_realizefn(DeviceState *dev, Error **errp)
> {
> CPUState *cpu = CPU(dev);
>
> qemu_init_vcpu(cpu);
>
> + cpu_apic_realize(cpu, errp);
> + if (error_is_set(errp)) {
> + return;
> + }
> +
> if (dev->hotplugged) {
> cpu_synchronize_post_init(cpu);
> notifier_list_notify(&cpu_added_notifiers, dev);
This is bogus since APIC is an x86 thing. It should stay in
target-i386/cpu.c. We could generalize it as a post-vCPU-init hook, but
I don't think that's needed here:
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index cd350cb..916d69e 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2311,8 +2311,9 @@ static void x86_cpu_apic_create(X86CPU *cpu, Error
> **errp)
> apic->cpu = cpu;
> }
>
> -static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp)
> +static void x86_cpu_apic_realize(CPUState *s, Error **errp)
> {
> + X86CPU *cpu = X86_CPU(s);
> CPUX86State *env = &cpu->env;
>
> if (env->apic_state == NULL) {
> @@ -2326,7 +2327,7 @@ static void x86_cpu_apic_realize(X86CPU *cpu, Error
> **errp)
> }
> }
> #else
> -static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp)
> +static void x86_cpu_apic_realize(CPUState *s, Error **errp)
> {
> }
> #endif
> @@ -2388,10 +2389,6 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
>
> mce_init(cpu);
>
> - x86_cpu_apic_realize(cpu, &local_err);
> - if (local_err != NULL) {
> - goto out;
> - }
> cpu_reset(CPU(cpu));
>
> xcc->parent_realize(dev, &local_err);
I think all that really needs to happen is to move the above four lines
to below xcc->parent_realize(). I doubt that a hot-add notifier is going
to fiddle with the APIC - we're just incrementing the number of CPUs in
the RTC today.
Can you send a v2 doing so please? Thanks.
Regards,
Andreas
> @@ -2540,6 +2537,7 @@ static void x86_cpu_common_class_init(ObjectClass *oc,
> void *data)
> cc->synchronize_from_tb = x86_cpu_synchronize_from_tb;
> cc->get_arch_id = x86_cpu_get_arch_id;
> cc->get_paging_enabled = x86_cpu_get_paging_enabled;
> + cc->apic_realize = x86_cpu_apic_realize;
> #ifndef CONFIG_USER_ONLY
> cc->get_memory_mapping = x86_cpu_get_memory_mapping;
> cc->get_phys_page_debug = x86_cpu_get_phys_page_debug;
>
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