Re: [PATCH v6] kvm: make vcpu life cycle separated from kvm instance

From: Takuya Yoshikawa
Date: Tue Dec 27 2011 - 06:20:58 EST


(2011/12/27 17:38), Liu Ping Fan wrote:
> From: Liu Ping Fan<pingfank@xxxxxxxxxxxxxxxxxx>
>
> Currently, vcpu can be destructed only when kvm instance destroyed.
> Change this to vcpu's destruction before kvm instance, so vcpu MUST
> and CAN be destroyed before kvm's destroy.

I really don't understand why this big change can be justified by only
3 lines.

>
> Signed-off-by: Liu Ping Fan<pingfank@xxxxxxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/i8254.c | 10 +++--
> arch/x86/kvm/i8259.c | 17 +++++--
> arch/x86/kvm/x86.c | 53 +++++++++++-----------
> include/linux/kvm_host.h | 20 +++-----
> virt/kvm/irq_comm.c | 6 ++-
> virt/kvm/kvm_main.c | 110 +++++++++++++++++++++++++++++++++++-----------
> 6 files changed, 140 insertions(+), 76 deletions(-)
>

You are introducing kvm_arch_vcpu_zap().

Then, apart from the "zap" naming issue I mentioned last time,
what about other architectures than x86?


> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 900c763..b88d418d 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -117,6 +117,7 @@ enum {
>
> struct kvm_vcpu {
> struct kvm *kvm;
> + struct list_head list;
> #ifdef CONFIG_PREEMPT_NOTIFIERS
> struct preempt_notifier preempt_notifier;
> #endif
> @@ -251,12 +252,14 @@ struct kvm {
> struct mm_struct *mm; /* userspace tied to this vm */
> struct kvm_memslots *memslots;
> struct srcu_struct srcu;
> + struct srcu_struct srcu_vcpus;
> +

Another srcu. This alone is worth explaining in the changelog IMO.

Takuya

> #ifdef CONFIG_KVM_APIC_ARCHITECTURE
> u32 bsp_vcpu_id;
> #endif
> - struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
> + struct list_head vcpus;
> atomic_t online_vcpus;
> - int last_boosted_vcpu;
> + int last_boosted_vcpu_id;
> struct list_head vm_list;
> struct mutex lock;
> struct kvm_io_bus *buses[KVM_NR_BUSES];
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