Re: [PATCH v5 03/12] Add async PF initialization to PV guest.

Gleb Natapov
2010-08-23T15:36:50Z

On Mon, Aug 23, 2010 at 06:26:58PM +0300, Avi Kivity wrote:
> On 07/19/2010 06:30 PM, Gleb Natapov wrote:
> >Enable async PF in a guest if async PF capability is discovered.
> >
> >Signed-off-by: Gleb Natapov<gleb@redhat.com>
> >---
> > arch/x86/include/asm/kvm_para.h | 5 +++
> > arch/x86/kernel/kvm.c | 68 +++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 73 insertions(+), 0 deletions(-)
> >
> >diff --git a/arch/x86/include/asm/kvm_para.h b/arch/x86/include/asm/kvm_para.h
> >index 5b05e9f..f1662d7 100644
> >--- a/arch/x86/include/asm/kvm_para.h
> >+++ b/arch/x86/include/asm/kvm_para.h
> >@@ -65,6 +65,11 @@ struct kvm_mmu_op_release_pt {
> > __u64 pt_phys;
> > };
> >
> >+struct kvm_vcpu_pv_apf_data {
> >+ __u32 reason;
> >+ __u32 enabled;
> >+};
> >+
>
> The guest will have to align this on a 64 byte boundary, should this
> be marked __aligned(64) here?
>
I do __aligned(64) when I declare variable of that type:

static DEFINE_PER_CPU(struct kvm_vcpu_pv_apf_data, apf_reason) __aligned(64);

> >@@ -231,12 +235,72 @@ static void __init paravirt_ops_setup(void)
> > #endif
> > }
> >
> >+void __cpuinit kvm_guest_cpu_init(void)
> >+{
> >+ if (!kvm_para_available())
> >+ return;
> >+
> >+ if (kvm_para_has_feature(KVM_FEATURE_ASYNC_PF)) {
> >+ u64 pa = __pa(&__get_cpu_var(apf_reason));
> >+
> >+ if (native_write_msr_safe(MSR_KVM_ASYNC_PF_EN,
> >+ pa | KVM_ASYNC_PF_ENABLED, pa>> 32))
> >+ return;
> >+ __get_cpu_var(apf_reason).enabled = 1;
> >+ printk(KERN_INFO"KVM setup async PF for cpu %d\n",
> >+ smp_processor_id());
> >+ }
> >+}
>
> Need a way to disable apf from the guest kernel command line.
>
OK.

> >+
> >+static int __cpuinit kvm_cpu_notify(struct notifier_block *self,
> >+ unsigned long action, void *hcpu)
> >+{
> >+ switch (action) {
> >+ case CPU_ONLINE:
> >+ case CPU_ONLINE_FROZEN:
> >+ kvm_guest_cpu_init();
> >+ break;
> >+ default:
> >+ break;
>
> Should we disable apf if the cpu is dying here?
>
Why? Can CPU die with outstanding sleeping tasks?

> >+ }
> >+ return NOTIFY_OK;
> >+}
> >+
>
> --
> error compiling committee.c: too many arguments to function

--
Gleb.