On Tue, Jul 21, 2009 at 12:47:45PM -0300, Marcelo Tosatti wrote:
> 
> If a migrated vcpu matches the asid_generation value of the target pcpu,
> there will be no TLB flush via TLB_CONTROL_FLUSH_ALL_ASID.
> 
> The check for vcpu.cpu in pre_svm_run is meaningless since svm_vcpu_load 
> already updated it on schedule in.
> 
> Such vcpu will VMRUN with stale TLB entries.
> 
> Based on original patch from Joerg Roedel 
> (http://patchwork.kernel.org/patch/10021/)
> 
> Signed-off-by: Marcelo Tosatti <[email protected]>

Acked-by: Joerg Roedel <[email protected]>

> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 18085d3..90fe88f 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -739,6 +739,7 @@ static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
>               svm->vmcb->control.tsc_offset += delta;
>               vcpu->cpu = cpu;
>               kvm_migrate_timers(vcpu);
> +             svm->asid_generation = 0;
>       }
>  
>       for (i = 0; i < NR_HOST_SAVE_USER_MSRS; i++)
> @@ -1071,7 +1072,6 @@ static void new_asid(struct vcpu_svm *svm, struct 
> svm_cpu_data *svm_data)
>               svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ALL_ASID;
>       }
>  
> -     svm->vcpu.cpu = svm_data->cpu;
>       svm->asid_generation = svm_data->asid_generation;
>       svm->vmcb->control.asid = svm_data->next_asid++;
>  }
> @@ -2320,8 +2320,8 @@ static void pre_svm_run(struct vcpu_svm *svm)
>       struct svm_cpu_data *svm_data = per_cpu(svm_data, cpu);
>  
>       svm->vmcb->control.tlb_ctl = TLB_CONTROL_DO_NOTHING;
> -     if (svm->vcpu.cpu != cpu ||
> -         svm->asid_generation != svm_data->asid_generation)
> +     /* FIXME: handle wraparound of asid_generation */
> +     if (svm->asid_generation != svm_data->asid_generation)
>               new_asid(svm, svm_data);
>  }
>  
> 

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