Subject: Re: [PATCH] KVM: PPC: e500mc: Relax tlb invalidation condition on vcpu schedule

From: Alexander Graf <[email-masked]>
Date: Thu, 12 Jun 2014 19:04:40 +0200

On 06/12/2014 04:00 PM, Mihai Caraman wrote:
> On vcpu schedule, the condition checked for tlb pollution is too tight.
> The tlb entries of one vcpu are polluted when a different vcpu from the
> same partition runs in-between. Relax the current tlb invalidation
> condition taking into account the lpid.
>
> Signed-off-by: Mihai Caraman <mihai.caraman <at> freescale.com>

Your mailer is broken? :)
This really should be an @.

I think this should work. Scott, please ack.

Alex

> Cc: Scott Wood <scottwood <at> freescale.com>
> ---
>   arch/powerpc/kvm/e500mc.c | 20 +++++++++++++++++---
>   1 file changed, 17 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/kvm/e500mc.c b/arch/powerpc/kvm/e500mc.c
> index 17e4562..2e0cd69 100644
> --- a/arch/powerpc/kvm/e500mc.c
> +++ b/arch/powerpc/kvm/e500mc.c
> @@ -111,10 +111,12 @@ void kvmppc_mmu_msr_notify(struct kvm_vcpu *vcpu, u32 old_msr)
>   }
>   
>   static DEFINE_PER_CPU(struct kvm_vcpu *, last_vcpu_on_cpu);
> +static DEFINE_PER_CPU(int, last_lpid_on_cpu);
>   
>   static void kvmppc_core_vcpu_load_e500mc(struct kvm_vcpu *vcpu, int cpu)
>   {
>   	struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
> +	bool update_last = false, inval_tlb = false;
>   
>   	kvmppc_booke_vcpu_load(vcpu, cpu);
>   
> @@ -140,12 +142,24 @@ static void kvmppc_core_vcpu_load_e500mc(struct kvm_vcpu *vcpu, int cpu)
>   	mtspr(SPRN_GDEAR, vcpu->arch.shared->dar);
>   	mtspr(SPRN_GESR, vcpu->arch.shared->esr);
>   
> -	if (vcpu->arch.oldpir != mfspr(SPRN_PIR) ||
> -	    __get_cpu_var(last_vcpu_on_cpu) != vcpu) {
> -		kvmppc_e500_tlbil_all(vcpu_e500);
> +	if (vcpu->arch.oldpir != mfspr(SPRN_PIR)) {
> +		/* tlb entries deprecated */
> +		inval_tlb = update_last = true;
> +	} else if (__get_cpu_var(last_vcpu_on_cpu) != vcpu) {
> +		update_last = true;
> +		/* tlb entries polluted */
> +		inval_tlb = __get_cpu_var(last_lpid_on_cpu) ==
> +			    vcpu->kvm->arch.lpid;
> +	}
> +
> +	if (update_last) {
>   		__get_cpu_var(last_vcpu_on_cpu) = vcpu;
> +		__get_cpu_var(last_lpid_on_cpu) = vcpu->kvm->arch.lpid;
>   	}
>   
> +	if (inval_tlb)
> +		kvmppc_e500_tlbil_all(vcpu_e500);
> +
>   	kvmppc_load_guest_fp(vcpu);
>   }
>