Re: [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with

Avi Kivity
2011-10-31T12:50:40Z

On 10/31/2011 09:53 AM, Alexander Graf wrote:
> From: Scott Wood <scottwood@freescale.com>
>
> Delay allocation of the shadow pid until we're ready to disable
> preemption and write the entry.
>
> @@ -507,21 +507,16 @@ static inline void kvmppc_e500_deliver_tlb_miss(struct kvm_vcpu *vcpu,
> vcpu_e500->mas7 = 0;
> }
>
> +/* TID must be supplied by the caller */
> static inline void kvmppc_e500_setup_stlbe(struct kvmppc_vcpu_e500 *vcpu_e500,
> struct tlbe *gtlbe, int tsize,
> struct tlbe_priv *priv,
> u64 gvaddr, struct tlbe *stlbe)
> {
> pfn_t pfn = priv->pfn;
> - unsigned int stid;
> -
> - stid = kvmppc_e500_get_sid(vcpu_e500, get_tlb_ts(gtlbe),
> - get_tlb_tid(gtlbe),
> - get_cur_pr(&vcpu_e500->vcpu), 0);
>
> /* Force TS=1 IPROT=0 for all guest mappings. */
> - stlbe->mas1 = MAS1_TSIZE(tsize)
> - | MAS1_TID(stid) | MAS1_TS | MAS1_VALID;
> + stlbe->mas1 = MAS1_TSIZE(tsize) | MAS1_TS | MAS1_VALID;
> stlbe->mas2 = (gvaddr & MAS2_EPN)
> | e500_shadow_mas2_attrib(gtlbe->mas2,
> vcpu_e500->vcpu.arch.shared->msr & MSR_PR);
> @@ -816,6 +811,24 @@ int kvmppc_e500_emul_tlbsx(struct kvm_vcpu *vcpu, int rb)
> return EMULATE_DONE;
> }
>
> +/* sesel is index into the set, not the whole array */
> +static void write_stlbe(struct kvmppc_vcpu_e500 *vcpu_e500,
> + struct tlbe *gtlbe,
> + struct tlbe *stlbe,
> + int stlbsel, int sesel)
> +{
> + int stid;
> +
> + preempt_disable();
> + stid = kvmppc_e500_get_sid(vcpu_e500, get_tlb_ts(gtlbe),
> + get_tlb_tid(gtlbe),
> + get_cur_pr(&vcpu_e500->vcpu), 0);
> +
> + stlbe->mas1 |= MAS1_TID(stid);
> + write_host_tlbe(vcpu_e500, stlbsel, sesel, stlbe);
> + preempt_enable();
> +}
> +
>

This naked preempt_disable() is fishy. What happens if we're migrated
immediately afterwards? we fault again and redo?

I realize that the patch doesn't introduce this.

--
error compiling committee.c: too many arguments to function