Alexander Graf <agraf@xxxxxxx> writes: > On 21.01.2014, at 10:42, Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> wrote: > >> Liu Ping Fan <kernelfans@xxxxxxxxx> writes: >> >>> To make sure that on host, the pages marked with _PAGE_NUMA result in a fault >>> when guest access them, we should force the checking when guest uses hypercall >>> to setup hpte. >>> >>> Signed-off-by: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx> >> >> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> >> >> When we mark pte with _PAGE_NUMA we already call mmu_notifier_invalidate_range_start and >> mmu_notifier_invalidate_range_end, which will mark existing guest hpte >> entry as HPTE_V_ABSENT. Now we need to do that when we are inserting new >> guest hpte entries. This patch does that. > > So what happens next? We insert a page into the HTAB without > HPTE_V_VALID set, so the guest will fail to use it. If the guest does > an H_READ on it it will suddenly turn to V_VALID though? As per the guest the entry is valid, so yes an hread should return a valid entry. But in real hpte we would mark it not valid. > > I might need a crash course in the use of HPTE_V_ABSENT. When guest tries to access the address, the host will handle the fault. kvmppc_hpte_hv_fault should give more info -aneesh -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
