On 8/1/19 7:14 AM, Aaron Lindsay OS via Qemu-devel wrote:
> On Jul 31 17:06, Alex Bennée wrote:
>> We need to keep a local per-cpu copy of the data as other threads may
>> be running. We use a automatically growing array and re-use the space
>> for subsequent queries.
>
> [...]
>
>> +bool tlb_plugin_lookup(CPUState *cpu, target_ulong addr, int mmu_idx,
>> + bool is_store, struct qemu_plugin_hwaddr *data)
>> +{
>> + CPUArchState *env = cpu->env_ptr;
>> + CPUTLBEntry *tlbe = tlb_entry(env, mmu_idx, addr);
>> + target_ulong tlb_addr = is_store ? tlb_addr_write(tlbe) :
>> tlbe->addr_read;
>> +
>> + if (tlb_hit(tlb_addr, addr)) {
>> + if (tlb_addr & TLB_MMIO) {
>> + data->hostaddr = 0;
>> + data->is_io = true;
>> + /* XXX: lookup device */
>> + } else {
>> + data->hostaddr = addr + tlbe->addend;
>> + data->is_io = false;
>> + }
>> + return true;
>> + }
>> + return false;
>> +}
>
> In what cases do you expect tlb_hit() should not evaluate to true here?
> Will returns of false only be in error cases, or do you expect it can
> occur during normal operation? In particular, I'm interested in ensuring
> this is as reliable as possible, since some plugins may require physical
> addresses.
I have the same question. Given the access has just succeeded, it would seem
to be that the tlb entry *must* hit. No victim tlb check or anything.
r~
