Re: [PATCH v4 21/43] arm64: RME: Runtime faulting of memory

[Steven Price]

On 22/08/2024 04:32, Aneesh Kumar K.V wrote:
> Steven Price <steven.price@xxxxxxx> writes:
> 
>> At runtime if the realm guest accesses memory which hasn't yet been
>> mapped then KVM needs to either populate the region or fault the guest.
>>
>> For memory in the lower (protected) region of IPA a fresh page is
>> provided to the RMM which will zero the contents. For memory in the
>> upper (shared) region of IPA, the memory from the memslot is mapped
>> into the realm VM non secure.
>>
>> Signed-off-by: Steven Price <steven.price@xxxxxxx>
>> ---
>> Changes since v2:
>>  * Avoid leaking memory if failing to map it in the realm.
>>  * Correctly mask RTT based on LPA2 flag (see rtt_get_phys()).
>>  * Adapt to changes in previous patches.
>>
> 
> ....
> 
>> -	gfn = ipa >> PAGE_SHIFT;
>> +	gfn = (ipa & ~gpa_stolen_mask) >> PAGE_SHIFT;
>>  	memslot = gfn_to_memslot(vcpu->kvm, gfn);
>> +
>> +	if (kvm_slot_can_be_private(memslot)) {
>> +		ret = private_memslot_fault(vcpu, fault_ipa, memslot);
>> +		if (ret != -EAGAIN)
>> +			goto out;
>> +	}
>>
> 
> Shouldn't this be s/fault_ipa/ipa ?

Well they should both be the same unless we're in some scary parallel
universe where we have nested virtualisation *and* realms at the same
time (shudder!). But yes "ipa" would be more consistent so I'll change it!

Steve

> 	ret = private_memslot_fault(vcpu, ipa, memslot);
> 
> -aneesh