Re: [PATCH v2] target/i386: Add unaccepted memory configuration

[Tom Lendacky <thomas.lendacky@amd.com>]

On 6/30/22 03:14, Daniel P. Berrangé wrote:
> On Wed, Jun 29, 2022 at 07:37:01PM +0000, Dionna Glaze wrote:
>> For SEV-SNP, an OS is "SEV-SNP capable" without supporting this UEFI
>> v2.9 memory type. In order for OVMF to be able to avoid pre-validating
>> potentially hundreds of gibibytes of data before booting, it needs to
>> know if the guest OS can support its use of the new type of memory in
>> the memory map.
> 
> This talks about something supported for SEV-SNP, but....
> 
>>   static void
>>   sev_guest_class_init(ObjectClass *oc, void *data)
>>   {
>> @@ -376,6 +401,14 @@ sev_guest_class_init(ObjectClass *oc, void *data)
>>                                      sev_guest_set_kernel_hashes);
>>       object_class_property_set_description(oc, "kernel-hashes",
>>               "add kernel hashes to guest firmware for measured Linux boot");
>> +    object_class_property_add_enum(oc, "accept-all-memory",
>> +                                   "MemoryAcceptance",
>> +                                   &memory_acceptance_lookup,
>> +        sev_guest_get_accept_all_memory, sev_guest_set_accept_all_memory);
>> +    object_class_property_set_description(
>> +        oc, "accept-all-memory",
>> +        "false: Accept all memory, true: Accept up to 4G and leave the rest unaccepted (UEFI"
>> +        " v2.9 memory type), default: default firmware behavior.");
>>   }
> 
> ..this is adding a property to the 'sev-guest' object, which only
> targets SEV/SEV-ES currently AFAIK.
> 
> The most recent patches I recall for SEV-SNP introduced a new
> 'sev-snp-guest' object instead of overloading the existing
> 'sev-guest' object:
> 
>    https://lists.gnu.org/archive/html/qemu-devel/2021-08/msg04757.html
> 

Correct, the SNP support for Qemu is only RFC at this point until the KVM 
support for SNP is (near) finalized.

Thanks,
Tom

> 
> 
> With regards,
> Daniel