Re: [PATCH v2] KVM: SEV: Add KVM_SEV_SNP_HV_REPORT_REQ command

From: Tom Lendacky

Date: Fri Dec 05 2025 - 09:28:50 EST


On 12/4/25 07:21, Thomas Courrege wrote:
> On 12/2/25 8:29 PM, Tom Lendacky wrote:
>
>>> +
>>> +e_free_rsp:
>>> + /* contains sensitive data */
>>> + memzero_explicit(report_rsp, PAGE_SIZE);
>> Does it? What is sensitive that needs to be cleared?
>
> Combine with others reports, it could allow to do an inventory of the guests,
> which ones share the same author, measurement, policy...
> It is not needed, but generating a report is not a common operation so
> performance is not an issue here. What do you think is the best to do ?

Can't userspace do that just by generating/requesting reports? If there
are no keys, IVs, secrets, etc. in the memory, I don't see what the
memzero_explicit() is accomplishing. Maybe I'm missing something here and
others may have different advice.

Thanks,
Tom

>
> Regards,
> Thomas