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From: "Thomas Courrege" <thomas.courrege@vates.tech>
To: "Tom Lendacky" <thomas.lendacky@amd.com>,
	pbonzini@redhat.com, seanjc@google.com, corbet@lwn.net,
	ashish.kalra@amd.com, john.allen@amd.com,
	herbert@gondor.apana.org.au, nikunj@amd.com
Cc: x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org
Subject: Re: [PATCH v2] KVM: SEV: Add KVM_SEV_SNP_HV_REPORT_REQ command
Date: Fri, 12 Dec 2025 10:19:04 +0000	[thread overview]
Message-ID: <4fa34bbd-ca16-4f19-8822-d72297375c7d@vates.tech> (raw)
In-Reply-To: <7b3c264c-03bb-4dc5-b5c6-24fb0bd179cf@amd.com>


On 12/5/25 3:28 PM, Tom Lendacky wrote:
> 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.
You're right, and there's no warranty the userspace will memzero the report
And the SEV report isn't memzero too

Thanks, 
Thomas


      reply	other threads:[~2025-12-12 10:19 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-01 15:19 [PATCH v2] KVM: SEV: Add KVM_SEV_SNP_HV_REPORT_REQ command Thomas Courrege
2025-12-02 19:28 ` Tom Lendacky
2025-12-04 13:21   ` Thomas Courrege
2025-12-05 14:28     ` Tom Lendacky
2025-12-12 10:19       ` Thomas Courrege [this message]

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