linux-kernel - Re: [PATCH v2 0/9] Move initializing SEV/SNP functionality to KVM

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Message-ID: <cc27bfe2-de7c-4038-86e3-58da65f84e50@amd.com>
Date: Tue, 17 Dec 2024 15:16:44 -0600
From: "Kalra, Ashish" <ashish.kalra@....com>
To: Dionna Amalie Glaze <dionnaglaze@...gle.com>
Cc: seanjc@...gle.com, pbonzini@...hat.com, tglx@...utronix.de,
 mingo@...hat.com, bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
 hpa@...or.com, thomas.lendacky@....com, john.allen@....com,
 herbert@...dor.apana.org.au, davem@...emloft.net, michael.roth@....com,
 kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-crypto@...r.kernel.org, linux-coco@...ts.linux.dev
Subject: Re: [PATCH v2 0/9] Move initializing SEV/SNP functionality to KVM



On 12/17/2024 10:00 AM, Dionna Amalie Glaze wrote:
> On Mon, Dec 16, 2024 at 3:57 PM Ashish Kalra <Ashish.Kalra@....com> wrote:
>>
>> From: Ashish Kalra <ashish.kalra@....com>
> 
>> The on-demand SEV initialization support requires a fix in QEMU to
>> remove check for SEV initialization to be done prior to launching
>> SEV/SEV-ES VMs.
>> NOTE: With the above fix for QEMU, older QEMU versions will be broken
>> with respect to launching SEV/SEV-ES VMs with the newer kernel/KVM as
>> older QEMU versions require SEV initialization to be done before
>> launching SEV/SEV-ES VMs.
>>
> 
> I don't think this is okay. I think you need to introduce a KVM
> capability to switch over to the new way of initializing SEV VMs and
> deprecate the old way so it doesn't need to be supported for any new
> additions to the interface.
> 

But that means KVM will need to support both mechanisms of doing SEV initialization - during KVM module load time 
and the deferred/lazy (on-demand) SEV INIT during VM launch.

Thanks,
Ashish