Re: [PATCH v6 2/9] KVM: SEV: Disable SEV on platform init failure

Pratik Rajesh Sampat
2025-02-14T18:09:17Z

On 2/11/25 7:58 PM, Sean Christopherson wrote:
> On Mon, Feb 03, 2025, Pratik R. Sampat wrote:
>> If the platform initialization sev_platform_init() fails, SEV cannot be
>> set up and a secure VM cannot be spawned. Therefore, in this case,
>> ensure that KVM does not set up, nor advertise support for SEV, SEV-ES,
>> and SEV-SNP.
>>
>> Suggested-by: Nikunj A Dadhania <nikunj@amd.com>
>> Tested-by: Srikanth Aithal <sraithal@amd.com>
>> Signed-off-by: Pratik R. Sampat <prsampat@amd.com>
>> ---
>> v5..v6:
>>
>> * Rename is_sev_platform_init to sev_fw_initialized (Nikunj)
>> * Collected tags from Srikanth.
>> ---
>> arch/x86/kvm/svm/sev.c | 2 +-
>> drivers/crypto/ccp/sev-dev.c | 10 ++++++++++
>> include/linux/psp-sev.h | 3 +++
>> 3 files changed, 14 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
>> index b709c2f0945c..42d1309f8a54 100644
>> --- a/arch/x86/kvm/svm/sev.c
>> +++ b/arch/x86/kvm/svm/sev.c
>> @@ -2957,7 +2957,7 @@ void __init sev_hardware_setup(void)
>> bool sev_es_supported = false;
>> bool sev_supported = false;
>>
>> - if (!sev_enabled || !npt_enabled || !nrips)
>> + if (!sev_fw_initialized() || !sev_enabled || !npt_enabled || !nrips)
>> goto out;
>
> Me thinks this wasn't tested with KVM_AMD built-in[1]. I'm pretty sure Ashish's
> fix[2] solves all of this?
>
> [1] https://lore.kernel.org/all/d6d08c6b-9602-4f3d-92c2-8db6d50a1b92@amd.com
> [2] https://lore.kernel.org/all/f78ddb64087df27e7bcb1ae0ab53f55aa0804fab.1739226950.git.ashish.kalra@amd.com

Thanks for pointing this out. I hadn't considered this earlier.

The combination of both of these should solve all of the issues caused
by a failing SEV INIT. I will remove this patch for the next iteration
then.

Thanks!