On 5/9/2025 12:01 PM, Paluri, PavanKumar wrote:
>
>
> On 5/8/2025 5:52 PM, Ashish Kalra wrote:
>> From: Ashish Kalra <ashish.ka...@amd.com>
>>
>> During platform init, SNP initialization may fail for several reasons,
>> such as firmware command failures and incompatible versions. However,
>> the KVM capability may continue to advertise support for it.
>>
>> The platform may have SNP enabled but if SNP_INIT fails then SNP is
>> not supported by KVM.
>>
>> During KVM module initialization query the SNP platform status to obtain
>> the SNP initialization state and use it as an additional condition to
>> determine support for SEV-SNP.
>>
>> Co-developed-by: Sean Christopherson <sea...@google.com>
>> Signed-off-by: Sean Christopherson <sea...@google.com>
>> Co-developed-by: Pratik R. Sampat <prsam...@amd.com>
>> Signed-off-by: Pratik R. Sampat <prsam...@amd.com>
>> Signed-off-by: Ashish Kalra <ashish.ka...@amd.com>
>> ---
>> arch/x86/kvm/svm/sev.c | 43 +++++++++++++++++++++++++++++++++---------
>> 1 file changed, 34 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
>> index ada53f04158c..a6abdb26f877 100644
>> --- a/arch/x86/kvm/svm/sev.c
>> +++ b/arch/x86/kvm/svm/sev.c
>> @@ -2934,6 +2934,32 @@ void __init sev_set_cpu_caps(void)
>> }
>> }
>>
>> +static bool sev_is_snp_initialized(void)
>
> s/sev_is_snp_initialized/is_sev_snp_initalized looks better.
>
Actually the convention is sev_is_xx().
>> +{
>> + struct sev_user_data_snp_status *status;
>> + struct sev_data_snp_addr buf;
>> + bool initialized = false;
>> + void *data;
>> + int error;
>> +
>> + data = snp_alloc_firmware_page(GFP_KERNEL_ACCOUNT | __GFP_ZERO);
>> + if (!data)
>> + return initialized;
>> +
>> + buf.address = __psp_pa(data);
>> + if (sev_do_cmd(SEV_CMD_SNP_PLATFORM_STATUS, &buf, &error))
>> + goto out;
>> +
>> + status = (struct sev_user_data_snp_status *)data;
>> + if (status->state)
>> + initialized = true;
>> +
>> +out:
>> + snp_free_firmware_page(data);
>> +
>> + return initialized;
>> +}
>> +
>> void __init sev_hardware_setup(void)
>> {
>> unsigned int eax, ebx, ecx, edx, sev_asid_count, sev_es_asid_count;
>> @@ -3038,6 +3064,14 @@ void __init sev_hardware_setup(void)
>> sev_snp_supported = sev_snp_enabled &&
>> cc_platform_has(CC_ATTR_HOST_SEV_SNP);
>>
>> out:
>> + if (sev_enabled) {
>> + init_args.probe = true;
>> + if (sev_platform_init(&init_args))
>> + sev_supported = sev_es_supported = sev_snp_supported =
>> false;
>> + else
>> + sev_snp_supported &= sev_is_snp_initialized();
>> + }
>> +
>> if (boot_cpu_has(X86_FEATURE_SEV))
>> pr_info("SEV %s (ASIDs %u - %u)\n",
>> sev_supported ? min_sev_asid <= max_sev_asid ?
>> "enabled" :
>> @@ -3064,15 +3098,6 @@ void __init sev_hardware_setup(void)
>> sev_supported_vmsa_features = 0;
>> if (sev_es_debug_swap_enabled)
>> sev_supported_vmsa_features |= SVM_SEV_FEAT_DEBUG_SWAP;
>
> On what kernel version is this patch based on? I do not see the below
> diff in 6.15-rc5.
>
This is based on linux-next.
Thanks,
Ashish
> Thanks,
> Pavan
>> -
>> - if (!sev_enabled)
>> - return;
>> -
>> - /*
>> - * Do both SNP and SEV initialization at KVM module load.
>> - */
>> - init_args.probe = true;
>> - sev_platform_init(&init_args);
>> }
>>
>> void sev_hardware_unsetup(void)
>
