On 2/20/25 14:23, Kalra, Ashish wrote:
> Hello Tom,
>
> On 2/20/2025 2:03 PM, Tom Lendacky wrote:
>> On 2/19/25 14:55, Ashish Kalra wrote:
>>> From: Ashish Kalra <ashish.kalra@xxxxxxx>
>>>
>>> SNP initialization is forced during PSP driver probe purely because SNP
>>> can't be initialized if VMs are running. But the only in-tree user of
>>> SEV/SNP functionality is KVM, and KVM depends on PSP driver for the same.
>>> Forcing SEV/SNP initialization because a hypervisor could be running
>>> legacy non-confidential VMs make no sense.
>>>
>>> This patch removes SEV/SNP initialization from the PSP driver probe
>>> time and moves the requirement to initialize SEV/SNP functionality
>>> to KVM if it wants to use SEV/SNP.
>>>
>>> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>>> Reviewed-by: Alexey Kardashevskiy <aik@xxxxxxx>
>>> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
>>> ---
>>> drivers/crypto/ccp/sev-dev.c | 25 +------------------------
>>> 1 file changed, 1 insertion(+), 24 deletions(-)
>>>
>>> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
>>> index f0f3e6d29200..99a663dbc2b6 100644
>>> --- a/drivers/crypto/ccp/sev-dev.c
>>> +++ b/drivers/crypto/ccp/sev-dev.c
>>> @@ -1346,18 +1346,13 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
>>> if (sev->state == SEV_STATE_INIT)
>>> return 0;
>>>
>>> - /*
>>> - * Legacy guests cannot be running while SNP_INIT(_EX) is executing,
>>> - * so perform SEV-SNP initialization at probe time.
>>> - */
>>> rc = __sev_snp_init_locked(&args->error);
>>> if (rc && rc != -ENODEV) {
>>> /*
>>> * Don't abort the probe if SNP INIT failed,
>>> * continue to initialize the legacy SEV firmware.
>>> */
>>> - dev_err(sev->dev, "SEV-SNP: failed to INIT rc %d, error %#x\n",
>>> - rc, args->error);
>>> + dev_err(sev->dev, "SEV-SNP: failed to INIT, continue SEV INIT\n");
>>
>> Please don't remove the error information.
>>
>
> The error(s) are already being printed in __sev_snp_init_locked() otherwise the same
> error will be printed twice, hence removing it here.
Sounds like this change should be in patch #1 then.
Thanks,
Tom
>
>>> }
>>>
>>> /* Defer legacy SEV/SEV-ES support if allowed by caller/module. */
>>> @@ -2505,9 +2500,7 @@ EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
>>> void sev_pci_init(void)
>>> {
>>> struct sev_device *sev = psp_master->sev_data;
>>> - struct sev_platform_init_args args = {0};
>>> u8 api_major, api_minor, build;
>>> - int rc;
>>>
>>> if (!sev)
>>> return;
>>> @@ -2530,16 +2523,6 @@ void sev_pci_init(void)
>>> api_major, api_minor, build,
>>> sev->api_major, sev->api_minor, sev->build);
>>>
>>> - /* Initialize the platform */
>>> - args.probe = true;
>>> - rc = sev_platform_init(&args);
>>> - if (rc)
>>> - dev_err(sev->dev, "SEV: failed to INIT error %#x, rc %d\n",
>>> - args.error, rc);
>>> -
>>> - dev_info(sev->dev, "SEV%s API:%d.%d build:%d\n", sev->snp_initialized ?
>>> - "-SNP" : "", sev->api_major, sev->api_minor, sev->build);
>>> -
>>> return;
>>>
>>> err:
>>> @@ -2550,10 +2533,4 @@ void sev_pci_init(void)
>>>
>>> void sev_pci_exit(void)
>>> {
>>> - struct sev_device *sev = psp_master->sev_data;
>>> -
>>> - if (!sev)
>>> - return;
>>> -
>>> - sev_firmware_shutdown(sev);
>>
>> Should this remain? If there's a bug in KVM that somehow skips the
>> shutdown call, then SEV will remain initialized. I think the path is
>> safe to call a second time.
>
> Ok.
>
> Thanks,
> Ashish
>
