Re: [PATCH v2 9/9] crypto: ccp: Move SEV/SNP Platform initialization to KVM

[Alexey Kardashevskiy <aik@amd.com>]

On 17/12/24 11:00, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
> 
> 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.
> 
> Remove the psp_init_on_probe parameter as it not used anymore.
> Remove the probe field from struct sev_platform_init_args as it is
> not used anymore.
> Remove _sev_platform_init_locked() as it not used anymore and to
> support separate SNP and SEV initialization sev_platform_init() is
> now modified to do only SEV initialization and call
> __sev_platform_init_locked() directly.
> 
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
>   drivers/crypto/ccp/sev-dev.c | 55 +-----------------------------------
>   include/linux/psp-sev.h      |  4 ---
>   2 files changed, 1 insertion(+), 58 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index 53c438b2b712..fbae688e4b7d 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -69,10 +69,6 @@ static char *init_ex_path;
>   module_param(init_ex_path, charp, 0444);
>   MODULE_PARM_DESC(init_ex_path, " Path for INIT_EX data; if set try INIT_EX");
>   
> -static bool psp_init_on_probe = true;
> -module_param(psp_init_on_probe, bool, 0444);
> -MODULE_PARM_DESC(psp_init_on_probe, "  if true, the PSP will be initialized on module init. Else the PSP will be initialized on the first command requiring it");
> -
>   MODULE_FIRMWARE("amd/amd_sev_fam17h_model0xh.sbin"); /* 1st gen EPYC */
>   MODULE_FIRMWARE("amd/amd_sev_fam17h_model3xh.sbin"); /* 2nd gen EPYC */
>   MODULE_FIRMWARE("amd/amd_sev_fam19h_model0xh.sbin"); /* 3rd gen EPYC */
> @@ -1329,46 +1325,12 @@ static int __sev_platform_init_locked(int *error)
>   	return rc;
>   }
>   
> -static int _sev_platform_init_locked(struct sev_platform_init_args *args)
> -{
> -	struct sev_device *sev;
> -	int rc;
> -
> -	if (!psp_master || !psp_master->sev_data)
> -		return -ENODEV;
> -
> -	sev = psp_master->sev_data;
> -
> -	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);
> -	}
> -
> -	/* Defer legacy SEV/SEV-ES support if allowed by caller/module. */
> -	if (args->probe && !psp_init_on_probe)
> -		return 0;
> -
> -	return __sev_platform_init_locked(&args->error);
> -}
> -
>   int sev_platform_init(struct sev_platform_init_args *args)
>   {
>   	int rc;
>   
>   	mutex_lock(&sev_cmd_mutex);
> -	rc = _sev_platform_init_locked(args);
> +	rc = __sev_platform_init_locked(&args->error);
>   	mutex_unlock(&sev_cmd_mutex);
>   
>   	return rc;
> @@ -2556,9 +2518,7 @@ 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;
> @@ -2581,16 +2541,6 @@ 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:
> @@ -2605,7 +2555,4 @@ void sev_pci_exit(void)
>   
>   	if (!sev)
>   		return;

Can remove the above 4 lines too. Otherwise

Reviewed-by: Alexey Kardashevskiy <aik@amd.com>


> -
> -	sev_firmware_shutdown(sev);
> -
>   }
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index e50643aef8a9..dec89fc0b356 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -794,13 +794,9 @@ struct sev_data_snp_shutdown_ex {
>    * struct sev_platform_init_args
>    *
>    * @error: SEV firmware error code
> - * @probe: True if this is being called as part of CCP module probe, which
> - *  will defer SEV_INIT/SEV_INIT_EX firmware initialization until needed
> - *  unless psp_init_on_probe module param is set
>    */
>   struct sev_platform_init_args {
>   	int error;
> -	bool probe;
>   };
>   
>   /**

-- 
Alexey