linux-kernel - Re: [PATCH 2/4] crypto: ccp: Add external API interface for PSP module initialization

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Message-ID: <a65c1d6b-63eb-064f-b947-aa09e5580c05@amd.com>
Date: Wed, 22 Jan 2025 09:53:14 -0600
From: Tom Lendacky <thomas.lendacky@....com>
To: Ashish Kalra <Ashish.Kalra@....com>, 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,
 john.allen@....com, herbert@...dor.apana.org.au, davem@...emloft.net,
 joro@...tes.org, suravee.suthikulpanit@....com, will@...nel.org,
 robin.murphy@....com
Cc: michael.roth@....com, dionnaglaze@...gle.com, vasant.hegde@....com,
 kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-crypto@...r.kernel.org, linux-coco@...ts.linux.dev,
 iommu@...ts.linux.dev
Subject: Re: [PATCH 2/4] crypto: ccp: Add external API interface for PSP
 module initialization

On 1/21/25 19:00, Ashish Kalra wrote:
> From: Sean Christopherson <seanjc@...gle.com>
> 
> Add a new external API interface for PSP module initialization which
> allows PSP SEV driver to be initialized explicitly before proceeding
> with SEV/SNP initialization with KVM if KVM is built-in as the
> dependency between modules is not supported/handled by the initcall
> infrastructure and the dependent PSP module is not implicitly loaded
> before KVM module if KVM module is built-in.

This is big run on sentence. Please start off describing the issue and
why this fixes it.

> 
> Co-developed-by: Ashish Kalra <ashish.kalra@....com>
> Signed-off-by: Ashish Kalra <ashish.kalra@....com>

Your SOB should come after Sean's.

> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  drivers/crypto/ccp/sp-dev.c | 12 ++++++++++++
>  drivers/crypto/ccp/sp-dev.h |  1 +
>  include/linux/psp-sev.h     | 11 +++++++++++
>  3 files changed, 24 insertions(+)
> 
> diff --git a/drivers/crypto/ccp/sp-dev.c b/drivers/crypto/ccp/sp-dev.c
> index 7eb3e4668286..a0cdc03984cb 100644
> --- a/drivers/crypto/ccp/sp-dev.c
> +++ b/drivers/crypto/ccp/sp-dev.c
> @@ -253,8 +253,12 @@ struct sp_device *sp_get_psp_master_device(void)
>  static int __init sp_mod_init(void)
>  {
>  #ifdef CONFIG_X86
> +	static bool initialized;

This definition is within CONFIG_X86, but...

>  	int ret;
>  
> +	if (initialized)
> +		return 0;
> +
>  	ret = sp_pci_init();
>  	if (ret)
>  		return ret;
> @@ -263,6 +267,7 @@ static int __init sp_mod_init(void)
>  	psp_pci_init();
>  #endif
>  
> +	initialized = true;

Add a blank line.

>  	return 0;
>  #endif
>  
> @@ -279,6 +284,13 @@ static int __init sp_mod_init(void)
>  	return -ENODEV;
>  }
>  
> +#if IS_BUILTIN(CONFIG_KVM_AMD) && IS_ENABLED(CONFIG_KVM_AMD_SEV)
> +int __init sev_module_init(void)
> +{
> +	return sp_mod_init();
> +}
> +#endif
> +
>  static void __exit sp_mod_exit(void)
>  {
>  #ifdef CONFIG_X86
> diff --git a/drivers/crypto/ccp/sp-dev.h b/drivers/crypto/ccp/sp-dev.h
> index 6f9d7063257d..3f5f7491bec1 100644
> --- a/drivers/crypto/ccp/sp-dev.h
> +++ b/drivers/crypto/ccp/sp-dev.h
> @@ -148,6 +148,7 @@ int sp_request_psp_irq(struct sp_device *sp, irq_handler_t handler,
>  		       const char *name, void *data);
>  void sp_free_psp_irq(struct sp_device *sp, void *data);
>  struct sp_device *sp_get_psp_master_device(void);
> +int __init sev_module_init(void);

Why is this declared both here and below? Please just have it one place.

>  
>  #ifdef CONFIG_CRYPTO_DEV_SP_CCP
>  
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index 903ddfea8585..1cf197fca93d 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -814,6 +814,15 @@ struct sev_data_snp_commit {
>  
>  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
>  
> +/**
> + * sev_module_init - perform PSP module initialization
> + *
> + * Returns:
> + * 0 if the PSP module is successfully initialized
> + * -%ENODEV    if the PSP module initialization fails

There are more possible return values in the sp_mod_init() path than
just ENODEV. So maybe just say that it returns a negative value on error
unless you want to chase them all down.

> + */
> +int __init sev_module_init(void);
> +
>  /**
>   * sev_platform_init - perform SEV INIT command
>   *
> @@ -948,6 +957,8 @@ void snp_free_firmware_page(void *addr);
>  
>  #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
>  
> +static inline int __init sev_module_init(void) { return -ENODEV }

Remove the "__init".

Although I'm not sure this is even needed since it will only be called
by KVM and CONFIG_KVM_AMD_SEV depends on CONFIG_CRYPTO_DEV_SP_PSP. Plus,
the function itself is only defined under a specific config.

Thanks,
Tom

> +
>  static inline int
>  sev_platform_status(struct sev_user_data_status *status, int *error) { return -ENODEV; }
>