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[PATCH v3 3/4] crypto: ccp: Add support to enable CipherTextHiding on SNP_INIT_EX

Ashish Kalra posted 4 patches 7 months, 4 weeks ago
There is a newer version of this series
[PATCH v3 3/4] crypto: ccp: Add support to enable CipherTextHiding on SNP_INIT_EX
Posted by Ashish Kalra 7 months, 4 weeks ago 
From: Ashish Kalra <ashish.kalra@amd.com>

Ciphertext hiding needs to be enabled on SNP_INIT_EX.

Add two new arguments to sev_platform_init_args to allow KVM
module to specify during SNP initialization if CipherTextHiding
feature is to be enabled and the maximum ASID usable for an
SEV-SNP guest when CipherTextHiding feature is enabled.

Add new API interface to indicate if SEV-SNP CipherTextHiding
feature is supported and enabled in the Platform/BIOS.

Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 drivers/crypto/ccp/sev-dev.c | 31 ++++++++++++++++++++++++++++---
 include/linux/psp-sev.h      | 18 ++++++++++++++++--
 2 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index f4f8a8905115..ca4b156598de 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -1073,6 +1073,25 @@ static void snp_set_hsave_pa(void *arg)
 	wrmsrq(MSR_VM_HSAVE_PA, 0);
 }
 
+bool is_sev_snp_ciphertext_hiding_supported(void)
+{
+	struct psp_device *psp = psp_master;
+	struct sev_device *sev;
+
+	sev = psp->sev_data;
+
+	/*
+	 * Check if CipherTextHiding feature is supported and enabled
+	 * in the Platform/BIOS.
+	 */
+	if ((sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
+	    sev->snp_plat_status.ciphertext_hiding_cap)
+		return true;
+
+	return false;
+}
+EXPORT_SYMBOL_GPL(is_sev_snp_ciphertext_hiding_supported);
+
 static void snp_get_platform_data(void)
 {
 	struct sev_device *sev = psp_master->sev_data;
@@ -1147,7 +1166,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
 	return 0;
 }
 
-static int __sev_snp_init_locked(int *error)
+static int __sev_snp_init_locked(int *error, bool cipher_text_hiding_en, unsigned int snp_max_snp_asid)
 {
 	struct psp_device *psp = psp_master;
 	struct sev_data_snp_init_ex data;
@@ -1208,6 +1227,12 @@ static int __sev_snp_init_locked(int *error)
 		}
 
 		memset(&data, 0, sizeof(data));
+
+		if (cipher_text_hiding_en) {
+			data.ciphertext_hiding_en = 1;
+			data.max_snp_asid = snp_max_snp_asid;
+		}
+
 		data.init_rmp = 1;
 		data.list_paddr_en = 1;
 		data.list_paddr = __psp_pa(snp_range_list);
@@ -1392,7 +1417,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
 	if (sev->state == SEV_STATE_INIT)
 		return 0;
 
-	rc = __sev_snp_init_locked(&args->error);
+	rc = __sev_snp_init_locked(&args->error, args->cipher_text_hiding_en, args->snp_max_snp_asid);
 	if (rc && rc != -ENODEV)
 		return rc;
 
@@ -1475,7 +1500,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
 {
 	int error, rc;
 
-	rc = __sev_snp_init_locked(&error);
+	rc = __sev_snp_init_locked(&error, false, 0);
 	if (rc) {
 		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
 		return rc;
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index 0149d4a6aceb..af45e3e372f5 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
 struct sev_data_snp_init_ex {
 	u32 init_rmp:1;
 	u32 list_paddr_en:1;
-	u32 rsvd:30;
+	u32 rapl_dis:1;
+	u32 ciphertext_hiding_en:1;
+	u32 rsvd:28;
 	u32 rsvd1;
 	u64 list_paddr;
-	u8  rsvd2[48];
+	u16 max_snp_asid;
+	u8  rsvd2[46];
 } __packed;
 
 /**
@@ -798,10 +801,16 @@ struct sev_data_snp_shutdown_ex {
  * @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
+ *  @cipher_text_hiding_en: True if SEV-SNP CipherTextHiding support is
+ *  enabled
+ *  @snp_max_snp_asid: maximum ASID usable for SEV-SNP guest if
+ *  CipherTextHiding is enabled
  */
 struct sev_platform_init_args {
 	int error;
 	bool probe;
+	bool cipher_text_hiding_en;
+	unsigned int snp_max_snp_asid;
 };
 
 /**
@@ -841,6 +850,8 @@ struct snp_feature_info {
 	u32 edx;
 } __packed;
 
+#define SNP_CIPHER_TEXT_HIDING_SUPPORTED	BIT(3)
+
 #ifdef CONFIG_CRYPTO_DEV_SP_PSP
 
 /**
@@ -984,6 +995,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
 void *snp_alloc_firmware_page(gfp_t mask);
 void snp_free_firmware_page(void *addr);
 void sev_platform_shutdown(void);
+bool is_sev_snp_ciphertext_hiding_supported(void);
 
 #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
 
@@ -1020,6 +1032,8 @@ static inline void snp_free_firmware_page(void *addr) { }
 
 static inline void sev_platform_shutdown(void) { }
 
+static inline bool is_sev_snp_ciphertext_hiding_supported(void) { return FALSE; }
+
 #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
 
 #endif	/* __PSP_SEV_H__ */
-- 
2.34.1
Re: [PATCH v3 3/4] crypto: ccp: Add support to enable CipherTextHiding on SNP_INIT_EX
Posted by kernel test robot 7 months, 1 week ago 
Hi Ashish,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20250417]
[cannot apply to herbert-cryptodev-2.6/master herbert-crypto-2.6/master kvm/queue kvm/next linus/master kvm/linux-next v6.15-rc3 v6.15-rc2 v6.15-rc1 v6.15-rc5]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ashish-Kalra/crypto-ccp-New-bit-field-definitions-for-SNP_PLATFORM_STATUS-command/20250422-082725
base:   next-20250417
patch link:    https://lore.kernel.org/r/94ffa7595fca67cfdcd2352354791bdb6ac00499.1745279916.git.ashish.kalra%40amd.com
patch subject: [PATCH v3 3/4] crypto: ccp: Add support to enable CipherTextHiding on SNP_INIT_EX
config: i386-buildonly-randconfig-002-20250422 (https://download.01.org/0day-ci/archive/20250507/202505071309.cJl7zfy2-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250507/202505071309.cJl7zfy2-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202505071309.cJl7zfy2-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/x86/kvm/svm/svm.c:24:
>> include/linux/psp-sev.h:1035:74: error: use of undeclared identifier 'FALSE'
    1035 | static inline bool is_sev_snp_ciphertext_hiding_supported(void) { return FALSE; }
         |                                                                          ^
   1 error generated.


vim +/FALSE +1035 include/linux/psp-sev.h

  1034	
> 1035	static inline bool is_sev_snp_ciphertext_hiding_supported(void) { return FALSE; }
  1036	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
Re: [PATCH v3 3/4] crypto: ccp: Add support to enable CipherTextHiding on SNP_INIT_EX
Posted by Tom Lendacky 7 months, 3 weeks ago 
On 4/21/25 19:25, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
> 
> Ciphertext hiding needs to be enabled on SNP_INIT_EX.
> 
> Add two new arguments to sev_platform_init_args to allow KVM
> module to specify during SNP initialization if CipherTextHiding
> feature is to be enabled and the maximum ASID usable for an
> SEV-SNP guest when CipherTextHiding feature is enabled.
> 
> Add new API interface to indicate if SEV-SNP CipherTextHiding
> feature is supported and enabled in the Platform/BIOS.
> 
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
>  drivers/crypto/ccp/sev-dev.c | 31 ++++++++++++++++++++++++++++---
>  include/linux/psp-sev.h      | 18 ++++++++++++++++--
>  2 files changed, 44 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index f4f8a8905115..ca4b156598de 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -1073,6 +1073,25 @@ static void snp_set_hsave_pa(void *arg)
>  	wrmsrq(MSR_VM_HSAVE_PA, 0);
>  }
>  
> +bool is_sev_snp_ciphertext_hiding_supported(void)

sev_is_snp_ciphertext_hiding_supported

> +{
> +	struct psp_device *psp = psp_master;
> +	struct sev_device *sev;
> +
> +	sev = psp->sev_data;
> +
> +	/*
> +	 * Check if CipherTextHiding feature is supported and enabled
> +	 * in the Platform/BIOS.

I think this should be expanded a bit to indicate why both the feature
info and the platform status fields have to be checked.

> +	 */
> +	if ((sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
> +	    sev->snp_plat_status.ciphertext_hiding_cap)
> +		return true;
> +
> +	return false;

And then just make this:

  return (sev->feat_info.ecx & SNP_CIPHER_TEXT_HIDING_SUPPORTED) &&
	 sev->snp_plat_status.ciphertext_hiding_cap);

> +}
> +EXPORT_SYMBOL_GPL(is_sev_snp_ciphertext_hiding_supported);
> +
>  static void snp_get_platform_data(void)
>  {
>  	struct sev_device *sev = psp_master->sev_data;
> @@ -1147,7 +1166,7 @@ static int snp_filter_reserved_mem_regions(struct resource *rs, void *arg)
>  	return 0;
>  }
>  
> -static int __sev_snp_init_locked(int *error)
> +static int __sev_snp_init_locked(int *error, bool cipher_text_hiding_en, unsigned int snp_max_snp_asid)
>  {
>  	struct psp_device *psp = psp_master;
>  	struct sev_data_snp_init_ex data;
> @@ -1208,6 +1227,12 @@ static int __sev_snp_init_locked(int *error)
>  		}
>  
>  		memset(&data, 0, sizeof(data));
> +
> +		if (cipher_text_hiding_en) {
> +			data.ciphertext_hiding_en = 1;
> +			data.max_snp_asid = snp_max_snp_asid;
> +		}
> +
>  		data.init_rmp = 1;
>  		data.list_paddr_en = 1;
>  		data.list_paddr = __psp_pa(snp_range_list);
> @@ -1392,7 +1417,7 @@ static int _sev_platform_init_locked(struct sev_platform_init_args *args)
>  	if (sev->state == SEV_STATE_INIT)
>  		return 0;
>  
> -	rc = __sev_snp_init_locked(&args->error);
> +	rc = __sev_snp_init_locked(&args->error, args->cipher_text_hiding_en, args->snp_max_snp_asid);
>  	if (rc && rc != -ENODEV)
>  		return rc;
>  
> @@ -1475,7 +1500,7 @@ static int snp_move_to_init_state(struct sev_issue_cmd *argp, bool *shutdown_req
>  {
>  	int error, rc;
>  
> -	rc = __sev_snp_init_locked(&error);
> +	rc = __sev_snp_init_locked(&error, false, 0);
>  	if (rc) {
>  		argp->error = SEV_RET_INVALID_PLATFORM_STATE;
>  		return rc;
> diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
> index 0149d4a6aceb..af45e3e372f5 100644
> --- a/include/linux/psp-sev.h
> +++ b/include/linux/psp-sev.h
> @@ -746,10 +746,13 @@ struct sev_data_snp_guest_request {
>  struct sev_data_snp_init_ex {
>  	u32 init_rmp:1;
>  	u32 list_paddr_en:1;
> -	u32 rsvd:30;
> +	u32 rapl_dis:1;
> +	u32 ciphertext_hiding_en:1;
> +	u32 rsvd:28;
>  	u32 rsvd1;
>  	u64 list_paddr;
> -	u8  rsvd2[48];
> +	u16 max_snp_asid;
> +	u8  rsvd2[46];
>  } __packed;
>  
>  /**
> @@ -798,10 +801,16 @@ struct sev_data_snp_shutdown_ex {
>   * @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
> + *  @cipher_text_hiding_en: True if SEV-SNP CipherTextHiding support is

s/is/is to be/

Thanks,
Tom

> + *  enabled
> + *  @snp_max_snp_asid: maximum ASID usable for SEV-SNP guest if
> + *  CipherTextHiding is enabled
>   */
>  struct sev_platform_init_args {
>  	int error;
>  	bool probe;
> +	bool cipher_text_hiding_en;
> +	unsigned int snp_max_snp_asid;
>  };
>  
>  /**
> @@ -841,6 +850,8 @@ struct snp_feature_info {
>  	u32 edx;
>  } __packed;
>  
> +#define SNP_CIPHER_TEXT_HIDING_SUPPORTED	BIT(3)
> +
>  #ifdef CONFIG_CRYPTO_DEV_SP_PSP
>  
>  /**
> @@ -984,6 +995,7 @@ void *psp_copy_user_blob(u64 uaddr, u32 len);
>  void *snp_alloc_firmware_page(gfp_t mask);
>  void snp_free_firmware_page(void *addr);
>  void sev_platform_shutdown(void);
> +bool is_sev_snp_ciphertext_hiding_supported(void);
>  
>  #else	/* !CONFIG_CRYPTO_DEV_SP_PSP */
>  
> @@ -1020,6 +1032,8 @@ static inline void snp_free_firmware_page(void *addr) { }
>  
>  static inline void sev_platform_shutdown(void) { }
>  
> +static inline bool is_sev_snp_ciphertext_hiding_supported(void) { return FALSE; }
> +
>  #endif	/* CONFIG_CRYPTO_DEV_SP_PSP */
>  
>  #endif	/* __PSP_SEV_H__ */

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