Re: [PATCH v2 12/19] cxl/pmem: Add "Passphrase Secure Erase" security command support

[Dave Jiang <dave.jiang@intel.com>]

On 11/7/2022 7:25 AM, Jonathan Cameron wrote:
> On Wed, 21 Sep 2022 08:32:40 -0700
> Dave Jiang <dave.jiang@intel.com> wrote:
> 
>> Create callback function to support the nvdimm_security_ops() ->erase()
>> callback. Translate the operation to send "Passphrase Secure Erase"
>> security command for CXL memory device.
>>
>> When the mem device is secure erased, arch_invalidate_nvdimm_cache() is
>> called in order to invalidate all CPU caches before attempting to access
>> the mem device again.
>>
>> See CXL 2.0 spec section 8.2.9.5.6.6 for reference.
> Update references now 3.0 is out.

I'll do that for the entire series.

> 
>>
>> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> A few minor things inline.
> 
>> ---
>>   drivers/cxl/core/mbox.c      |    1 +
>>   drivers/cxl/cxlmem.h         |    8 ++++++++
>>   drivers/cxl/security.c       |   29 +++++++++++++++++++++++++++++
>>   include/uapi/linux/cxl_mem.h |    1 +
>>   4 files changed, 39 insertions(+)
>>
>> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
>> index 243b01e2de85..88538a7ccc83 100644
>> --- a/drivers/cxl/core/mbox.c
>> +++ b/drivers/cxl/core/mbox.c
>> @@ -70,6 +70,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
>>   	CXL_CMD(DISABLE_PASSPHRASE, 0x40, 0, 0),
>>   	CXL_CMD(FREEZE_SECURITY, 0, 0, 0),
>>   	CXL_CMD(UNLOCK, 0x20, 0, 0),
>> +	CXL_CMD(PASSPHRASE_ERASE, 0x40, 0, 0),
>>   };
>>   
>>   /*
>> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
>> index 4e6897e8eb7d..1266df3b2d3d 100644
>> --- a/drivers/cxl/cxlmem.h
>> +++ b/drivers/cxl/cxlmem.h
>> @@ -278,6 +278,7 @@ enum cxl_opcode {
>>   	CXL_MBOX_OP_DISABLE_PASSPHRASE	= 0x4502,
>>   	CXL_MBOX_OP_UNLOCK		= 0x4503,
>>   	CXL_MBOX_OP_FREEZE_SECURITY	= 0x4504,
>> +	CXL_MBOX_OP_PASSPHRASE_ERASE	= 0x4505,
> Hmm. Name is a bit ambiguous. Is it erasing the passphrase or the data?
> Perhaps full
> 	CXL_MBOX_O_PASSPHRASE_SECURE_ERASE is a little better?

Ok, will update.

> 
>>   	CXL_MBOX_OP_MAX			= 0x10000
>>   };
>>   
>> @@ -400,6 +401,13 @@ struct cxl_disable_pass {
>>   	u8 pass[NVDIMM_PASSPHRASE_LEN];
>>   } __packed;
>>   
>> +/* passphrase erase payload */
> Same here.

Ok.

> 
>> +struct cxl_pass_erase {
>> +	u8 type;
>> +	u8 reserved[31];
>> +	u8 pass[NVDIMM_PASSPHRASE_LEN];
>> +} __packed;
>> +
>>   enum {
>>   	CXL_PMEM_SEC_PASS_MASTER = 0,
>>   	CXL_PMEM_SEC_PASS_USER,
>> diff --git a/drivers/cxl/security.c b/drivers/cxl/security.c
>> index 8bfdcb58d381..df4cf26e366a 100644
>> --- a/drivers/cxl/security.c
>> +++ b/drivers/cxl/security.c
>> @@ -128,12 +128,41 @@ static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
>>   	return 0;
>>   }
>>   
>> +static int cxl_pmem_security_passphrase_erase(struct nvdimm *nvdimm,
>> +					      const struct nvdimm_key_data *key,
>> +					      enum nvdimm_passphrase_type ptype)
>> +{
>> +	struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
>> +	struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
>> +	struct cxl_dev_state *cxlds = cxlmd->cxlds;
>> +	struct cxl_pass_erase erase;
>> +	int rc;
>> +
>> +	if (!cpu_cache_has_invalidate_memregion())
>> +		return -EOPNOTSUPP;
>> +
>> +	erase.type = ptype == NVDIMM_MASTER ?
>> +		CXL_PMEM_SEC_PASS_MASTER : CXL_PMEM_SEC_PASS_USER;
>> +	memcpy(erase.pass, key->data, NVDIMM_PASSPHRASE_LEN);
>> +	/* Flush all cache before we erase mem device */
>> +	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
>> +	rc =  cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_PASSPHRASE_ERASE,
> 
> extra space.

Yup. Thanks!

> 
>> +				&erase, sizeof(erase), NULL, 0);
>> +	if (rc < 0)
>> +		return rc;
>> +
>> +	/* mem device erased, invalidate all CPU caches before data is read */
>> +	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
>> +	return 0;
>> +}
>> +
>>   static const struct nvdimm_security_ops __cxl_security_ops = {
>>   	.get_flags = cxl_pmem_get_security_flags,
>>   	.change_key = cxl_pmem_security_change_key,
>>   	.disable = cxl_pmem_security_disable,
>>   	.freeze = cxl_pmem_security_freeze,
>>   	.unlock = cxl_pmem_security_unlock,
>> +	.erase = cxl_pmem_security_passphrase_erase,
>>   };
>>   
>>   const struct nvdimm_security_ops *cxl_security_ops = &__cxl_security_ops;
>> diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
>> index 95dca8d4584f..6da25f2e1bf9 100644
>> --- a/include/uapi/linux/cxl_mem.h
>> +++ b/include/uapi/linux/cxl_mem.h
>> @@ -46,6 +46,7 @@
>>   	___C(DISABLE_PASSPHRASE, "Disable Passphrase"),			  \
>>   	___C(FREEZE_SECURITY, "Freeze Security"),			  \
>>   	___C(UNLOCK, "Unlock"),						  \
>> +	___C(PASSPHRASE_ERASE, "Passphrase Secure Erase"),		  \
>>   	___C(MAX, "invalid / last command")
>>   
>>   #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
>>
>>
>