Re: [PATCH v7 18/20] cxl: bypass cpu_cache_invalidate_memregion() when in test config

[Jonathan Cameron <Jonathan.Cameron@Huawei.com>]

On Wed, 30 Nov 2022 12:23:13 -0700
Dave Jiang <dave.jiang@intel.com> wrote:

> Bypass cpu_cache_invalidate_memregion() and checks when doing testing
> using CONFIG_NVDIMM_SECURITY_TEST flag. The bypass allows testing on
> QEMU where cpu_cache_has_invalidate_memregion() fails. Usage of
> cpu_cache_invalidate_memregion() is not needed for cxl_test security
> testing.
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Subject to naming discussion resolving, this looks good to me..

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/cxl/security.c |   35 ++++++++++++++++++++++++++++++-----
>  1 file changed, 30 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/cxl/security.c b/drivers/cxl/security.c
> index cbd005ceb091..2b5088af8fc4 100644
> --- a/drivers/cxl/security.c
> +++ b/drivers/cxl/security.c
> @@ -111,6 +111,31 @@ static int cxl_pmem_security_freeze(struct nvdimm *nvdimm)
>  	return cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_FREEZE_SECURITY, NULL, 0, NULL, 0);
>  }
>  
> +static bool cxl_has_invalidate_memregion(struct cxl_nvdimm *cxl_nvd)
> +{
> +	if (!cpu_cache_has_invalidate_memregion()) {
> +		if (IS_ENABLED(CONFIG_NVDIMM_SECURITY_TEST)) {
> +			dev_warn_once(&cxl_nvd->dev,
> +				      "Bypassing cpu_cache_has_invalidate_memregion() check for testing!\n");
> +			return true;
> +		}
> +		return false;
> +	}
> +
> +	return true;
> +}
> +
> +static void cxl_invalidate_memregion(struct cxl_nvdimm *cxl_nvd)
> +{
> +	if (IS_ENABLED(CONFIG_NVDIMM_SECURITY_TEST)) {
> +		dev_warn_once(&cxl_nvd->dev,
> +			      "Bypassing cpu_cache_invalidate_memergion() for testing!\n");
> +		return;
> +	}
> +
> +	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
> +}
> +
>  static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
>  				    const struct nvdimm_key_data *key_data)
>  {
> @@ -120,7 +145,7 @@ static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
>  	u8 pass[NVDIMM_PASSPHRASE_LEN];
>  	int rc;
>  
> -	if (!cpu_cache_has_invalidate_memregion())
> +	if (!cxl_has_invalidate_memregion(cxl_nvd))
>  		return -EINVAL;
>  
>  	memcpy(pass, key_data->data, NVDIMM_PASSPHRASE_LEN);
> @@ -130,7 +155,7 @@ static int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
>  		return rc;
>  
>  	/* DIMM unlocked, invalidate all CPU caches before we read it */
> -	cpu_cache_invalidate_memregion(IORES_DESC_PERSISTENT_MEMORY);
> +	cxl_invalidate_memregion(cxl_nvd);
>  	return 0;
>  }
>  
> @@ -144,21 +169,21 @@ static int cxl_pmem_security_passphrase_erase(struct nvdimm *nvdimm,
>  	struct cxl_pass_erase erase;
>  	int rc;
>  
> -	if (!cpu_cache_has_invalidate_memregion())
> +	if (!cxl_has_invalidate_memregion(cxl_nvd))
>  		return -EINVAL;
>  
>  	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);
> +	cxl_invalidate_memregion(cxl_nvd);
>  	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_PASSPHRASE_SECURE_ERASE,
>  			       &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);
> +	cxl_invalidate_memregion(cxl_nvd);
>  	return 0;
>  }
>  
> 
>