[PATCH RFC 11/15] cxl/pmem: Add "Unlock" security command support

[Dave Jiang]

Create callback function to support the nvdimm_security_ops() ->unlock()
callback. Translate the operation to send "Unlock" security command for CXL
mem device.

When the mem device is unlocked, arch_invalidate_nvdimm_cache() is called
in order to invalidate all CPU caches before attempting to access the mem
device.

See CXL 2.0 spec section 8.2.9.5.6.4 for reference.

Signed-off-by: Dave Jiang <dave.ji...@intel.com>
---
 drivers/cxl/cxlmem.h   |    1 +
 drivers/cxl/security.c |   21 +++++++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index ced85be291f3..ae8ccd484491 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -253,6 +253,7 @@ enum cxl_opcode {
        CXL_MBOX_OP_GET_SECURITY_STATE  = 0x4500,
        CXL_MBOX_OP_SET_PASSPHRASE      = 0x4501,
        CXL_MBOX_OP_DISABLE_PASSPHRASE  = 0x4502,
+       CXL_MBOX_OP_UNLOCK              = 0x4503,
        CXL_MBOX_OP_FREEZE_SECURITY     = 0x4504,
        CXL_MBOX_OP_MAX                 = 0x10000
 };
diff --git a/drivers/cxl/security.c b/drivers/cxl/security.c
index 6399266a5908..d15520f280f0 100644
--- a/drivers/cxl/security.c
+++ b/drivers/cxl/security.c
@@ -114,11 +114,32 @@ 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 int cxl_pmem_security_unlock(struct nvdimm *nvdimm,
+                                   const struct nvdimm_key_data *key_data)
+{
+       struct cxl_nvdimm *cxl_nvd = nvdimm_provider_data(nvdimm);
+       struct cxl_memdev *cxlmd = cxl_nvd->cxlmd;
+       struct cxl_dev_state *cxlds = cxlmd->cxlds;
+       u8 pass[NVDIMM_PASSPHRASE_LEN];
+       int rc;
+
+       memcpy(pass, key_data->data, NVDIMM_PASSPHRASE_LEN);
+       rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_UNLOCK,
+                              pass, NVDIMM_PASSPHRASE_LEN, NULL, 0);
+       if (rc < 0)
+               return rc;
+
+       /* DIMM unlocked, invalidate all CPU caches before we read it */
+       arch_invalidate_nvdimm_cache();
+       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,
 };
 
 const struct nvdimm_security_ops *cxl_security_ops = &__cxl_security_ops;