[PATCH 1/8] mmc: add basic support for inline encryption

Eric Biggers
2020-11-12T19:41:19Z

From: Eric Biggers <ebiggers@google.com>

In preparation for adding CQHCI crypto engine (inline encryption)
support, add the code required to make mmc_core and mmc_block aware of
inline encryption. Specifically:

- Add a capability flag MMC_CAP2_CRYPTO to struct mmc_host. Drivers
will set this if the host and driver support inline encryption.

- Embed a blk_keyslot_manager in struct mmc_host. Drivers will
initialize this if the host and driver support inline encryption.
mmc_block registers this keyslot manager with the request_queue of any
MMC card attached to the host. mmc_core destroys this keyslot manager
when freeing the mmc_host.

- Make mmc_block copy the crypto keyslot and crypto data unit number
from struct request to struct mmc_request, so that drivers will have
access to them.

- If the MMC host is reset, reprogram all the keyslots to ensure that
the software state stays in sync with the hardware state.

Co-developed-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
drivers/mmc/core/Kconfig | 8 ++++++
drivers/mmc/core/Makefile | 1 +
drivers/mmc/core/block.c | 3 +++
drivers/mmc/core/core.c | 3 +++
drivers/mmc/core/crypto.c | 54 +++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/crypto.h | 46 +++++++++++++++++++++++++++++++++
drivers/mmc/core/host.c | 2 ++
drivers/mmc/core/queue.c | 3 +++
include/linux/mmc/core.h | 6 +++++
include/linux/mmc/host.h | 7 +++++
10 files changed, 133 insertions(+)
create mode 100644 drivers/mmc/core/crypto.c
create mode 100644 drivers/mmc/core/crypto.h

diff --git a/drivers/mmc/core/Kconfig b/drivers/mmc/core/Kconfig
index c12fe13e4b147..ae8b69aee6190 100644
--- a/drivers/mmc/core/Kconfig
+++ b/drivers/mmc/core/Kconfig
@@ -81,3 +81,11 @@ config MMC_TEST
This driver is only of interest to those developing or
testing a host driver. Most people should say N here.

+config MMC_CRYPTO
+ bool "MMC Crypto Engine Support"
+ depends on BLK_INLINE_ENCRYPTION
+ help
+ Enable Crypto Engine Support in MMC.
+ Enabling this makes it possible for the kernel to use the crypto
+ capabilities of the MMC device (if present) to perform crypto
+ operations on data being transferred to/from the device.
diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 95ffe008ebdf8..6a907736cd7a5 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_MMC_BLOCK) += mmc_block.o
mmc_block-objs := block.o queue.o
obj-$(CONFIG_MMC_TEST) += mmc_test.o
obj-$(CONFIG_SDIO_UART) += sdio_uart.o
+mmc_core-$(CONFIG_MMC_CRYPTO) += crypto.o
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 8d3df0be0355c..eaf2f10743260 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -51,6 +51,7 @@
#include "block.h"
#include "core.h"
#include "card.h"
+#include "crypto.h"
#include "host.h"
#include "bus.h"
#include "mmc_ops.h"
@@ -1247,6 +1248,8 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,

memset(brq, 0, sizeof(struct mmc_blk_request));

+ mmc_crypto_prepare_req(mqrq);
+
brq->mrq.data = &brq->data;
brq->mrq.tag = req->tag;

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index d42037f0f10d7..275de270232b3 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -37,6 +37,7 @@

#include "core.h"
#include "card.h"
+#include "crypto.h"
#include "bus.h"
#include "host.h"
#include "sdio_bus.h"
@@ -992,6 +993,8 @@ void mmc_set_initial_state(struct mmc_host *host)
host->ops->hs400_enhanced_strobe(host, &host->ios);

mmc_set_ios(host);
+
+ mmc_crypto_set_initial_state(host);
}

/**
diff --git a/drivers/mmc/core/crypto.c b/drivers/mmc/core/crypto.c
new file mode 100644
index 0000000000000..4f47eb4740db0
--- /dev/null
+++ b/drivers/mmc/core/crypto.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MMC crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#include <linux/blk-crypto.h>
+#include <linux/mmc/host.h>
+
+#include "core.h"
+#include "crypto.h"
+#include "queue.h"
+
+void mmc_crypto_set_initial_state(struct mmc_host *host)
+{
+ /* Reset might clear all keys, so reprogram all the keys. */
+ if (host->caps2 & MMC_CAP2_CRYPTO)
+ blk_ksm_reprogram_all_keys(&host->ksm);
+}
+
+void mmc_crypto_free_host(struct mmc_host *host)
+{
+ if (host->caps2 & MMC_CAP2_CRYPTO)
+ blk_ksm_destroy(&host->ksm);
+}
+
+void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host)
+{
+ if (host->caps2 & MMC_CAP2_CRYPTO)
+ blk_ksm_register(&host->ksm, q);
+}
+EXPORT_SYMBOL_GPL(mmc_crypto_setup_queue);
+
+void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq)
+{
+ struct request *req = mmc_queue_req_to_req(mqrq);
+ struct mmc_request *mrq = &mqrq->brq.mrq;
+
+ if (!req->crypt_keyslot)
+ return;
+
+ mrq->crypto_enabled = true;
+ mrq->crypto_key_slot = blk_ksm_get_slot_idx(req->crypt_keyslot);
+
+ /*
+ * For now we assume that all MMC drivers set max_dun_bytes_supported=4,
+ * which is the limit for CQHCI crypto. So all DUNs should be 32-bit.
+ */
+ WARN_ON_ONCE(req->crypt_ctx->bc_dun[0] > U32_MAX);
+
+ mrq->data_unit_num = req->crypt_ctx->bc_dun[0];
+}
+EXPORT_SYMBOL_GPL(mmc_crypto_prepare_req);
diff --git a/drivers/mmc/core/crypto.h b/drivers/mmc/core/crypto.h
new file mode 100644
index 0000000000000..4780639b832f4
--- /dev/null
+++ b/drivers/mmc/core/crypto.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * MMC crypto engine (inline encryption) support
+ *
+ * Copyright 2020 Google LLC
+ */
+
+#ifndef _MMC_CORE_CRYPTO_H
+#define _MMC_CORE_CRYPTO_H
+
+struct mmc_host;
+struct mmc_queue_req;
+struct request_queue;
+
+#ifdef CONFIG_MMC_CRYPTO
+
+void mmc_crypto_set_initial_state(struct mmc_host *host);
+
+void mmc_crypto_free_host(struct mmc_host *host);
+
+void mmc_crypto_setup_queue(struct request_queue *q, struct mmc_host *host);
+
+void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq);
+
+#else /* CONFIG_MMC_CRYPTO */
+
+static inline void mmc_crypto_set_initial_state(struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_free_host(struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_setup_queue(struct request_queue *q,
+ struct mmc_host *host)
+{
+}
+
+static inline void mmc_crypto_prepare_req(struct mmc_queue_req *mqrq)
+{
+}
+
+#endif /* !CONFIG_MMC_CRYPTO */
+
+#endif /* _MMC_CORE_CRYPTO_H */
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 96b2ca1f1b06d..d962b9ca0e37a 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -25,6 +25,7 @@
#include <linux/mmc/slot-gpio.h>

#include "core.h"
+#include "crypto.h"
#include "host.h"
#include "slot-gpio.h"
#include "pwrseq.h"
@@ -532,6 +533,7 @@ EXPORT_SYMBOL(mmc_remove_host);
*/
void mmc_free_host(struct mmc_host *host)
{
+ mmc_crypto_free_host(host);
mmc_pwrseq_free(host);
put_device(&host->class_dev);
}
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index de7cb0369c308..d96db852bb91a 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -19,6 +19,7 @@
#include "block.h"
#include "core.h"
#include "card.h"
+#include "crypto.h"
#include "host.h"

#define MMC_DMA_MAP_MERGE_SEGMENTS 512
@@ -405,6 +406,8 @@ static void mmc_setup_queue(struct mmc_queue *mq, struct mmc_card *card)
mutex_init(&mq->complete_lock);

init_waitqueue_head(&mq->wait);
+
+ mmc_crypto_setup_queue(mq->queue, host);
}

static inline bool mmc_merge_capable(struct mmc_host *host)
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 29aa507116261..ab19245e99451 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -162,6 +162,12 @@ struct mmc_request {
bool cap_cmd_during_tfr;

int tag;
+
+#ifdef CONFIG_MMC_CRYPTO
+ bool crypto_enabled;
+ int crypto_key_slot;
+ u32 data_unit_num;
+#endif
};

struct mmc_card;
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index c079b932330f2..550460bf1b37c 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -15,6 +15,7 @@
#include <linux/mmc/card.h>
#include <linux/mmc/pm.h>
#include <linux/dma-direction.h>
+#include <linux/keyslot-manager.h>

struct mmc_ios {
unsigned int clock; /* clock rate */
@@ -377,6 +378,7 @@ struct mmc_host {
#define MMC_CAP2_CQE_DCMD (1 << 24) /* CQE can issue a direct command */
#define MMC_CAP2_AVOID_3_3V (1 << 25) /* Host must negotiate down from 3.3V */
#define MMC_CAP2_MERGE_CAPABLE (1 << 26) /* Host can merge a segment over the segment size */
+#define MMC_CAP2_CRYPTO (1 << 27) /* Host supports inline encryption */

int fixed_drv_type; /* fixed driver type for non-removable media */

@@ -471,6 +473,11 @@ struct mmc_host {
bool cqe_enabled;
bool cqe_on;

+ /* Inline encryption support */
+#ifdef CONFIG_MMC_CRYPTO
+ struct blk_keyslot_manager ksm;
+#endif
+
/* Host Software Queue support */
bool hsq_enabled;

--
2.29.2