[RFC PATCH 4/5] rpmb: create virtio rpmb frontend driver [WIP]

From: Alex Bennée
Date: Wed Mar 03 2021 - 12:50:09 EST

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Previous message: Alex Bennée: "[RFC PATCH 5/5] tools/rpmb: simple test sequence"
In reply to: Alex Bennée: "[RFC PATCH 5/5] tools/rpmb: simple test sequence"
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This implements a virtio rpmb frontend driver for the RPMB subsystem.

[AJB: the principle difference is all the MAC calculation and
validation is now done in the driver]

Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
Cc: Tomas Winkler <tomas.winkler@xxxxxxxxx>

---
ajb:
- add include linux/slab.h for kzalloc
- include standardised VIRTIO_ID_RPMB
- remove extra frames when sending commands down virtqueue
- clean up out/in sgs - hopefully more conforming
- remove cmd_cap code
---
drivers/char/rpmb/Kconfig | 10 +
drivers/char/rpmb/Makefile | 1 +
drivers/char/rpmb/virtio_rpmb.c | 366 +++++++++++++++++++++++++++++++
include/uapi/linux/virtio_ids.h | 1 +
include/uapi/linux/virtio_rpmb.h | 54 +++++
5 files changed, 432 insertions(+)
create mode 100644 drivers/char/rpmb/virtio_rpmb.c
create mode 100644 include/uapi/linux/virtio_rpmb.h

diff --git a/drivers/char/rpmb/Kconfig b/drivers/char/rpmb/Kconfig
index 9068664a399a..845f458452a5 100644
--- a/drivers/char/rpmb/Kconfig
+++ b/drivers/char/rpmb/Kconfig
@@ -16,3 +16,13 @@ config RPMB_INTF_DEV
help
Say yes here if you want to access RPMB from user space
via character device interface /dev/rpmb%d
+
+config VIRTIO_RPMB
+ tristate "Virtio RPMB character device interface /dev/vrpmb"
+ default n
+ depends on VIRTIO && KEYS
+ select RPMB
+ help
+ Say yes here if you want to access virtio RPMB from user space
+ via character device interface /dev/vrpmb.
+ This device interface is only for guest/frontend virtio driver.
diff --git a/drivers/char/rpmb/Makefile b/drivers/char/rpmb/Makefile
index f54b3f30514b..4b397b50a42c 100644
--- a/drivers/char/rpmb/Makefile
+++ b/drivers/char/rpmb/Makefile
@@ -4,5 +4,6 @@
obj-$(CONFIG_RPMB) += rpmb.o
rpmb-objs += core.o
rpmb-$(CONFIG_RPMB_INTF_DEV) += cdev.o
+obj-$(CONFIG_VIRTIO_RPMB) += virtio_rpmb.o

ccflags-y += -D__CHECK_ENDIAN__
diff --git a/drivers/char/rpmb/virtio_rpmb.c b/drivers/char/rpmb/virtio_rpmb.c
new file mode 100644
index 000000000000..6ade26874a4e
--- /dev/null
+++ b/drivers/char/rpmb/virtio_rpmb.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtio RPMB Front End Driver
+ *
+ * Copyright (c) 2018-2019 Intel Corporation.
+ * Copyright (c) 2021 Linaro Ltd.
+ */
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/err.h>
+#include <linux/scatterlist.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/virtio.h>
+#include <linux/module.h>
+#include <linux/virtio_ids.h>
+#include <linux/fs.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_rpmb.h>
+#include <linux/uaccess.h>
+#include <linux/key.h>
+#include <linux/rpmb.h>
+
+#define RPMB_MAC_SIZE 32
+
+static const char id[] = "RPMB:VIRTIO";
+
+struct virtio_rpmb_info {
+ struct virtqueue *vq;
+ struct mutex lock; /* info lock */
+ wait_queue_head_t have_data;
+ struct rpmb_dev *rdev;
+};
+
+static void virtio_rpmb_recv_done(struct virtqueue *vq)
+{
+ struct virtio_rpmb_info *vi;
+ struct virtio_device *vdev = vq->vdev;
+
+ vi = vq->vdev->priv;
+ if (!vi) {
+ dev_err(&vdev->dev, "Error: no found vi data.\n");
+ return;
+ }
+
+ wake_up(&vi->have_data);
+}
+
+/* static int rpmb_virtio_cmd_seq(struct device *dev, u8 target, */
+/* struct rpmb_cmd *cmds, u32 ncmds) */
+/* { */
+/* struct virtio_device *vdev = dev_to_virtio(dev); */
+/* struct virtio_rpmb_info *vi = vdev->priv; */
+/* unsigned int i; */
+/* struct scatterlist out_frames[3]; */
+/* struct scatterlist in_frames[3]; */
+/* struct scatterlist *sgs[3]; */
+/* unsigned int num_out = 0, num_in = 0; */
+/* size_t sz; */
+/* int ret; */
+/* unsigned int len; */
+
+/* if (ncmds > RPMB_SEQ_CMD_MAX) */
+/* return -EINVAL; */
+
+/* mutex_lock(&vi->lock); */
+
+/* /\* */
+/* * Process the frames - putting in the appropriate out_frames */
+/* * and in_frames before we build our final ordered sgs[] out */
+/* * array. */
+/* *\/ */
+/* for (i = 0; i < ncmds; i++) { */
+/* struct rpmb_cmd *cmd = &cmds[i]; */
+/* sz = sizeof(struct rpmb_frame_jdec) * (cmd->nframes ?: 1); */
+/* if (cmd->flags) { */
+/* sg_init_one(&out_frames[num_out++], cmd->frames, sz); */
+/* } else { */
+/* sg_init_one(&in_frames[num_in++], cmd->frames, sz); */
+/* } */
+/* } */
+
+/* for (i = 0; i < num_out; i++) { */
+/* sgs[i] = &out_frames[i]; */
+/* } */
+/* for (i = 0; i < num_in; i++) { */
+/* sgs[num_out + i] = &in_frames[i]; */
+/* } */
+
+/* dev_warn(dev, "out = %d, in = %d\n", num_out, num_in); */
+
+/* virtqueue_add_sgs(vi->vq, sgs, num_out, num_in, vi, GFP_KERNEL); */
+/* virtqueue_kick(vi->vq); */
+
+/* wait_event(vi->have_data, virtqueue_get_buf(vi->vq, &len)); */
+
+/* ret = 0; */
+
+/* /\* */
+/* * We can't fail at this point, we assume we got a response */
+/* * buffer back. */
+/* *\/ */
+
+/* mutex_unlock(&vi->lock); */
+/* return ret; */
+/* } */
+
+static void * rpmb_virtio_get_key(struct device *dev, key_serial_t keyid)
+{
+ key_ref_t keyref;
+ struct key *key;
+ void *ptr = NULL;
+
+ keyref = lookup_user_key(keyid, 0, KEY_NEED_SEARCH);
+ if (IS_ERR(keyref))
+ return NULL;
+
+ key = key_ref_to_ptr(keyref);
+
+ if (key->datalen != RPMB_MAC_SIZE)
+ dev_err(dev, "Invalid key size (%d)", key->datalen);
+ else
+ ptr = key->payload.data[0];
+
+ key_put(key);
+ return ptr;
+}
+
+static int rpmb_virtio_program_key(struct device *dev, u8 target, key_serial_t keyid)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+ struct virtio_rpmb_info *vi = vdev->priv;
+ const void *key = rpmb_virtio_get_key(dev, keyid);
+
+ if (key) {
+ struct scatterlist out_frame;
+ struct scatterlist in_frame;
+ struct scatterlist *sgs[2];
+ unsigned int len;
+ struct virtio_rpmb_frame resp;
+ struct virtio_rpmb_frame cmd = {
+ .req_resp = cpu_to_le16(VIRTIO_RPMB_REQ_PROGRAM_KEY)
+ };
+
+ /* Prepare the command frame & response */
+ memcpy(&cmd.key_mac, key, sizeof(cmd.key_mac));
+
+ mutex_lock(&vi->lock);
+
+ /* Wrap into SG array */
+ sg_init_one(&out_frame, &cmd, sizeof(cmd));
+ sg_init_one(&in_frame, &resp, sizeof(resp));
+ sgs[0] = &out_frame;
+ sgs[1] = &in_frame;
+
+ /* Send it */
+ virtqueue_add_sgs(vi->vq, sgs, 1, 1, vi, GFP_KERNEL);
+ virtqueue_kick(vi->vq);
+ wait_event(vi->have_data, virtqueue_get_buf(vi->vq, &len));
+
+ mutex_unlock(&vi->lock);
+
+ if (le16_to_cpu(resp.req_resp) != VIRTIO_RPMB_RESP_PROGRAM_KEY) {
+ dev_err(dev, "Bad response from device (%x/%x)",
+ le16_to_cpu(resp.req_resp), le16_to_cpu(resp.result));
+ return -EPROTO;
+ }
+
+ /* check the MAC? */
+
+ /* map responses to better errors? */
+ return le16_to_cpu(resp.result) == VIRTIO_RPMB_RES_OK ? 0 : -EIO;
+ } else {
+ return -EINVAL;
+ }
+}
+
+static int rpmb_virtio_get_capacity(struct device *dev, u8 target)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+ u8 capacity;
+
+ virtio_cread(vdev, struct virtio_rpmb_config, capacity, &capacity);
+
+ if (capacity > 0x80) {
+ dev_err(&vdev->dev, "Error: invalid capacity reported.\n");
+ capacity = 0x80;
+ }
+
+ return capacity;
+}
+
+static int rpmb_virtio_get_write_count(struct device *dev, u8 target)
+{
+ struct virtio_device *vdev = dev_to_virtio(dev);
+ struct virtio_rpmb_info *vi = vdev->priv;
+ struct scatterlist out_frame;
+ struct scatterlist in_frame;
+ struct scatterlist *sgs[2];
+ unsigned int len;
+ struct virtio_rpmb_frame resp;
+ struct virtio_rpmb_frame cmd = {
+ .req_resp = cpu_to_le16(VIRTIO_RPMB_REQ_GET_WRITE_COUNTER)
+ };
+
+ mutex_lock(&vi->lock);
+
+ /* Wrap into SG array */
+ sg_init_one(&out_frame, &cmd, sizeof(cmd));
+ sg_init_one(&in_frame, &resp, sizeof(resp));
+ sgs[0] = &out_frame;
+ sgs[1] = &in_frame;
+
+ /* Send it */
+ virtqueue_add_sgs(vi->vq, sgs, 1, 1, vi, GFP_KERNEL);
+ virtqueue_kick(vi->vq);
+ wait_event(vi->have_data, virtqueue_get_buf(vi->vq, &len));
+
+ mutex_unlock(&vi->lock);
+
+ if (le16_to_cpu(resp.req_resp) != VIRTIO_RPMB_RESP_GET_COUNTER) {
+ dev_err(dev, "failed to program key (%x/%x)",
+ le16_to_cpu(resp.req_resp), le16_to_cpu(resp.result));
+ return -EPROTO;
+ }
+
+ return le16_to_cpu(resp.result) == VIRTIO_RPMB_RES_OK ? be32_to_cpu(resp.write_counter) : -EIO;
+}
+
+static struct rpmb_ops rpmb_virtio_ops = {
+ .program_key = rpmb_virtio_program_key,
+ .get_capacity = rpmb_virtio_get_capacity,
+ .get_write_count = rpmb_virtio_get_write_count,
+ /* .write_blocks = rpmb_virtio_write_blocks, */
+ /* .read_blocks = rpmb_virtio_read_blocks, */
+ .auth_method = RPMB_HMAC_ALGO_SHA_256,
+};
+
+static int rpmb_virtio_dev_init(struct virtio_rpmb_info *vi)
+{
+ int ret = 0;
+ struct device *dev = &vi->vq->vdev->dev;
+ struct virtio_device *vdev = dev_to_virtio(dev);
+ u8 max_wr, max_rd;
+
+ virtio_cread(vdev, struct virtio_rpmb_config,
+ max_wr_cnt, &max_wr);
+ virtio_cread(vdev, struct virtio_rpmb_config,
+ max_rd_cnt, &max_rd);
+
+ rpmb_virtio_ops.dev_id_len = strlen(id);
+ rpmb_virtio_ops.dev_id = id;
+ rpmb_virtio_ops.wr_cnt_max = max_wr;
+ rpmb_virtio_ops.rd_cnt_max = max_rd;
+ rpmb_virtio_ops.block_size = 1;
+
+ vi->rdev = rpmb_dev_register(dev, 0, &rpmb_virtio_ops);
+ if (IS_ERR(vi->rdev)) {
+ ret = PTR_ERR(vi->rdev);
+ goto err;
+ }
+
+ dev_set_drvdata(dev, vi);
+err:
+ return ret;
+}
+
+static int virtio_rpmb_init(struct virtio_device *vdev)
+{
+ int ret;
+ struct virtio_rpmb_info *vi;
+
+ vi = kzalloc(sizeof(*vi), GFP_KERNEL);
+ if (!vi)
+ return -ENOMEM;
+
+ init_waitqueue_head(&vi->have_data);
+ mutex_init(&vi->lock);
+ vdev->priv = vi;
+
+ /* We expect a single virtqueue. */
+ vi->vq = virtio_find_single_vq(vdev, virtio_rpmb_recv_done, "request");
+ if (IS_ERR(vi->vq)) {
+ dev_err(&vdev->dev, "get single vq failed!\n");
+ ret = PTR_ERR(vi->vq);
+ goto err;
+ }
+
+ /* create vrpmb device. */
+ ret = rpmb_virtio_dev_init(vi);
+ if (ret) {
+ dev_err(&vdev->dev, "create vrpmb device failed.\n");
+ goto err;
+ }
+
+ dev_info(&vdev->dev, "init done!\n");
+
+ return 0;
+
+err:
+ kfree(vi);
+ return ret;
+}
+
+static void virtio_rpmb_remove(struct virtio_device *vdev)
+{
+ struct virtio_rpmb_info *vi;
+
+ vi = vdev->priv;
+ if (!vi)
+ return;
+
+ if (wq_has_sleeper(&vi->have_data))
+ wake_up(&vi->have_data);
+
+ rpmb_dev_unregister(vi->rdev);
+
+ if (vdev->config->reset)
+ vdev->config->reset(vdev);
+
+ if (vdev->config->del_vqs)
+ vdev->config->del_vqs(vdev);
+
+ kfree(vi);
+}
+
+static int virtio_rpmb_probe(struct virtio_device *vdev)
+{
+ return virtio_rpmb_init(vdev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtio_rpmb_freeze(struct virtio_device *vdev)
+{
+ virtio_rpmb_remove(vdev);
+ return 0;
+}
+
+static int virtio_rpmb_restore(struct virtio_device *vdev)
+{
+ return virtio_rpmb_init(vdev);
+}
+#endif
+
+static struct virtio_device_id id_table[] = {
+ { VIRTIO_ID_RPMB, VIRTIO_DEV_ANY_ID },
+ { 0 },
+};
+
+static struct virtio_driver virtio_rpmb_driver = {
+ .driver.name = KBUILD_MODNAME,
+ .driver.owner = THIS_MODULE,
+ .id_table = id_table,
+ .probe = virtio_rpmb_probe,
+ .remove = virtio_rpmb_remove,
+#ifdef CONFIG_PM_SLEEP
+ .freeze = virtio_rpmb_freeze,
+ .restore = virtio_rpmb_restore,
+#endif
+};
+
+module_virtio_driver(virtio_rpmb_driver);
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+MODULE_DESCRIPTION("Virtio rpmb frontend driver");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
index bc1c0621f5ed..934df72714e2 100644
--- a/include/uapi/linux/virtio_ids.h
+++ b/include/uapi/linux/virtio_ids.h
@@ -53,6 +53,7 @@
#define VIRTIO_ID_MEM 24 /* virtio mem */
#define VIRTIO_ID_FS 26 /* virtio filesystem */
#define VIRTIO_ID_PMEM 27 /* virtio pmem */
+#define VIRTIO_ID_RPMB 28 /* virtio RPMB */
#define VIRTIO_ID_MAC80211_HWSIM 29 /* virtio mac80211-hwsim */

#endif /* _LINUX_VIRTIO_IDS_H */
diff --git a/include/uapi/linux/virtio_rpmb.h b/include/uapi/linux/virtio_rpmb.h
new file mode 100644
index 000000000000..f048cd968210
--- /dev/null
+++ b/include/uapi/linux/virtio_rpmb.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */
+
+#ifndef _UAPI_LINUX_VIRTIO_RPMB_H
+#define _UAPI_LINUX_VIRTIO_RPMB_H
+
+#include <linux/types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
+
+struct virtio_rpmb_config {
+ __u8 capacity;
+ __u8 max_wr_cnt;
+ __u8 max_rd_cnt;
+} __attribute__((packed));
+
+/* RPMB Request Types (in .req_resp) */
+#define VIRTIO_RPMB_REQ_PROGRAM_KEY 0x0001
+#define VIRTIO_RPMB_REQ_GET_WRITE_COUNTER 0x0002
+#define VIRTIO_RPMB_REQ_DATA_WRITE 0x0003
+#define VIRTIO_RPMB_REQ_DATA_READ 0x0004
+#define VIRTIO_RPMB_REQ_RESULT_READ 0x0005
+
+/* RPMB Response Types (in .req_resp) */
+#define VIRTIO_RPMB_RESP_PROGRAM_KEY 0x0100
+#define VIRTIO_RPMB_RESP_GET_COUNTER 0x0200
+#define VIRTIO_RPMB_RESP_DATA_WRITE 0x0300
+#define VIRTIO_RPMB_RESP_DATA_READ 0x0400
+
+struct virtio_rpmb_frame {
+ __u8 stuff[196];
+ __u8 key_mac[32];
+ __u8 data[256];
+ __u8 nonce[16];
+ __be32 write_counter;
+ __be16 address;
+ __be16 block_count;
+ __be16 result;
+ __be16 req_resp;
+} __attribute__((packed));
+
+/* RPMB Operation Results (in .result) */
+#define VIRTIO_RPMB_RES_OK 0x0000
+#define VIRTIO_RPMB_RES_GENERAL_FAILURE 0x0001
+#define VIRTIO_RPMB_RES_AUTH_FAILURE 0x0002
+#define VIRTIO_RPMB_RES_COUNT_FAILURE 0x0003
+#define VIRTIO_RPMB_RES_ADDR_FAILURE 0x0004
+#define VIRTIO_RPMB_RES_WRITE_FAILURE 0x0005
+#define VIRTIO_RPMB_RES_READ_FAILURE 0x0006
+#define VIRTIO_RPMB_RES_NO_AUTH_KEY 0x0007
+#define VIRTIO_RPMB_RES_WRITE_COUNTER_EXPIRED 0x0080
+
+
+#endif /* _UAPI_LINUX_VIRTIO_RPMB_H */
--
2.20.1

Next message: Michal Hocko: "Re: [PATCH v3 RFC 14/14] mm: speedup page alloc for MPOL_PREFERRED_MANY by adding a NO_SLOWPATH gfp bit"
Previous message: Alex Bennée: "[RFC PATCH 5/5] tools/rpmb: simple test sequence"
In reply to: Alex Bennée: "[RFC PATCH 5/5] tools/rpmb: simple test sequence"
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