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Commit 27aa4d22 authored by Isaac J. Manjarres's avatar Isaac J. Manjarres
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soc: qcom: mem-buf: Add support for restricting memory transfers 



The mem-buf driver follows a supplier and consumer model
to enforce what the instance of the driver on a particular
Virtual Machine (VM) can and cannot do. These roles are
conveyed through the qcom,mem-buf-capabilities property.

A driver on a VM that has the supplier capability is able
to lend and share memory to other VMs, but cannot request
memory from another VM.

In the other direction, a VM with consumer capability is
only capable of requesting memory from other VMs, but cannot
satisfy memory requests from other VMs.

Change-Id: I1d258bdaafbbdb020831afc85c47f44a5ec93940
Signed-off-by: default avatarIsaac J. Manjarres <isaacm@codeaurora.org>
parent 09451a33

drivers/soc/qcom/mem-buf.c

+36 −7
Original line number Diff line number Diff line
@@ -31,6 +31,10 @@ 
#define MEM_BUF_TIMEOUT_MS 2000

#define to_rmt_msg(_work) container_of(_work, struct mem_buf_rmt_msg, work)



#define MEM_BUF_CAP_SUPPLIER	BIT(0)

#define MEM_BUF_CAP_CONSUMER	BIT(1)

#define MEM_BUF_CAP_DUAL (MEM_BUF_CAP_SUPPLIER | MEM_BUF_CAP_CONSUMER)



/* Data structures for requesting/maintaining memory from other VMs */

static dev_t mem_buf_dev_no;

static struct class *mem_buf_class;
@@ -48,6 +52,7 @@ static DEFINE_MUTEX(mem_buf_idr_mutex); 
static DEFINE_IDR(mem_buf_txn_idr);

static struct task_struct *mem_buf_msgq_recv_thr;

static void *mem_buf_hh_msgq_hdl;

static unsigned char mem_buf_capability;



/**

 * enum mem_buf_msg_type: Message types used by the membuf driver for
@@ -747,7 +752,8 @@ static void mem_buf_process_msg(void *buf, size_t size) 
		return;

	}



	if (hdr->msg_type == MEM_BUF_ALLOC_RESP) {

	if ((hdr->msg_type == MEM_BUF_ALLOC_RESP) &&

	    (mem_buf_capability & MEM_BUF_CAP_CONSUMER)) {

		mutex_lock(&mem_buf_idr_mutex);

		txn = idr_find(&mem_buf_txn_idr, hdr->txn_id);

		if (!txn) {
@@ -760,8 +766,9 @@ static void mem_buf_process_msg(void *buf, size_t size) 
		}

		mutex_unlock(&mem_buf_idr_mutex);

		kfree(buf);

	} else if (hdr->msg_type == MEM_BUF_ALLOC_REQ ||

		   hdr->msg_type == MEM_BUF_ALLOC_RELINQUISH) {

	} else if ((hdr->msg_type == MEM_BUF_ALLOC_REQ ||

		    hdr->msg_type == MEM_BUF_ALLOC_RELINQUISH) &&

		   (mem_buf_capability & MEM_BUF_CAP_SUPPLIER)) {

		rmt_msg = kmalloc(sizeof(*rmt_msg), GFP_KERNEL);

		if (!rmt_msg) {

			kfree(buf);
@@ -1265,6 +1272,9 @@ void *mem_buf_alloc(struct mem_buf_allocation_data *alloc_data) 
	struct file *filp;

	struct mem_buf_desc *membuf;



	if (!(mem_buf_capability & MEM_BUF_CAP_CONSUMER))

		return ERR_PTR(-ENOTSUPP);



	if (!alloc_data)

		return ERR_PTR(-EINVAL);
@@ -1517,6 +1527,9 @@ static long mem_buf_dev_ioctl(struct file *filp, unsigned int cmd, 
	switch (cmd) {

	case MEM_BUF_IOC_ALLOC:

	{

		if (!(mem_buf_capability & MEM_BUF_CAP_CONSUMER))

			return -ENOTSUPP;



		fd = mem_buf_alloc_fd(&allocation);



		if (fd < 0)
@@ -1545,13 +1558,29 @@ static const struct file_operations mem_buf_dev_fops = { 
static int mem_buf_probe(struct platform_device *pdev)

{

	int ret;

	struct device *dev = &pdev->dev;

	struct device *class_dev;



	if (of_property_match_string(dev->of_node, "qcom,mem-buf-capabilities",

				     "supplier") >= 0) {

		mem_buf_capability = MEM_BUF_CAP_SUPPLIER;

	} else if (of_property_match_string(dev->of_node,

					    "qcom,mem-buf-capabilities",

					    "consumer") >= 0) {

		mem_buf_capability = MEM_BUF_CAP_CONSUMER;

	} else if (of_property_match_string(dev->of_node,

					    "qcom,mem-buf-capabilities",

					    "dual") >= 0) {

		mem_buf_capability = MEM_BUF_CAP_DUAL;

	} else {

		dev_err(dev, "Transfer direction property not present or not valid\n");

		return -EINVAL;

	}



	mem_buf_msgq_recv_thr = kthread_create(mem_buf_msgq_recv_fn, NULL,

					       "mem_buf_rcvr");

	if (IS_ERR(mem_buf_msgq_recv_thr)) {

		dev_err(&pdev->dev,

			"Failed to create msgq receiver thread rc: %d\n",

		dev_err(dev, "Failed to create msgq receiver thread rc: %d\n",

			PTR_ERR(mem_buf_msgq_recv_thr));

		return PTR_ERR(mem_buf_msgq_recv_thr);

	}
@@ -1560,7 +1589,7 @@ static int mem_buf_probe(struct platform_device *pdev) 
	if (IS_ERR(mem_buf_hh_msgq_hdl)) {

		ret = PTR_ERR(mem_buf_hh_msgq_hdl);

		if (ret != EPROBE_DEFER)

			dev_err(&pdev->dev,

			dev_err(dev,

				"Message queue registration failed: rc: %d\n",

				ret);

		goto err_msgq_register;
@@ -1571,7 +1600,7 @@ static int mem_buf_probe(struct platform_device *pdev) 
	if (ret < 0)

		goto err_cdev_add;



	mem_buf_dev = &pdev->dev;

	mem_buf_dev = dev;

	class_dev = device_create(mem_buf_class, NULL, mem_buf_dev_no, NULL,

				  "membuf");

	if (IS_ERR(class_dev)) {