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soc: qcom: mem-buf: Add support for restricting memory transfers

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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: Isaac J. Manjarres <isaacm@codeaurora.org>
This commit is contained in:
Isaac J. Manjarres 2020-03-20 18:38:47 -07:00
commit 27aa4d224b
1 changed files with 36 additions and 7 deletions
Download patch file Download diff file Expand all files Collapse all files

43
drivers/soc/qcom/mem-buf.c
View file

@ -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)) {