@@ -117,7 +117,9 @@ Description:
range is fixed. For decoders of devtype "cxl_decoder_switch" the
address is bounded by the decode range of the cxl_port ancestor
of the decoder's cxl_port, and dynamically updates based on the
- active memory regions in that address space.
+ active memory regions in that address space. For decoders of
+ devtype "cxl_decoder_endpoint", size is a mutable value which
+ carves our space from the physical media.
What: /sys/bus/cxl/devices/decoderX.Y/locked
Date: June, 2021
@@ -163,3 +165,12 @@ Description:
memory (type-3). The 'target_type' attribute indicates the
current setting which may dynamically change based on what
memory regions are activated in this decode hierarchy.
+
+What: /sys/bus/cxl/devices/decoderX.Y/volatile
+Date: March, 2022
+KernelVersion: v5.19
+Contact: linux-cxl@vger.kernel.org
+Description:
+ Provide a knob to set/get whether the desired media is volatile
+ or persistent. This applies only to decoders of devtype
+ "cxl_decoder_endpoint",
@@ -95,7 +95,8 @@ config CXL_MEM
If unsure say 'm'.
config CXL_PORT
- default CXL_BUS
tristate
+ default CXL_BUS
+ select DEVICE_PRIVATE
endif
@@ -4,6 +4,7 @@
#include <linux/workqueue.h>
#include <linux/genalloc.h>
#include <linux/device.h>
+#include <linux/ioport.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/slab.h>
@@ -80,7 +81,7 @@ static ssize_t start_show(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_ADMIN_RO(start);
static ssize_t size_show(struct device *dev, struct device_attribute *attr,
- char *buf)
+ char *buf)
{
struct cxl_decoder *cxld = to_cxl_decoder(dev);
@@ -93,7 +94,144 @@ static ssize_t size_show(struct device *dev, struct device_attribute *attr,
return sysfs_emit(buf, "%#llx\n", range_len(&cxld->range));
}
}
-static DEVICE_ATTR_RO(size);
+
+static struct cxl_endpoint_decoder *
+get_prev_decoder(struct cxl_endpoint_decoder *cxled)
+{
+ struct cxl_port *port = to_cxl_port(cxled->base.dev.parent);
+ struct device *cxldd;
+ char *name;
+
+ if (cxled->base.id == 0)
+ return NULL;
+
+ name = kasprintf(GFP_KERNEL, "decoder%u.%u", port->id, cxled->base.id);
+ if (!name)
+ return ERR_PTR(-ENOMEM);
+
+ cxldd = device_find_child_by_name(&port->dev, name);
+ kfree(name);
+ if (cxldd) {
+ struct cxl_decoder *cxld = to_cxl_decoder(cxldd);
+
+ if (dev_WARN_ONCE(&port->dev,
+ (cxld->flags & CXL_DECODER_F_ENABLE) == 0,
+ "%s should be enabled\n",
+ dev_name(&cxld->dev)))
+ return NULL;
+ return to_cxl_endpoint_decoder(cxld);
+ }
+
+ return NULL;
+}
+
+static ssize_t size_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct cxl_decoder *cxld = to_cxl_decoder(dev);
+ struct cxl_endpoint_decoder *cxled = to_cxl_endpoint_decoder(cxld);
+ struct cxl_port *port = to_cxl_port(cxled->base.dev.parent);
+ struct cxl_endpoint_decoder *prev = get_prev_decoder(cxled);
+ u64 size, dpa_base = 0;
+ int rc;
+
+ rc = kstrtou64(buf, 0, &size);
+ if (rc)
+ return rc;
+
+ if (size % SZ_256M)
+ return -EINVAL;
+
+ rc = mutex_lock_interruptible(&cxled->res_lock);
+ if (rc)
+ return rc;
+
+ /* No change */
+ if (range_len(&cxled->drange) == size)
+ goto out;
+
+ rc = mutex_lock_interruptible(&port->media_lock);
+ if (rc)
+ goto out;
+
+ /* Extent was previously set */
+ if (port->last_cxled == cxled) {
+ if (size == range_len(&cxled->drange)) {
+ mutex_unlock(&port->media_lock);
+ goto out;
+ }
+
+ if (!size) {
+ dev_dbg(dev,
+ "freeing previous reservation %#llx-%#llx\n",
+ cxled->drange.start, cxled->drange.end);
+ port->last_cxled = prev;
+ mutex_unlock(&port->media_lock);
+ goto out;
+ }
+ }
+
+ if (prev)
+ dpa_base = port->last_cxled->drange.end + 1;
+
+ if ((dpa_base + size) > port->capacity)
+ rc = -ENOSPC;
+ else
+ port->last_cxled = cxled;
+
+ mutex_unlock(&port->media_lock);
+ if (rc)
+ goto out;
+
+ cxled->drange = (struct range) {
+ .start = dpa_base,
+ .end = dpa_base + size - 1
+ };
+
+ dev_dbg(dev, "Allocated %#llx-%#llx from media\n", cxled->drange.start,
+ cxled->drange.end);
+
+out:
+ mutex_unlock(&cxled->res_lock);
+ return rc ? rc : len;
+}
+static DEVICE_ATTR_RW(size);
+
+static ssize_t volatile_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct cxl_decoder *cxld = to_cxl_decoder(dev);
+ struct cxl_endpoint_decoder *cxled = to_cxl_endpoint_decoder(cxld);
+
+ return sysfs_emit(buf, "%u\n", cxled->volatil);
+}
+
+static ssize_t volatile_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct cxl_decoder *cxld = to_cxl_decoder(dev);
+ struct cxl_endpoint_decoder *cxled = to_cxl_endpoint_decoder(cxld);
+ bool p;
+ int rc;
+
+ rc = kstrtobool(buf, &p);
+ if (rc)
+ return rc;
+
+ rc = mutex_lock_interruptible(&cxled->res_lock);
+ if (rc)
+ return rc;
+
+ if (range_len(&cxled->drange) > 0)
+ rc = -EBUSY;
+ mutex_unlock(&cxled->res_lock);
+ if (rc)
+ return rc;
+
+ cxled->volatil = p;
+ return len;
+}
+static DEVICE_ATTR_RW(volatile);
#define CXL_DECODER_FLAG_ATTR(name, flag) \
static ssize_t name##_show(struct device *dev, \
@@ -211,6 +349,7 @@ static const struct attribute_group *cxl_decoder_root_attribute_groups[] = {
static struct attribute *cxl_decoder_endpoint_attrs[] = {
&dev_attr_target_type.attr,
+ &dev_attr_volatile.attr,
NULL,
};
@@ -413,6 +552,7 @@ static struct cxl_port *cxl_port_alloc(struct device *uport,
ida_init(&port->decoder_ida);
INIT_LIST_HEAD(&port->dports);
INIT_LIST_HEAD(&port->endpoints);
+ mutex_init(&port->media_lock);
device_initialize(dev);
device_set_pm_not_required(dev);
@@ -1191,6 +1331,7 @@ static struct cxl_decoder *__cxl_decoder_alloc(struct cxl_port *port,
cxled = kzalloc(sizeof(*cxled), GFP_KERNEL);
if (!cxled)
return NULL;
+ mutex_init(&cxled->res_lock);
cxld = &cxled->base;
} else if (is_cxl_root(port)) {
struct cxl_root_decoder *cxlrd;
@@ -230,11 +230,15 @@ struct cxl_decoder {
* @base: Base class decoder
* @drange: Device physical address space this decoder is using
* @skip: The skip count as specified in the CXL specification.
+ * @res_lock: Synchronize device's resource usage
+ * @volatil: Configuration param. Decoder target is non-persistent mem
*/
struct cxl_endpoint_decoder {
struct cxl_decoder base;
struct range drange;
u64 skip;
+ struct mutex res_lock; /* sync access to decoder's resource */
+ bool volatil;
};
/**
@@ -321,6 +325,7 @@ struct cxl_nvdimm {
* @pmem_offset: Partition dividing volatile, [0, pmem_offset -1 ], and persistent
* [pmem_offset, capacity - 1] addresses.
* @last_cxled: Last active decoder doing decode (endpoint only)
+ * @media_lock: Synchronizes use of allocation of media (endpoint only)
*/
struct cxl_port {
struct device dev;
@@ -336,6 +341,7 @@ struct cxl_port {
u64 capacity;
u64 pmem_offset;
struct cxl_endpoint_decoder *last_cxled;
+ struct mutex media_lock; /* sync access to media allocator */
};
/**
Endpoint decoders have the decoder-unique properties of having their range being constrained by the media they're a part of, and, having a concrete need to disambiguate between volatile and persistent capacity (due to partitioning). As part of region programming, these decoders will be required to be pre-configured, ie, have the size and volatility set. Endpoint decoders must consider two different address spaces for address allocation. Sysram will need to be mapped for use of this memory if not set up in the EFI memory map. Additionally, the CXL device itself has it's own address space domain which requires allocation and management. Device address space is managed with a simple allocator and host physical address space is managed by the region driver/core. /sys/bus/cxl/devices/decoder3.0 ├── devtype ├── interleave_granularity ├── interleave_ways ├── locked ├── modalias ├── size ├── start ├── subsystem -> ../../../../../../../bus/cxl ├── target_type ├── uevent └── volatile Signed-off-by: Ben Widawsky <ben.widawsky@intel.com> --- Documentation/ABI/testing/sysfs-bus-cxl | 13 ++- drivers/cxl/Kconfig | 3 +- drivers/cxl/core/port.c | 145 +++++++++++++++++++++++- drivers/cxl/cxl.h | 6 + 4 files changed, 163 insertions(+), 4 deletions(-)