Re: [PATCH v5 13/27] cxl: prepare memdev creation for type2

[Dave Jiang <dave.jiang@intel.com>]

On 11/19/24 1:06 PM, Zhi Wang wrote:
> On Tue, 19 Nov 2024 11:24:44 -0700
> Dave Jiang <dave.jiang@intel.com> wrote:
> 
>>
>>
>> On 11/18/24 9:44 AM, alejandro.lucero-palau@amd.com wrote:
>>> From: Alejandro Lucero <alucerop@amd.com>
>>>
>>> Current cxl core is relying on a CXL_DEVTYPE_CLASSMEM type device
>>> when creating a memdev leading to problems when obtaining
>>> cxl_memdev_state references from a CXL_DEVTYPE_DEVMEM type. This
>>> last device type is managed by a specific vendor driver and does
>>> not need same sysfs files since not userspace intervention is
>>> expected.
>>>
>>> Create a new cxl_mem device type with no attributes for Type2.
>>>
>>> Avoid debugfs files relying on existence of clx_memdev_state.
>>>
>>> Make devm_cxl_add_memdev accesible from a accel driver.
>>>
>>> Signed-off-by: Alejandro Lucero <alucerop@amd.com>
>>> ---
>>>  drivers/cxl/core/cdat.c   |  3 +++
>>>  drivers/cxl/core/memdev.c | 15 +++++++++++++--
>>>  drivers/cxl/core/region.c |  3 ++-
>>>  drivers/cxl/mem.c         | 25 +++++++++++++++++++------
>>>  include/cxl/cxl.h         |  2 ++
>>>  5 files changed, 39 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/cxl/core/cdat.c b/drivers/cxl/core/cdat.c
>>> index e9cd7939c407..192cff18ea25 100644
>>> --- a/drivers/cxl/core/cdat.c
>>> +++ b/drivers/cxl/core/cdat.c
>>> @@ -577,6 +577,9 @@ static struct cxl_dpa_perf
>>> *cxled_get_dpa_perf(struct cxl_endpoint_decoder *cxle struct
>>> cxl_memdev_state *mds = to_cxl_memdev_state(cxlmd->cxlds); struct
>>> cxl_dpa_perf *perf; 
>>> +	if (!mds)
>>> +		return ERR_PTR(-EINVAL);
>>> +
>>>  	switch (mode) {
>>>  	case CXL_DECODER_RAM:
>>>  		perf = &mds->ram_perf;
>>> diff --git a/drivers/cxl/core/memdev.c b/drivers/cxl/core/memdev.c
>>> index d746c8a1021c..df31eea0c06b 100644
>>> --- a/drivers/cxl/core/memdev.c
>>> +++ b/drivers/cxl/core/memdev.c
>>> @@ -547,9 +547,17 @@ static const struct device_type
>>> cxl_memdev_type = { .groups = cxl_memdev_attribute_groups,
>>>  };
>>>  
>>> +static const struct device_type cxl_accel_memdev_type = {
>>> +	.name = "cxl_memdev",
>>> +	.release = cxl_memdev_release,
>>> +	.devnode = cxl_memdev_devnode,
>>> +};
>>> +
>>>  bool is_cxl_memdev(const struct device *dev)
>>>  {
>>> -	return dev->type == &cxl_memdev_type;
>>> +	return (dev->type == &cxl_memdev_type ||
>>> +		dev->type == &cxl_accel_memdev_type);
>>> +
>>>  }
>>>  EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, CXL);
>>
>> Does type2 device also exports a CDAT?
>>
> 
> Yes. Type2 can also export a CDAT.

Thanks! Probably should have the split out helpers regardless.

> 
>> I'm also wondering if we should have distinctive helpers:
>> is_cxl_type3_memdev()
>> is_cxl_type2_memdev()
>>
>> and is_cxl_memdev() is just calling those two helpers above. 
>>
>> And if no CDAT is exported, we should change the is_cxl_memdev() to
>> is_cxl_type3_memdev() in read_cdat_data(). 
>>
>> DJ
>>
>>>  
>>> @@ -660,7 +668,10 @@ static struct cxl_memdev
>>> *cxl_memdev_alloc(struct cxl_dev_state *cxlds, dev->parent =
>>> cxlds->dev; dev->bus = &cxl_bus_type;
>>>  	dev->devt = MKDEV(cxl_mem_major, cxlmd->id);
>>> -	dev->type = &cxl_memdev_type;
>>> +	if (cxlds->type == CXL_DEVTYPE_DEVMEM)
>>> +		dev->type = &cxl_accel_memdev_type;
>>> +	else
>>> +		dev->type = &cxl_memdev_type;
>>>  	device_set_pm_not_required(dev);
>>>  	INIT_WORK(&cxlmd->detach_work, detach_memdev);
>>>  
>>> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
>>> index dff618c708dc..622e3bb2e04b 100644
>>> --- a/drivers/cxl/core/region.c
>>> +++ b/drivers/cxl/core/region.c
>>> @@ -1948,7 +1948,8 @@ static int cxl_region_attach(struct
>>> cxl_region *cxlr, return -EINVAL;
>>>  	}
>>>  
>>> -	cxl_region_perf_data_calculate(cxlr, cxled);
>>> +	if (cxlr->type == CXL_DECODER_HOSTONLYMEM)
>>> +		cxl_region_perf_data_calculate(cxlr, cxled);
>>>  
>>>  	if (test_bit(CXL_REGION_F_AUTO, &cxlr->flags)) {
>>>  		int i;
>>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
>>> index a9fd5cd5a0d2..cb771bf196cd 100644
>>> --- a/drivers/cxl/mem.c
>>> +++ b/drivers/cxl/mem.c
>>> @@ -130,12 +130,18 @@ static int cxl_mem_probe(struct device *dev)
>>>  	dentry = cxl_debugfs_create_dir(dev_name(dev));
>>>  	debugfs_create_devm_seqfile(dev, "dpamem", dentry,
>>> cxl_mem_dpa_show); 
>>> -	if (test_bit(CXL_POISON_ENABLED_INJECT,
>>> mds->poison.enabled_cmds))
>>> -		debugfs_create_file("inject_poison", 0200, dentry,
>>> cxlmd,
>>> -				    &cxl_poison_inject_fops);
>>> -	if (test_bit(CXL_POISON_ENABLED_CLEAR,
>>> mds->poison.enabled_cmds))
>>> -		debugfs_create_file("clear_poison", 0200, dentry,
>>> cxlmd,
>>> -				    &cxl_poison_clear_fops);
>>> +	/*
>>> +	 * Avoid poison debugfs files for Type2 devices as they
>>> rely on
>>> +	 * cxl_memdev_state.
>>> +	 */
>>> +	if (mds) {
>>> +		if (test_bit(CXL_POISON_ENABLED_INJECT,
>>> mds->poison.enabled_cmds))
>>> +			debugfs_create_file("inject_poison", 0200,
>>> dentry, cxlmd,
>>> +
>>> &cxl_poison_inject_fops);
>>> +		if (test_bit(CXL_POISON_ENABLED_CLEAR,
>>> mds->poison.enabled_cmds))
>>> +			debugfs_create_file("clear_poison", 0200,
>>> dentry, cxlmd,
>>> +
>>> &cxl_poison_clear_fops);
>>> +	}
>>>  
>>>  	rc = devm_add_action_or_reset(dev, remove_debugfs, dentry);
>>>  	if (rc)
>>> @@ -219,6 +225,13 @@ static umode_t cxl_mem_visible(struct kobject
>>> *kobj, struct attribute *a, int n) struct cxl_memdev *cxlmd =
>>> to_cxl_memdev(dev); struct cxl_memdev_state *mds =
>>> to_cxl_memdev_state(cxlmd->cxlds); 
>>> +	/*
>>> +	 * Avoid poison sysfs files for Type2 devices as they rely
>>> on
>>> +	 * cxl_memdev_state.
>>> +	 */
>>> +	if (!mds)
>>> +		return 0;
>>> +
>>>  	if (a == &dev_attr_trigger_poison_list.attr)
>>>  		if (!test_bit(CXL_POISON_ENABLED_LIST,
>>>  			      mds->poison.enabled_cmds))
>>> diff --git a/include/cxl/cxl.h b/include/cxl/cxl.h
>>> index 6033ce84b3d3..5608ed0f5f15 100644
>>> --- a/include/cxl/cxl.h
>>> +++ b/include/cxl/cxl.h
>>> @@ -57,4 +57,6 @@ int cxl_pci_accel_setup_regs(struct pci_dev
>>> *pdev, struct cxl_dev_state *cxlds); int
>>> cxl_request_resource(struct cxl_dev_state *cxlds, enum cxl_resource
>>> type); int cxl_release_resource(struct cxl_dev_state *cxlds, enum
>>> cxl_resource type); void cxl_set_media_ready(struct cxl_dev_state
>>> *cxlds); +struct cxl_memdev *devm_cxl_add_memdev(struct device
>>> *host,
>>> +				       struct cxl_dev_state
>>> *cxlds); #endif
>>
>>
>