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

[Alejandro Lucero Palau <alucerop@amd.com>]

On 11/19/24 21:27, Dave Jiang wrote:
>
> 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.


Maybe, but should not we wait until that is required? I did not see the 
need for adding them with this patchset.


>>> 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
>>>