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

[Zhi Wang <zhiw@nvidia.com>]

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.

> 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
> 
>