diff mbox series

[v3] cxl/core/region: check interleave capability

Message ID 20240409022621.29115-1-yaoxt.fnst@fujitsu.com
State New
Headers show
Series [v3] cxl/core/region: check interleave capability | expand

Commit Message

Yao Xingtao April 9, 2024, 2:26 a.m. UTC
Since interleave capability is not checked, a target can be attached to
region successfully even it does not support the interleave way or
interleave granularity.

When accessing the memory, unexpected behavior occurs due to converting
HPA to an error DPA:
$ numactl -m 2 ls
Segmentation fault (core dumped)

Link: https://lore.kernel.org/qemu-devel/20240327014653.26623-1-yaoxt.fnst@fujitsu.com
Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
---
 drivers/cxl/core/hdm.c    |  5 ++++
 drivers/cxl/core/region.c | 51 +++++++++++++++++++++++++++++++++++++++
 drivers/cxl/cxl.h         |  2 ++
 drivers/cxl/cxlmem.h      |  1 +
 4 files changed, 59 insertions(+)

Comments

Yao Xingtao April 17, 2024, 6:30 a.m. UTC | #1
ping

> -----Original Message-----
> From: Yao Xingtao <yaoxt.fnst@fujitsu.com>
> Sent: Tuesday, April 9, 2024 10:26 AM
> To: dave@stgolabs.net; jonathan.cameron@huawei.com; dave.jiang@intel.com;
> alison.schofield@intel.com; vishal.l.verma@intel.com; ira.weiny@intel.com;
> dan.j.williams@intel.com; jim.harris@samsung.com
> Cc: linux-cxl@vger.kernel.org; Yao, Xingtao/姚 幸涛 <yaoxt.fnst@fujitsu.com>
> Subject: [PATCH v3] cxl/core/region: check interleave capability
> 
> Since interleave capability is not checked, a target can be attached to
> region successfully even it does not support the interleave way or
> interleave granularity.
> 
> When accessing the memory, unexpected behavior occurs due to converting
> HPA to an error DPA:
> $ numactl -m 2 ls
> Segmentation fault (core dumped)
> 
> Link:
> https://lore.kernel.org/qemu-devel/20240327014653.26623-1-yaoxt.fnst@fujitsu.c
> om
> Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
> ---
>  drivers/cxl/core/hdm.c    |  5 ++++
>  drivers/cxl/core/region.c | 51
> +++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/cxl.h         |  2 ++
>  drivers/cxl/cxlmem.h      |  1 +
>  4 files changed, 59 insertions(+)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 7d97790b893d..5ac79d843a16 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -79,6 +79,11 @@ static void parse_hdm_decoder_caps(struct cxl_hdm
> *cxlhdm)
>  		cxlhdm->interleave_mask |= GENMASK(11, 8);
>  	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
>  		cxlhdm->interleave_mask |= GENMASK(14, 12);
> +	cxlhdm->iw_cap_mask = BIT(1) | BIT(2) | BIT(4) | BIT(8);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY,
> hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(3) | BIT(6) | BIT(12);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(16);
>  }
> 
>  static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 5c186e0a39b9..abc14fe1717e 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1210,6 +1210,41 @@ static int check_last_peer(struct cxl_endpoint_decoder
> *cxled,
>  	return 0;
>  }
> 
> +static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
> +{
> +	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> +	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
> +	unsigned int interleave_mask;
> +	u8 eiw;
> +	u16 eig;
> +	int rc, start_pos, stop_pos;
> +
> +	rc = ways_to_eiw(iw, &eiw);
> +	if (rc)
> +		return rc;
> +
> +	if (!(cxlhdm->iw_cap_mask & BIT(iw)))
> +		return -EOPNOTSUPP;
> +
> +	rc = granularity_to_eig(ig, &eig);
> +	if (rc)
> +		return rc;
> +
> +	if (eiw >= 8)
> +		start_pos = eiw + eig - 1;
> +	else
> +		start_pos = eiw + eig + 7;
> +	stop_pos = eig + 8;
> +	if (stop_pos > start_pos)
> +		return 0;
> +
> +	interleave_mask = GENMASK(start_pos, stop_pos);
> +	if ((interleave_mask & cxlhdm->interleave_mask) != interleave_mask)
> +		return -EOPNOTSUPP;
> +
> +	return 0;
> +}
> +
>  static int cxl_port_setup_targets(struct cxl_port *port,
>  				  struct cxl_region *cxlr,
>  				  struct cxl_endpoint_decoder *cxled)
> @@ -1360,6 +1395,14 @@ static int cxl_port_setup_targets(struct cxl_port *port,
>  			return -ENXIO;
>  		}
>  	} else {
> +		rc = check_interleave_cap(cxld, iw, ig);
I found that when the switch decoder is passthrough, this check will fail because single ported
host-bridges need not publish a decoder capability.

But I can not find a way to check the decoder is passthrough, so I decide to append
a flag called 'passthrough' to struct cxl_switch_decoder, and when a passthrough decoder is added, 
set passthrough of cxl_switch_decoder as true.

In check_interleave_cap(),  when the decoder is switch decoder and the passthrough flag is true, skip the following check.

Any ideas?

> +		if (rc) {
> +			dev_dbg(&cxlr->dev,
> +				"%s:%s iw: %d ig: %d is not supported\n",
> +				dev_name(port->uport_dev),
> +				dev_name(&port->dev), iw, ig);
> +			return rc;
> +		}
>  		cxld->interleave_ways = iw;
>  		cxld->interleave_granularity = ig;
>  		cxld->hpa_range = (struct range) {
> @@ -1796,6 +1839,14 @@ static int cxl_region_attach(struct cxl_region *cxlr,
>  	struct cxl_dport *dport;
>  	int rc = -ENXIO;
> 
> +	rc = check_interleave_cap(&cxled->cxld, p->interleave_ways,
> +				  p->interleave_granularity);
> +	if (rc) {
> +		dev_dbg(&cxlr->dev, "%s iw: %d ig: %d is not supported\n",
> +			dev_name(&cxled->cxld.dev), p->interleave_ways,
> +			p->interleave_granularity);
> +		return rc;
> +	}
>  	if (cxled->mode != cxlr->mode) {
>  		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
>  			dev_name(&cxled->cxld.dev), cxlr->mode,
> cxled->mode);
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 534e25e2f0a4..da8a487ededa 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -45,6 +45,8 @@
>  #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
>  #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
>  #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
> +#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
> +#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
>  #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
>  #define   CXL_HDM_DECODER_ENABLE BIT(1)
>  #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 20fb3b35e89e..1ec3e6285d41 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -853,6 +853,7 @@ struct cxl_hdm {
>  	unsigned int decoder_count;
>  	unsigned int target_count;
>  	unsigned int interleave_mask;
> +	unsigned int iw_cap_mask;
>  	struct cxl_port *port;
>  };
> 
> --
> 2.37.3
Jonathan Cameron April 19, 2024, 2:16 p.m. UTC | #2
On Mon,  8 Apr 2024 22:26:21 -0400
Yao Xingtao <yaoxt.fnst@fujitsu.com> wrote:

> Since interleave capability is not checked, a target can be attached to
> region successfully even it does not support the interleave way or
> interleave granularity.
> 
> When accessing the memory, unexpected behavior occurs due to converting
> HPA to an error DPA:
> $ numactl -m 2 ls
> Segmentation fault (core dumped)

I'd drop this comment - a real device should have rejected the capacity.
We don't need the kernel change log to point out the qemu emulation is buggy :)

> 
> Link: https://lore.kernel.org/qemu-devel/20240327014653.26623-1-yaoxt.fnst@fujitsu.com
> Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
A few minor things mostly around naming.

Jonathan

> ---
>  drivers/cxl/core/hdm.c    |  5 ++++
>  drivers/cxl/core/region.c | 51 +++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/cxl.h         |  2 ++
>  drivers/cxl/cxlmem.h      |  1 +
>  4 files changed, 59 insertions(+)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 7d97790b893d..5ac79d843a16 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -79,6 +79,11 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
>  		cxlhdm->interleave_mask |= GENMASK(11, 8);
>  	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
>  		cxlhdm->interleave_mask |= GENMASK(14, 12);
> +	cxlhdm->iw_cap_mask = BIT(1) | BIT(2) | BIT(4) | BIT(8);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY, hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(3) | BIT(6) | BIT(12);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(16);
>  }
>  
>  static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 5c186e0a39b9..abc14fe1717e 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1210,6 +1210,41 @@ static int check_last_peer(struct cxl_endpoint_decoder *cxled,
>  	return 0;
>  }
>  
> +static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
> +{
> +	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> +	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
> +	unsigned int interleave_mask;
> +	u8 eiw;
> +	u16 eig;
> +	int rc, start_pos, stop_pos;
> +
> +	rc = ways_to_eiw(iw, &eiw);
> +	if (rc)
> +		return rc;
> +
> +	if (!(cxlhdm->iw_cap_mask & BIT(iw)))
> +		return -EOPNOTSUPP;
> +
> +	rc = granularity_to_eig(ig, &eig);
> +	if (rc)
> +		return rc;
> +
> +	if (eiw >= 8)
> +		start_pos = eiw + eig - 1;
> +	else
> +		start_pos = eiw + eig + 7;
> +	stop_pos = eig + 8;

I'd like to see a comment with a specification reference for this
maths.  Probably the implementation note which oddly ended up in 
8.2.20.13 Decoder Protection. in r3.1

> +	if (stop_pos > start_pos)
> +		return 0;
> +
> +	interleave_mask = GENMASK(start_pos, stop_pos);

I'd use high_pos and low_pos to avoid ambiguity around start
and stop and which is which (I thought this was backwards at first glance)

> +	if ((interleave_mask & cxlhdm->interleave_mask) != interleave_mask)
This is effectively checking for one not contained in the other. Can use
the perhaps simpler check of is the interleave_mask no overlapping with everything
outside of cxlhdm->interleave_mask

	if (interleave_mask & ~cxlhd->interleave_mask)
I think...

> +		return -EOPNOTSUPP;
> +
> +	return 0;
> +}
> +
>  static int cxl_port_setup_targets(struct cxl_port *port,
>  				  struct cxl_region *cxlr,
>  				  struct cxl_endpoint_decoder *cxled)
> @@ -1360,6 +1395,14 @@ static int cxl_port_setup_targets(struct cxl_port *port,
>  			return -ENXIO;
>  		}
>  	} else {
> +		rc = check_interleave_cap(cxld, iw, ig);
> +		if (rc) {
> +			dev_dbg(&cxlr->dev,
> +				"%s:%s iw: %d ig: %d is not supported\n",
> +				dev_name(port->uport_dev),
> +				dev_name(&port->dev), iw, ig);
> +			return rc;
> +		}
>  		cxld->interleave_ways = iw;
>  		cxld->interleave_granularity = ig;
>  		cxld->hpa_range = (struct range) {
> @@ -1796,6 +1839,14 @@ static int cxl_region_attach(struct cxl_region *cxlr,
>  	struct cxl_dport *dport;
>  	int rc = -ENXIO;
>  
> +	rc = check_interleave_cap(&cxled->cxld, p->interleave_ways,
> +				  p->interleave_granularity);
> +	if (rc) {
> +		dev_dbg(&cxlr->dev, "%s iw: %d ig: %d is not supported\n",
> +			dev_name(&cxled->cxld.dev), p->interleave_ways,
> +			p->interleave_granularity);
> +		return rc;
> +	}
>  	if (cxled->mode != cxlr->mode) {
>  		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
>  			dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 534e25e2f0a4..da8a487ededa 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -45,6 +45,8 @@
>  #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
>  #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
>  #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
> +#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
> +#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
>  #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
>  #define   CXL_HDM_DECODER_ENABLE BIT(1)
>  #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 20fb3b35e89e..1ec3e6285d41 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -853,6 +853,7 @@ struct cxl_hdm {
>  	unsigned int decoder_count;
>  	unsigned int target_count;
>  	unsigned int interleave_mask;
> +	unsigned int iw_cap_mask;
>  	struct cxl_port *port;
>  };
>
fan April 19, 2024, 5:01 p.m. UTC | #3
On Mon, Apr 08, 2024 at 10:26:21PM -0400, Yao Xingtao wrote:
> Since interleave capability is not checked, a target can be attached to
> region successfully even it does not support the interleave way or
> interleave granularity.
> 
> When accessing the memory, unexpected behavior occurs due to converting
> HPA to an error DPA:
> $ numactl -m 2 ls
> Segmentation fault (core dumped)

The commit comments only explain what the issue is before the change,
maybe add some sentence to describe the change?

Fan

> 
> Link: https://lore.kernel.org/qemu-devel/20240327014653.26623-1-yaoxt.fnst@fujitsu.com
> Signed-off-by: Yao Xingtao <yaoxt.fnst@fujitsu.com>
> ---
>  drivers/cxl/core/hdm.c    |  5 ++++
>  drivers/cxl/core/region.c | 51 +++++++++++++++++++++++++++++++++++++++
>  drivers/cxl/cxl.h         |  2 ++
>  drivers/cxl/cxlmem.h      |  1 +
>  4 files changed, 59 insertions(+)
> 
> diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
> index 7d97790b893d..5ac79d843a16 100644
> --- a/drivers/cxl/core/hdm.c
> +++ b/drivers/cxl/core/hdm.c
> @@ -79,6 +79,11 @@ static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
>  		cxlhdm->interleave_mask |= GENMASK(11, 8);
>  	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
>  		cxlhdm->interleave_mask |= GENMASK(14, 12);
> +	cxlhdm->iw_cap_mask = BIT(1) | BIT(2) | BIT(4) | BIT(8);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY, hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(3) | BIT(6) | BIT(12);
> +	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
> +		cxlhdm->iw_cap_mask |= BIT(16);
>  }
>  
>  static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 5c186e0a39b9..abc14fe1717e 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -1210,6 +1210,41 @@ static int check_last_peer(struct cxl_endpoint_decoder *cxled,
>  	return 0;
>  }
>  
> +static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
> +{
> +	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
> +	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
> +	unsigned int interleave_mask;
> +	u8 eiw;
> +	u16 eig;
> +	int rc, start_pos, stop_pos;
> +
> +	rc = ways_to_eiw(iw, &eiw);
> +	if (rc)
> +		return rc;
> +
> +	if (!(cxlhdm->iw_cap_mask & BIT(iw)))
> +		return -EOPNOTSUPP;
> +
> +	rc = granularity_to_eig(ig, &eig);
> +	if (rc)
> +		return rc;
> +
> +	if (eiw >= 8)
> +		start_pos = eiw + eig - 1;
> +	else
> +		start_pos = eiw + eig + 7;
> +	stop_pos = eig + 8;
> +	if (stop_pos > start_pos)
> +		return 0;
> +
> +	interleave_mask = GENMASK(start_pos, stop_pos);
> +	if ((interleave_mask & cxlhdm->interleave_mask) != interleave_mask)
> +		return -EOPNOTSUPP;
> +
> +	return 0;
> +}
> +
>  static int cxl_port_setup_targets(struct cxl_port *port,
>  				  struct cxl_region *cxlr,
>  				  struct cxl_endpoint_decoder *cxled)
> @@ -1360,6 +1395,14 @@ static int cxl_port_setup_targets(struct cxl_port *port,
>  			return -ENXIO;
>  		}
>  	} else {
> +		rc = check_interleave_cap(cxld, iw, ig);
> +		if (rc) {
> +			dev_dbg(&cxlr->dev,
> +				"%s:%s iw: %d ig: %d is not supported\n",
> +				dev_name(port->uport_dev),
> +				dev_name(&port->dev), iw, ig);
> +			return rc;
> +		}
>  		cxld->interleave_ways = iw;
>  		cxld->interleave_granularity = ig;
>  		cxld->hpa_range = (struct range) {
> @@ -1796,6 +1839,14 @@ static int cxl_region_attach(struct cxl_region *cxlr,
>  	struct cxl_dport *dport;
>  	int rc = -ENXIO;
>  
> +	rc = check_interleave_cap(&cxled->cxld, p->interleave_ways,
> +				  p->interleave_granularity);
> +	if (rc) {
> +		dev_dbg(&cxlr->dev, "%s iw: %d ig: %d is not supported\n",
> +			dev_name(&cxled->cxld.dev), p->interleave_ways,
> +			p->interleave_granularity);
> +		return rc;
> +	}
>  	if (cxled->mode != cxlr->mode) {
>  		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
>  			dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 534e25e2f0a4..da8a487ededa 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -45,6 +45,8 @@
>  #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
>  #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
>  #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
> +#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
> +#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
>  #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
>  #define   CXL_HDM_DECODER_ENABLE BIT(1)
>  #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
> diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
> index 20fb3b35e89e..1ec3e6285d41 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -853,6 +853,7 @@ struct cxl_hdm {
>  	unsigned int decoder_count;
>  	unsigned int target_count;
>  	unsigned int interleave_mask;
> +	unsigned int iw_cap_mask;
>  	struct cxl_port *port;
>  };
>  
> -- 
> 2.37.3
>
diff mbox series

Patch

diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c
index 7d97790b893d..5ac79d843a16 100644
--- a/drivers/cxl/core/hdm.c
+++ b/drivers/cxl/core/hdm.c
@@ -79,6 +79,11 @@  static void parse_hdm_decoder_caps(struct cxl_hdm *cxlhdm)
 		cxlhdm->interleave_mask |= GENMASK(11, 8);
 	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_14_12, hdm_cap))
 		cxlhdm->interleave_mask |= GENMASK(14, 12);
+	cxlhdm->iw_cap_mask = BIT(1) | BIT(2) | BIT(4) | BIT(8);
+	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY, hdm_cap))
+		cxlhdm->iw_cap_mask |= BIT(3) | BIT(6) | BIT(12);
+	if (FIELD_GET(CXL_HDM_DECODER_INTERLEAVE_16_WAY, hdm_cap))
+		cxlhdm->iw_cap_mask |= BIT(16);
 }
 
 static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 5c186e0a39b9..abc14fe1717e 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -1210,6 +1210,41 @@  static int check_last_peer(struct cxl_endpoint_decoder *cxled,
 	return 0;
 }
 
+static int check_interleave_cap(struct cxl_decoder *cxld, int iw, int ig)
+{
+	struct cxl_port *port = to_cxl_port(cxld->dev.parent);
+	struct cxl_hdm *cxlhdm = dev_get_drvdata(&port->dev);
+	unsigned int interleave_mask;
+	u8 eiw;
+	u16 eig;
+	int rc, start_pos, stop_pos;
+
+	rc = ways_to_eiw(iw, &eiw);
+	if (rc)
+		return rc;
+
+	if (!(cxlhdm->iw_cap_mask & BIT(iw)))
+		return -EOPNOTSUPP;
+
+	rc = granularity_to_eig(ig, &eig);
+	if (rc)
+		return rc;
+
+	if (eiw >= 8)
+		start_pos = eiw + eig - 1;
+	else
+		start_pos = eiw + eig + 7;
+	stop_pos = eig + 8;
+	if (stop_pos > start_pos)
+		return 0;
+
+	interleave_mask = GENMASK(start_pos, stop_pos);
+	if ((interleave_mask & cxlhdm->interleave_mask) != interleave_mask)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
 static int cxl_port_setup_targets(struct cxl_port *port,
 				  struct cxl_region *cxlr,
 				  struct cxl_endpoint_decoder *cxled)
@@ -1360,6 +1395,14 @@  static int cxl_port_setup_targets(struct cxl_port *port,
 			return -ENXIO;
 		}
 	} else {
+		rc = check_interleave_cap(cxld, iw, ig);
+		if (rc) {
+			dev_dbg(&cxlr->dev,
+				"%s:%s iw: %d ig: %d is not supported\n",
+				dev_name(port->uport_dev),
+				dev_name(&port->dev), iw, ig);
+			return rc;
+		}
 		cxld->interleave_ways = iw;
 		cxld->interleave_granularity = ig;
 		cxld->hpa_range = (struct range) {
@@ -1796,6 +1839,14 @@  static int cxl_region_attach(struct cxl_region *cxlr,
 	struct cxl_dport *dport;
 	int rc = -ENXIO;
 
+	rc = check_interleave_cap(&cxled->cxld, p->interleave_ways,
+				  p->interleave_granularity);
+	if (rc) {
+		dev_dbg(&cxlr->dev, "%s iw: %d ig: %d is not supported\n",
+			dev_name(&cxled->cxld.dev), p->interleave_ways,
+			p->interleave_granularity);
+		return rc;
+	}
 	if (cxled->mode != cxlr->mode) {
 		dev_dbg(&cxlr->dev, "%s region mode: %d mismatch: %d\n",
 			dev_name(&cxled->cxld.dev), cxlr->mode, cxled->mode);
diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
index 534e25e2f0a4..da8a487ededa 100644
--- a/drivers/cxl/cxl.h
+++ b/drivers/cxl/cxl.h
@@ -45,6 +45,8 @@ 
 #define   CXL_HDM_DECODER_TARGET_COUNT_MASK GENMASK(7, 4)
 #define   CXL_HDM_DECODER_INTERLEAVE_11_8 BIT(8)
 #define   CXL_HDM_DECODER_INTERLEAVE_14_12 BIT(9)
+#define   CXL_HDM_DECODER_INTERLEAVE_3_6_12_WAY BIT(11)
+#define   CXL_HDM_DECODER_INTERLEAVE_16_WAY BIT(12)
 #define CXL_HDM_DECODER_CTRL_OFFSET 0x4
 #define   CXL_HDM_DECODER_ENABLE BIT(1)
 #define CXL_HDM_DECODER0_BASE_LOW_OFFSET(i) (0x20 * (i) + 0x10)
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index 20fb3b35e89e..1ec3e6285d41 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -853,6 +853,7 @@  struct cxl_hdm {
 	unsigned int decoder_count;
 	unsigned int target_count;
 	unsigned int interleave_mask;
+	unsigned int iw_cap_mask;
 	struct cxl_port *port;
 };