netdev - Re: [PATCH v2 02/15] cxl: add function for type2 cxl regs setup

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5d8f8771-8e43-6559-c510-0b8b26171c05@amd.com>
Date: Wed, 14 Aug 2024 08:56:35 +0100
From: Alejandro Lucero Palau <alucerop@....com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>,
 alejandro.lucero-palau@....com
Cc: linux-cxl@...r.kernel.org, netdev@...r.kernel.org,
 dan.j.williams@...el.com, martin.habets@...inx.com, edward.cree@....com,
 davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
 edumazet@...gle.com, richard.hughes@....com
Subject: Re: [PATCH v2 02/15] cxl: add function for type2 cxl regs setup


On 8/4/24 18:15, Jonathan Cameron wrote:
> On Mon, 15 Jul 2024 18:28:22 +0100
> alejandro.lucero-palau@....com wrote:
>
>> From: Alejandro Lucero <alucerop@....com>
>>
>> Create a new function for a type2 device initialising the opaque
>> cxl_dev_state struct regarding cxl regs setup and mapping.
>>
>> Signed-off-by: Alejandro Lucero <alucerop@....com>
>> ---
>>   drivers/cxl/pci.c                  | 28 ++++++++++++++++++++++++++++
>>   drivers/net/ethernet/sfc/efx_cxl.c |  3 +++
>>   include/linux/cxl_accel_mem.h      |  1 +
>>   3 files changed, 32 insertions(+)
>>
>> diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c
>> index e53646e9f2fb..b34d6259faf4 100644
>> --- a/drivers/cxl/pci.c
>> +++ b/drivers/cxl/pci.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/pci.h>
>>   #include <linux/aer.h>
>>   #include <linux/io.h>
>> +#include <linux/cxl_accel_mem.h>
>>   #include "cxlmem.h"
>>   #include "cxlpci.h"
>>   #include "cxl.h"
>> @@ -521,6 +522,33 @@ static int cxl_pci_setup_regs(struct pci_dev *pdev, enum cxl_regloc_type type,
>>   	return cxl_setup_regs(map);
>>   }
>>   
>> +int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds)
>> +{
>> +	struct cxl_register_map map;
>> +	int rc;
>> +
>> +	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
>> +	if (rc)
>> +		return rc;
>> +
>> +	rc = cxl_map_device_regs(&map, &cxlds->regs.device_regs);
>> +	if (rc)
>> +		return rc;
>> +
>> +	rc = cxl_pci_setup_regs(pdev, CXL_REGLOC_RBI_COMPONENT,
>> +				&cxlds->reg_map);
>> +	if (rc)
>> +		dev_warn(&pdev->dev, "No component registers (%d)\n", rc);
> Not fatal?  If we think it will happen on real devices, then dev_warn
> is too strong.


This is more complex than what it seems, and it is not properly handled 
with the current code.

I will cover it in another patch in more detail, but the fact is those 
calls to cxl_pci_setup_regs need to be handled better, because Type2 has 
some of these registers as optional.


>> +
>> +	rc = cxl_map_component_regs(&cxlds->reg_map, &cxlds->regs.component,
>> +				    BIT(CXL_CM_CAP_CAP_ID_RAS));
>> +	if (rc)
>> +		dev_dbg(&pdev->dev, "Failed to map RAS capability.\n");
> pci_err() or similar would make sense here as we have asked for something
> that isn't happening. Specification says this is mandatory so
> definitely smells like a fatal error to me.
>
>
>> +
>> +	return rc;
>> +}
>> +EXPORT_SYMBOL_NS_GPL(cxl_pci_accel_setup_regs, CXL);
>> +
>>   static int cxl_pci_ras_unmask(struct pci_dev *pdev)
>>   {
>>   	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
>> diff --git a/drivers/net/ethernet/sfc/efx_cxl.c b/drivers/net/ethernet/sfc/efx_cxl.c
>> index 4554dd7cca76..10c4fb915278 100644
>> --- a/drivers/net/ethernet/sfc/efx_cxl.c
>> +++ b/drivers/net/ethernet/sfc/efx_cxl.c
>> @@ -47,6 +47,9 @@ void efx_cxl_init(struct efx_nic *efx)
>>   
>>   	res = DEFINE_RES_MEM_NAMED(0, EFX_CTPIO_BUFFER_SIZE, "ram");
>>   	cxl_accel_set_resource(cxl->cxlds, res, CXL_ACCEL_RES_RAM);
>> +
>> +	if (cxl_pci_accel_setup_regs(pci_dev, cxl->cxlds))
>> +		pci_info(pci_dev, "CXL accel setup regs failed");
> Handle errors fully. That is report them  up to the caller.
>
>>   }
>>   
>>   
>> diff --git a/include/linux/cxl_accel_mem.h b/include/linux/cxl_accel_mem.h
>> index daf46d41f59c..ca7af4a9cefc 100644
>> --- a/include/linux/cxl_accel_mem.h
>> +++ b/include/linux/cxl_accel_mem.h
>> @@ -19,4 +19,5 @@ void cxl_accel_set_dvsec(cxl_accel_state *cxlds, u16 dvsec);
>>   void cxl_accel_set_serial(cxl_accel_state *cxlds, u64 serial);
>>   void cxl_accel_set_resource(struct cxl_dev_state *cxlds, struct resource res,
>>   			    enum accel_resource);
>> +int cxl_pci_accel_setup_regs(struct pci_dev *pdev, struct cxl_dev_state *cxlds);
>>   #endif