Re: [PATCH v1] bus/pci: add function to enable/disable PASID

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Nov 03, 2023 at 12:03:47PM -0500, Abdullah Sevincer wrote:
> This commit implements an internal api to enable
> and disable PASID for a device e.g. DLB Device.
> 
> For kernels when PASID enabled by default it breaks
> DLB functionality, hence disabling PASID is required
> for DLB to function properly.
> 
> PASID capability is not exposed to users hence offset
> can not be retrieved by rte_pci_find_ext_capability()
> api. Therefore, api implemented in this commit accepts
> an offset for PASID with an enable flag which is used
> to enable/disable PASID.

Lines in the commit log can go up to 72 characters, so you can be a bit
less strict in wrapping. :-)
The term DLB may not be familiar to everyone, so I suggest referring to it
via proper name, or refer to the device driver event/dlb.

Few other minor comments inline.
/Bruce

> 
> Signed-off-by: Abdullah Sevincer <abdullah.sevincer@intel.com>
> ---
>  drivers/bus/pci/pci_common.c  |  7 +++++++
>  drivers/bus/pci/rte_bus_pci.h | 11 +++++++++++
>  drivers/bus/pci/version.map   |  1 +
>  lib/pci/rte_pci.h             |  5 +++++
>  4 files changed, 24 insertions(+)
> 
> diff --git a/drivers/bus/pci/pci_common.c b/drivers/bus/pci/pci_common.c
> index 921d957bf6..ced072825e 100644
> --- a/drivers/bus/pci/pci_common.c
> +++ b/drivers/bus/pci/pci_common.c
> @@ -938,6 +938,13 @@ rte_pci_set_bus_master(const struct rte_pci_device *dev, bool enable)
>  	return 0;
>  }
>  
> +int
> +rte_pci_set_pasid(const struct rte_pci_device *dev, off_t offset, bool enable)
> +{
> +	uint16_t pasid = enable;
> +	return rte_pci_write_config(dev, &pasid, sizeof(pasid), offset) < 0 ? -1 : 0;
> +}
> +
>  struct rte_pci_bus rte_pci_bus = {
>  	.bus = {
>  		.scan = rte_pci_scan,
> diff --git a/drivers/bus/pci/rte_bus_pci.h b/drivers/bus/pci/rte_bus_pci.h
> index 21e234abf0..d97c8320a7 100644
> --- a/drivers/bus/pci/rte_bus_pci.h
> +++ b/drivers/bus/pci/rte_bus_pci.h
> @@ -295,6 +295,17 @@ void rte_pci_ioport_read(struct rte_pci_ioport *p,
>  void rte_pci_ioport_write(struct rte_pci_ioport *p,
>  		const void *data, size_t len, off_t offset);
>  
> +/**
> + * Enable/Disable PASID.
> + *
> + * @param offset
> + *   Offset of the PASID external capability.
> + * @param enable
> + *   Flag to enable or disable PASID.
> + */

Missing parameter "dev".

> +__rte_internal
> +int rte_pci_set_pasid(const struct rte_pci_device *dev, off_t offset, bool enable);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> diff --git a/drivers/bus/pci/version.map b/drivers/bus/pci/version.map
> index 74c5b075d5..329d386c85 100644
> --- a/drivers/bus/pci/version.map
> +++ b/drivers/bus/pci/version.map
> @@ -38,4 +38,5 @@ INTERNAL {
>  	rte_pci_get_sysfs_path;
>  	rte_pci_register;
>  	rte_pci_unregister;
> +	rte_pci_set_pasid;

Keep list in alphabetical order, so new entry goes above unregister.

>  };
> diff --git a/lib/pci/rte_pci.h b/lib/pci/rte_pci.h
> index 69e932d910..772a8d5622 100644
> --- a/lib/pci/rte_pci.h
> +++ b/lib/pci/rte_pci.h
> @@ -101,6 +101,11 @@ extern "C" {
>  #define RTE_PCI_EXT_CAP_ID_ACS		0x0d	/* Access Control Services */
>  #define RTE_PCI_EXT_CAP_ID_SRIOV	0x10	/* SR-IOV */
>  #define RTE_PCI_EXT_CAP_ID_PRI		0x13	/* Page Request Interface */
> +#define RTE_PCI_EXT_CAP_ID_PASID        0x1B    /* Process Address Space ID */
> +
> +/* Process Address Space ID */
> +#define RTE_PCI_PASID_CTRL		0x06    /* PASID control register */
> +#define RTE_PCI_PASID_CAP_OFFSET        0x148   /* PASID capability offset */
>  
>  /* Advanced Error Reporting (RTE_PCI_EXT_CAP_ID_ERR) */
>  #define RTE_PCI_ERR_UNCOR_STATUS	0x04	/* Uncorrectable Error Status */
> -- 
> 2.25.1
>