Subject: Re: [PATCH V2 3/5] ocxl: Update the Process Element Entry

From: Frederic Barrat <[email-masked]>
Date: Mon, 23 Nov 2020 11:38:41 +0100

On 20/11/2020 18:32, Christophe Lombard wrote:
> To complete the MMIO based mechanism, the fields: PASID, bus, device and
> function of the Process Element Entry have to be filled. (See
> OpenCAPI Power Platform Architecture document)
> 
>                     Hypervisor Process Element Entry
> Word
>      0 1 .... 7  8  ...... 12  13 ..15  16.... 19  20 ........... 31
> 0                  OSL Configuration State (0:31)
> 1                  OSL Configuration State (32:63)
> 2               PASID                      |    Reserved
> 3       Bus   |   Device    |Function |        Reserved
> 4                             Reserved
> 5                             Reserved
> 6                               ....
> 
> Signed-off-by: Christophe Lombard <[email-masked]>
> ---
>   drivers/misc/ocxl/context.c       | 4 +++-
>   drivers/misc/ocxl/link.c          | 4 +++-
>   drivers/misc/ocxl/ocxl_internal.h | 4 +++-
>   drivers/scsi/cxlflash/ocxl_hw.c   | 6 ++++--
>   include/misc/ocxl.h               | 2 +-
>   5 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/misc/ocxl/context.c b/drivers/misc/ocxl/context.c
> index c21f65a5c762..9eb0d93b01c6 100644
> --- a/drivers/misc/ocxl/context.c
> +++ b/drivers/misc/ocxl/context.c
> @@ -70,6 +70,7 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm)
>   {
>   	int rc;
>   	unsigned long pidr = 0;
> +	struct pci_dev *dev;
> 
>   	// Locks both status & tidr
>   	mutex_lock(&ctx->status_mutex);
> @@ -81,8 +82,9 @@ int ocxl_context_attach(struct ocxl_context *ctx, u64 amr, struct mm_struct *mm)
>   	if (mm)
>   		pidr = mm->context.id;
> 
> +	dev = to_pci_dev(ctx->afu->fn->dev.parent);
>   	rc = ocxl_link_add_pe(ctx->afu->fn->link, ctx->pasid, pidr, ctx->tidr,
> -			      amr, mm, xsl_fault_error, ctx);
> +			      amr, pci_dev_id(dev), mm, xsl_fault_error, ctx);
>   	if (rc)
>   		goto out;
> 
> diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c
> index fd73d3bc0eb6..20444db8a2bb 100644
> --- a/drivers/misc/ocxl/link.c
> +++ b/drivers/misc/ocxl/link.c
> @@ -494,7 +494,7 @@ static u64 calculate_cfg_state(bool kernel)
>   }
> 
>   int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
> -		u64 amr, struct mm_struct *mm,
> +		u64 amr, u64 bdf, struct mm_struct *mm,

bdf could/should be a u16, since that's per the PCI spec.

   Fred

>   		void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr),
>   		void *xsl_err_data)
>   {
> @@ -529,6 +529,8 @@ int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
> 
>   	memset(pe, 0, sizeof(struct ocxl_process_element));
>   	pe->config_state = cpu_to_be64(calculate_cfg_state(pidr == 0));
> +	pe->pasid = cpu_to_be32(pasid << (31 - 19));
> +	pe->bdf = cpu_to_be32(bdf << (31 - 15));
>   	pe->lpid = cpu_to_be32(mfspr(SPRN_LPID));
>   	pe->pid = cpu_to_be32(pidr);
>   	pe->tid = cpu_to_be32(tidr);
> diff --git a/drivers/misc/ocxl/ocxl_internal.h b/drivers/misc/ocxl/ocxl_internal.h
> index 0bad0a123af6..c9ce2af21d6f 100644
> --- a/drivers/misc/ocxl/ocxl_internal.h
> +++ b/drivers/misc/ocxl/ocxl_internal.h
> @@ -84,7 +84,9 @@ struct ocxl_context {
> 
>   struct ocxl_process_element {
>   	__be64 config_state;
> -	__be32 reserved1[11];
> +	__be32 pasid;
> +	__be32 bdf;
> +	__be32 reserved1[9];
>   	__be32 lpid;
>   	__be32 tid;
>   	__be32 pid;
> diff --git a/drivers/scsi/cxlflash/ocxl_hw.c b/drivers/scsi/cxlflash/ocxl_hw.c
> index e4e0d767b98e..244fc27215dc 100644
> --- a/drivers/scsi/cxlflash/ocxl_hw.c
> +++ b/drivers/scsi/cxlflash/ocxl_hw.c
> @@ -329,6 +329,7 @@ static int start_context(struct ocxlflash_context *ctx)
>   	struct ocxl_hw_afu *afu = ctx->hw_afu;
>   	struct ocxl_afu_config *acfg = &afu->acfg;
>   	void *link_token = afu->link_token;
> +	struct pci_dev *pdev = afu->pdev;
>   	struct device *dev = afu->dev;
>   	bool master = ctx->master;
>   	struct mm_struct *mm;
> @@ -360,8 +361,9 @@ static int start_context(struct ocxlflash_context *ctx)
>   		mm = current->mm;
>   	}
> 
> -	rc = ocxl_link_add_pe(link_token, ctx->pe, pid, 0, 0, mm,
> -			      ocxlflash_xsl_fault, ctx);
> +	rc = ocxl_link_add_pe(link_token, ctx->pe, pid, 0, 0,
> +			      pci_dev_id(pdev), mm, ocxlflash_xsl_fault,
> +			      ctx);
>   	if (unlikely(rc)) {
>   		dev_err(dev, "%s: ocxl_link_add_pe failed rc=%d\n",
>   			__func__, rc);
> diff --git a/include/misc/ocxl.h b/include/misc/ocxl.h
> index e013736e275d..d0f101f428dd 100644
> --- a/include/misc/ocxl.h
> +++ b/include/misc/ocxl.h
> @@ -447,7 +447,7 @@ void ocxl_link_release(struct pci_dev *dev, void *link_handle);
>    * defined
>    */
>   int ocxl_link_add_pe(void *link_handle, int pasid, u32 pidr, u32 tidr,
> -		u64 amr, struct mm_struct *mm,
> +		u64 amr, u64 bdf, struct mm_struct *mm,
>   		void (*xsl_err_cb)(void *data, u64 addr, u64 dsisr),
>   		void *xsl_err_data);
>