[PATCH v3 1/2] platform/x86/intel/pmt: allow user offset for PMT callbacks

[Ilpo Järvinen]

On Thu, 14 Nov 2024, Michael J. Ruhl wrote:

> Usage of the telem sysfs file allows for partial reads at an offset.
> 
> The current callback method returns the buffer starting from offset 0
> only.
> 
> Include the requested offset in the callback.
> Update the necessary address calculations with the offset.
> 
> Note: offset addition is moved from the caller to the local usage.  For
> non-callback usage this is unchanged behavior.
> 
> Fixes: e92affc74cd8 ("platform/x86/intel/vsec: Add PMT read callbacks")
> Reviewed-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl at intel.com>

Hi,

I've applied this patch 1 into pdx86/review-ilpo where it will migrate 
into pdx86/for-next in this cycle once lkp has done its magic.

-- 
 i.

> ---
>  drivers/platform/x86/intel/pmt/class.c     | 8 +++++---
>  drivers/platform/x86/intel/pmt/class.h     | 2 +-
>  drivers/platform/x86/intel/pmt/telemetry.c | 2 +-
>  include/linux/intel_vsec.h                 | 3 ++-
>  4 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/platform/x86/intel/pmt/class.c b/drivers/platform/x86/intel/pmt/class.c
> index c04bb7f97a4d..c3ca2ac91b05 100644
> --- a/drivers/platform/x86/intel/pmt/class.c
> +++ b/drivers/platform/x86/intel/pmt/class.c
> @@ -59,10 +59,12 @@ pmt_memcpy64_fromio(void *to, const u64 __iomem *from, size_t count)
>  }
>  
>  int pmt_telem_read_mmio(struct pci_dev *pdev, struct pmt_callbacks *cb, u32 guid, void *buf,
> -			void __iomem *addr, u32 count)
> +			void __iomem *addr, loff_t off, u32 count)
>  {
>  	if (cb && cb->read_telem)
> -		return cb->read_telem(pdev, guid, buf, count);
> +		return cb->read_telem(pdev, guid, buf, off, count);
> +
> +	addr += off;
>  
>  	if (guid == GUID_SPR_PUNIT)
>  		/* PUNIT on SPR only supports aligned 64-bit read */
> @@ -96,7 +98,7 @@ intel_pmt_read(struct file *filp, struct kobject *kobj,
>  		count = entry->size - off;
>  
>  	count = pmt_telem_read_mmio(entry->ep->pcidev, entry->cb, entry->header.guid, buf,
> -				    entry->base + off, count);
> +				    entry->base, off, count);
>  
>  	return count;
>  }
> diff --git a/drivers/platform/x86/intel/pmt/class.h b/drivers/platform/x86/intel/pmt/class.h
> index a267ac964423..b2006d57779d 100644
> --- a/drivers/platform/x86/intel/pmt/class.h
> +++ b/drivers/platform/x86/intel/pmt/class.h
> @@ -62,7 +62,7 @@ struct intel_pmt_namespace {
>  };
>  
>  int pmt_telem_read_mmio(struct pci_dev *pdev, struct pmt_callbacks *cb, u32 guid, void *buf,
> -			void __iomem *addr, u32 count);
> +			void __iomem *addr, loff_t off, u32 count);
>  bool intel_pmt_is_early_client_hw(struct device *dev);
>  int intel_pmt_dev_create(struct intel_pmt_entry *entry,
>  			 struct intel_pmt_namespace *ns,
> diff --git a/drivers/platform/x86/intel/pmt/telemetry.c b/drivers/platform/x86/intel/pmt/telemetry.c
> index c9feac859e57..0cea617c6c2e 100644
> --- a/drivers/platform/x86/intel/pmt/telemetry.c
> +++ b/drivers/platform/x86/intel/pmt/telemetry.c
> @@ -219,7 +219,7 @@ int pmt_telem_read(struct telem_endpoint *ep, u32 id, u64 *data, u32 count)
>  	if (offset + NUM_BYTES_QWORD(count) > size)
>  		return -EINVAL;
>  
> -	pmt_telem_read_mmio(ep->pcidev, ep->cb, ep->header.guid, data, ep->base + offset,
> +	pmt_telem_read_mmio(ep->pcidev, ep->cb, ep->header.guid, data, ep->base, offset,
>  			    NUM_BYTES_QWORD(count));
>  
>  	return ep->present ? 0 : -EPIPE;
> diff --git a/include/linux/intel_vsec.h b/include/linux/intel_vsec.h
> index 11ee185566c3..b94beab64610 100644
> --- a/include/linux/intel_vsec.h
> +++ b/include/linux/intel_vsec.h
> @@ -74,10 +74,11 @@ enum intel_vsec_quirks {
>   * @pdev:  PCI device reference for the callback's use
>   * @guid:  ID of data to acccss
>   * @data:  buffer for the data to be copied
> + * @off:   offset into the requested buffer
>   * @count: size of buffer
>   */
>  struct pmt_callbacks {
> -	int (*read_telem)(struct pci_dev *pdev, u32 guid, u64 *data, u32 count);
> +	int (*read_telem)(struct pci_dev *pdev, u32 guid, u64 *data, loff_t off, u32 count);
>  };
>  
>  /**
>