Re: [PATCH v2 28/30] vfio-pci/zdev: add DTSM to clp group capability

[Pierre Morel <pmorel@linux.ibm.com>]

On 1/14/22 21:31, Matthew Rosato wrote:
> The DTSM, or designation type supported mask, indicates what IOAT formats
> are available to the guest.  For an interpreted device, userspace will not
> know what format(s) the IOAT assist supports, so pass it via the
> capability chain.  Since the value belongs to the Query PCI Function Group
> clp, let's extend the existing capability with a new version.
> 
> Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>



> ---
>   drivers/vfio/pci/vfio_pci_zdev.c | 9 ++++++---
>   include/uapi/linux/vfio_zdev.h   | 3 +++
>   2 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/vfio/pci/vfio_pci_zdev.c b/drivers/vfio/pci/vfio_pci_zdev.c
> index 2b169d688937..aa2ef9067c7d 100644
> --- a/drivers/vfio/pci/vfio_pci_zdev.c
> +++ b/drivers/vfio/pci/vfio_pci_zdev.c
> @@ -45,19 +45,22 @@ static int zpci_group_cap(struct zpci_dev *zdev, struct vfio_info_cap *caps)
>   {
>   	struct vfio_device_info_cap_zpci_group cap = {
>   		.header.id = VFIO_DEVICE_INFO_CAP_ZPCI_GROUP,
> -		.header.version = 1,
> +		.header.version = 2,
>   		.dasm = zdev->dma_mask,
>   		.msi_addr = zdev->msi_addr,
>   		.flags = VFIO_DEVICE_INFO_ZPCI_FLAG_REFRESH,
>   		.mui = zdev->fmb_update,
>   		.noi = zdev->max_msi,
>   		.maxstbl = ZPCI_MAX_WRITE_SIZE,
> -		.version = zdev->version
> +		.version = zdev->version,
> +		.dtsm = 0
>   	};
>   
>   	/* Some values are different for interpreted devices */
> -	if (zdev->kzdev && zdev->kzdev->interp)
> +	if (zdev->kzdev && zdev->kzdev->interp) {
>   		cap.maxstbl = zdev->maxstbl;
> +		cap.dtsm = kvm_s390_pci_get_dtsm(zdev);
> +	}
>   
>   	return vfio_info_add_capability(caps, &cap.header, sizeof(cap));
>   }
> diff --git a/include/uapi/linux/vfio_zdev.h b/include/uapi/linux/vfio_zdev.h
> index 1a5229b7bb18..b4c2ba8e71f0 100644
> --- a/include/uapi/linux/vfio_zdev.h
> +++ b/include/uapi/linux/vfio_zdev.h
> @@ -47,6 +47,9 @@ struct vfio_device_info_cap_zpci_group {
>   	__u16 noi;		/* Maximum number of MSIs */
>   	__u16 maxstbl;		/* Maximum Store Block Length */
>   	__u8 version;		/* Supported PCI Version */
> +	/* End of version 1 */
> +	__u8 dtsm;		/* Supported IOAT Designations */
> +	/* End of version 2 */
>   };
>   
>   /**
> 

-- 
Pierre Morel
IBM Lab Boeblingen