linux-kernel - Re: [PATCH v2 6/7] ocxl: Add an IOCTL so userspace knows what CPU features are available

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Message-Id: <eec7dceb-0b25-8644-7f32-3700c3c4ed46@linux.ibm.com>
Date:   Mon, 7 May 2018 20:14:32 +0200
From:   Frederic Barrat <fbarrat@...ux.ibm.com>
To:     "Alastair D'Silva" <alastair@....ibm.com>,
        linuxppc-dev@...ts.ozlabs.org
Cc:     linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        mikey@...ling.org, vaibhav@...ux.vnet.ibm.com,
        aneesh.kumar@...ux.vnet.ibm.com, malat@...ian.org,
        felix@...ux.vnet.ibm.com, pombredanne@...b.com,
        sukadev@...ux.vnet.ibm.com, npiggin@...il.com,
        gregkh@...uxfoundation.org, arnd@...db.de,
        andrew.donnellan@....ibm.com, fbarrat@...ux.vnet.ibm.com,
        corbet@....net, "Alastair D'Silva" <alastair@...ilva.org>
Subject: Re: [PATCH v2 6/7] ocxl: Add an IOCTL so userspace knows what CPU
 features are available



Le 18/04/2018 à 03:08, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@...ilva.org>
> 
> In order for a userspace AFU driver to call the Power9 specific
> OCXL_IOCTL_ENABLE_P9_WAIT, it needs to verify that it can actually
> make that call.
> 
> Signed-off-by: Alastair D'Silva <alastair@...ilva.org>
> ---
>   Documentation/accelerators/ocxl.rst |  1 -
>   drivers/misc/ocxl/file.c            | 25 +++++++++++++++++++++++++
>   include/uapi/misc/ocxl.h            |  4 ++++
>   3 files changed, 29 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/accelerators/ocxl.rst b/Documentation/accelerators/ocxl.rst
> index ddcc58d01cfb..7904adcc07fd 100644
> --- a/Documentation/accelerators/ocxl.rst
> +++ b/Documentation/accelerators/ocxl.rst
> @@ -157,7 +157,6 @@ OCXL_IOCTL_GET_METADATA:
>     Obtains configuration information from the card, such at the size of
>     MMIO areas, the AFU version, and the PASID for the current context.
> 
> -


Intended?

Other than that,
Acked-by: Frederic Barrat <fbarrat@...ux.vnet.ibm.com>



>   mmap
>   ----
> 
> diff --git a/drivers/misc/ocxl/file.c b/drivers/misc/ocxl/file.c
> index eb409a469f21..33ae46ce0a8a 100644
> --- a/drivers/misc/ocxl/file.c
> +++ b/drivers/misc/ocxl/file.c
> @@ -168,12 +168,32 @@ static long afu_ioctl_enable_p9_wait(struct ocxl_context *ctx,
>   }
>   #endif
> 
> +
> +static long afu_ioctl_get_features(struct ocxl_context *ctx,
> +		struct ocxl_ioctl_features __user *uarg)
> +{
> +	struct ocxl_ioctl_features arg;
> +
> +	memset(&arg, 0, sizeof(arg));
> +
> +#ifdef CONFIG_PPC64
> +	if (cpu_has_feature(CPU_FTR_P9_TIDR))
> +		arg.flags[0] |= OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT;
> +#endif
> +
> +	if (copy_to_user(uarg, &arg, sizeof(arg)))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>   #define CMD_STR(x) (x == OCXL_IOCTL_ATTACH ? "ATTACH" :			\
>   			x == OCXL_IOCTL_IRQ_ALLOC ? "IRQ_ALLOC" :	\
>   			x == OCXL_IOCTL_IRQ_FREE ? "IRQ_FREE" :		\
>   			x == OCXL_IOCTL_IRQ_SET_FD ? "IRQ_SET_FD" :	\
>   			x == OCXL_IOCTL_GET_METADATA ? "GET_METADATA" :	\
>   			x == OCXL_IOCTL_ENABLE_P9_WAIT ? "ENABLE_P9_WAIT" :	\
> +			x == OCXL_IOCTL_GET_FEATURES ? "GET_FEATURES" :	\
>   			"UNKNOWN")
> 
>   static long afu_ioctl(struct file *file, unsigned int cmd,
> @@ -239,6 +259,11 @@ static long afu_ioctl(struct file *file, unsigned int cmd,
>   		break;
>   #endif
> 
> +	case OCXL_IOCTL_GET_FEATURES:
> +		rc = afu_ioctl_get_features(ctx,
> +				(struct ocxl_ioctl_features __user *) args);
> +		break;
> +
>   	default:
>   		rc = -EINVAL;
>   	}
> diff --git a/include/uapi/misc/ocxl.h b/include/uapi/misc/ocxl.h
> index 8d2748e69c84..bb80f294b429 100644
> --- a/include/uapi/misc/ocxl.h
> +++ b/include/uapi/misc/ocxl.h
> @@ -55,6 +55,9 @@ struct ocxl_ioctl_p9_wait {
>   	__u64 reserved3[3];
>   };
> 
> +#define OCXL_IOCTL_FEATURES_FLAGS0_P9_WAIT	0x01
> +struct ocxl_ioctl_features {
> +	__u64 flags[4];
>   };
> 
>   struct ocxl_ioctl_irq_fd {
> @@ -72,5 +75,6 @@ struct ocxl_ioctl_irq_fd {
>   #define OCXL_IOCTL_IRQ_SET_FD	_IOW(OCXL_MAGIC, 0x13, struct ocxl_ioctl_irq_fd)
>   #define OCXL_IOCTL_GET_METADATA _IOR(OCXL_MAGIC, 0x14, struct ocxl_ioctl_metadata)
>   #define OCXL_IOCTL_ENABLE_P9_WAIT	_IOR(OCXL_MAGIC, 0x15, struct ocxl_ioctl_p9_wait)
> +#define OCXL_IOCTL_GET_FEATURES _IOR(OCXL_MAGIC, 0x16, struct ocxl_ioctl_platform)
> 
>   #endif /* _UAPI_MISC_OCXL_H */
>