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Date:   Fri, 19 Jul 2019 14:05:40 +0800
From:   Zhenyu Wang <zhenyuw@linux.intel.com>
To:     Kechen Lu <kechen.lu@intel.com>
Cc:     intel-gvt-dev@lists.freedesktop.org, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Tina Zhang <tina.zhang@intel.com>,
        kraxel@redhat.com, zhenyuw@linux.intel.com, zhiyuan.lv@intel.com,
        zhi.a.wang@intel.com, kevin.tian@intel.com, hang.yuan@intel.com,
        alex.williamson@redhat.com, Eric Auger <eric.auger@redhat.com>
Subject: Re: [RFC PATCH v4 1/6] vfio: Define device specific irq type
 capability
Message-ID: <20190719060540.GC28809@zhen-hp.sh.intel.com>
Reply-To: Zhenyu Wang <zhenyuw@linux.intel.com>
References: <20190718155640.25928-1-kechen.lu@intel.com>
 <20190718155640.25928-2-kechen.lu@intel.com>
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On 2019.07.18 23:56:35 +0800, Kechen Lu wrote:
> From: Tina Zhang <tina.zhang@intel.com>
>=20
> Cap the number of irqs with fixed indexes and use capability chains
> to chain device specific irqs.
>=20
> Signed-off-by: Tina Zhang <tina.zhang@intel.com>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>  include/uapi/linux/vfio.h | 19 ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
>=20
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 8f10748dac79..be6adab4f759 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -448,11 +448,27 @@ struct vfio_irq_info {
>  #define VFIO_IRQ_INFO_MASKABLE		(1 << 1)
>  #define VFIO_IRQ_INFO_AUTOMASKED	(1 << 2)
>  #define VFIO_IRQ_INFO_NORESIZE		(1 << 3)
> +#define VFIO_IRQ_INFO_FLAG_CAPS		(1 << 4) /* Info supports caps */
>  	__u32	index;		/* IRQ index */
>  	__u32	count;		/* Number of IRQs within this index */
> +	__u32	cap_offset;	/* Offset within info struct of first cap */

This still breaks ABI as argsz would be updated with this new field, so it =
would
cause compat issue. I think my last suggestion was to assume cap list start=
s after
vfio_irq_info.

>  };
>  #define VFIO_DEVICE_GET_IRQ_INFO	_IO(VFIO_TYPE, VFIO_BASE + 9)
> =20
> +/*
> + * The irq type capability allows irqs unique to a specific device or
> + * class of devices to be exposed.
> + *
> + * The structures below define version 1 of this capability.
> + */
> +#define VFIO_IRQ_INFO_CAP_TYPE      3
> +
> +struct vfio_irq_info_cap_type {
> +	struct vfio_info_cap_header header;
> +	__u32 type;     /* global per bus driver */
> +	__u32 subtype;  /* type specific */
> +};
> +
>  /**
>   * VFIO_DEVICE_SET_IRQS - _IOW(VFIO_TYPE, VFIO_BASE + 10, struct vfio_ir=
q_set)
>   *
> @@ -554,7 +570,8 @@ enum {
>  	VFIO_PCI_MSIX_IRQ_INDEX,
>  	VFIO_PCI_ERR_IRQ_INDEX,
>  	VFIO_PCI_REQ_IRQ_INDEX,
> -	VFIO_PCI_NUM_IRQS
> +	VFIO_PCI_NUM_IRQS =3D 5	/* Fixed user ABI, IRQ indexes >=3D5 use   */
> +				/* device specific cap to define content */
>  };
> =20
>  /*
> --=20
> 2.17.1
>=20

--=20
Open Source Technology Center, Intel ltd.

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