Re: [RFC PATCH v4 1/6] vfio: Define device specific irq type capability

Zhenyu Wang
2019-07-19T06:09:01Z

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On 2019.07.18 23:56:35 +0800, Kechen Lu wrote:
> From: Tina Zhang <tina.zhang@intel.com>
>
> Cap the number of irqs with fixed indexes and use capability chains
> to chain device specific irqs.
>
> 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(-)
>
> 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 starts after
vfio_irq_info.

> };
> #define VFIO_DEVICE_GET_IRQ_INFO _IO(VFIO_TYPE, VFIO_BASE + 9)
>
> +/*
> + * 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_irq_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 = 5 /* Fixed user ABI, IRQ indexes >=5 use */
> + /* device specific cap to define content */
> };
>
> /*
> --
> 2.17.1
>

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