> -----Original Message-----
> From: Alex Williamson [mailto:alex.william...@redhat.com]
> Sent: Thursday, June 27, 2019 12:08 PM
> To: Zhang, Tina <tina.zh...@intel.com>
> Cc: intel-gvt-...@lists.freedesktop.org; k...@vger.kernel.org; linux-
> ker...@vger.kernel.org; kra...@redhat.com; zhen...@linux.intel.com; Lv,
> Zhiyuan <zhiyuan...@intel.com>; Wang, Zhi A <zhi.a.w...@intel.com>; Tian,
> Kevin <kevin.t...@intel.com>; Yuan, Hang <hang.y...@intel.com>
> Subject: Re: [RFC PATCH v3 1/4] vfio: Define device specific irq type
> capability
>
> On Thu, 27 Jun 2019 11:37:59 +0800
> Tina Zhang <tina.zh...@intel.com> wrote:
>
> > Cap the number of irqs with fixed indexes and use capability chains to
> > chain device specific irqs.
> >
> > Signed-off-by: Tina Zhang <tina.zh...@intel.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 02bb7ad6e986..600784acc4ac 100644
> > --- a/include/uapi/linux/vfio.h
> > +++ b/include/uapi/linux/vfio.h
> > @@ -444,11 +444,27 @@ 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 cap_offset; /* Offset within info struct of first cap */
> > __u32 count; /* Number of IRQs within this index */
> > };
>
>
> This cannot be inserted into the middle of the structure, it breaks
> compatibility with all existing userspace binaries. I must be added to the
> end
> of the structure.
Indeed. Thanks.
BR,
Tina
>
> > #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)
> > *
> > @@ -550,7 +566,8 @@ 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 */
> > };
> >
> > /*
