On Mon, 2011-09-26 at 15:03 -0500, Stuart Yoder wrote:
> >
> > The other obvious possibility is a pure ioctl interface. To match what
> > this proposal is trying to describe, plus the runtime interfaces, we'd
> > need something like:
> >
> > /* :0 - PCI devices, :1 - Devices path device, 63:2 - reserved */
> > #define VFIO_DEVICE_GET_FLAGS _IOR(, , u64)
> >
> >
> > /* Return number of mmio/iop/config regions.
> > * For PCI this is always 8 (BAR0-5 + ROM + Config) */
> > #define VFIO_DEVICE_GET_NUM_REGIONS _IOR(, , int)
> >
> > /* Return length for region index (may be zero) */
> > #define VFIO_DEVICE_GET_REGION_LEN _IOWR(, , u64)
> >
> > /* Return flags for region index
> > * :0 - mmap'able, :1 - read-only, 63:2 - reserved */
> > #define VFIO_DEVICE_GET_REGION_FLAGS _IOR(, , u64)
> >
> > /* Return file offset for region index */
> > #define VFIO_DEVICE_GET_REGION_OFFSET _IOWR(, , u64)
> >
> > /* Return physical address for region index - not implemented for PCI */
> > #define VFIO_DEVICE_GET_REGION_PHYS_ADDR _IOWR(, , u64)
> >
> >
> >
> > /* Return number of IRQs (Not including MSI/MSI-X for PCI) */
> > #define VFIO_DEVICE_GET_NUM_IRQ _IOR(, , int)
> >
> > /* Set IRQ eventfd for IRQ index, arg[0] = index, arg[1] = fd */
> > #define VFIO_DEVICE_SET_IRQ_EVENTFD _IOW(, , int)
> >
> > /* Unmask IRQ index */
> > #define VFIO_DEVICE_UNMASK_IRQ _IOW(, , int)
> >
> > /* Set unmask eventfd for index, arg[0] = index, arg[1] = fd */
> > #define VFIO_DEVICE_SET_UNMASK_IRQ_EVENTFD _IOW(, , int)
> >
> >
> > /* Return the device tree path for type/index into the user
> > * allocated buffer */
> > struct dtpath {
> > u32 type; (0 = region, 1 = IRQ)
> > u32 index;
> > u32 buf_len;
> > char *buf;
> > };
> > #define VFIO_DEVICE_GET_DTPATH _IOWR(, , struct dtpath)
> >
> > /* Return the device tree index for type/index */
> > struct dtindex {
> > u32 type; (0 = region, 1 = IRQ)
> > u32 index;
> > u32 prop_type;
> > u32 prop_index;
> > };
> > #define VFIO_DEVICE_GET_DTINDEX _IOWR(, , struct dtindex)
> >
> >
> > /* Reset the device */
> > #define VFIO_DEVICE_RESET _IO(, ,)
> >
> >
> > /* PCI MSI setup, arg[0] = #, arg[1-n] = eventfds */
> > #define VFIO_DEVICE_PCI_SET_MSI_EVENTFDS _IOW(, , int)
> > #define VFIO_DEVICE_PCI_SET_MSIX_EVENTFDS _IOW(, , int)
> >
> > Hope that covers it. Something I prefer about this interface is that
> > everything can easily be generated on the fly, whereas reading out a
> > table from the device means we really need to have that table somewhere
> > in kernel memory to easily support reading random offsets. Thoughts?
>
> I think this could work, but I'm not sure it makes the problem David
> had any better-- you substitute the complexity of parsing the
> variable length regions with invoking a set of APIs.
I read it as mostly the complexity problem, which I think this makes
fairly trivial. It also eliminates a lot of complexity on the kernel
side of supporting the table driven interface. Thanks,
Alex
if (!(GET_FLAGS & PCI))
return error;
if (GET_NUM_REGIONS < 8)
return error;
GET_REGION_LEN(7)
GET_REGION_OFFSET(7) // setup config access
for (i = 0; i < 6; i++) {
if (GET_REGION_LEN(i)) {
GET_REGION_OFFSET(i)
setup mmap/rw
}
}
if (GET_REGION_LEN(6)) {
GET_REGION_OFFSET(6)
setup ROM access
}
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