Messages in this thread | | | Date | Sat, 17 Apr 2010 21:34:32 +0300 | From | Avi Kivity <> | Subject | Re: [PATCH V2] drivers/uio/uio.c: DMA mapping, interrupt extensions, etc. |
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On 04/15/2010 11:55 PM, Tom Lyon wrote: > This is the second of 2 related, but independent, patches. This is for > uio.c, the previous is for uio_pci_generic.c. > > The 2 patches were previously one large patch. Changes for this version: > - uio_pci_generic.c just gets extensions so that a single fd can be used > by non-privileged processes for interrupt control and mmaps > - All of the DMA and IOMMU related stuff move to uio.c; no longer a need > to pass ioctls to individual uio drivers. It turns out that the code > is not PCI specific anyways. > - A new ioctl to pin DMA buffers to certain IO virtual addresses for KVM. > - New eventfd based interrupt notifications, including support for PCI > specific MSI and MSI-X interrupts. > - PCI specific code to reset PCI functions before and after use > > > @@ -122,4 +126,23 @@ > #define UIO_PORT_GPIO 2 > #define UIO_PORT_OTHER 3 > > +#endif /* __KERNEL__ */ > + > +// Kernel& User level defines for ioctls > + > +struct uio_dma_map { > + unsigned long vaddr; > + unsigned long long dmaaddr; >
Use __u64 for both, otherwise you need to rewrite the structures in the kernel in case 32-bit userspace calls a 64-bit kernel.
> + int size; >
What units? Size is probably too small. Suggest unsigned type to avoid an extra check in the kernel.
> + int rdwr; >
What values can this hold?
> +}; > + > +#define UIO_DMA_MAP_ANYWHERE _IOWR(';', 100, struct uio_dma_map) >
What does this do? Ignore vaddr?
> +#define UIO_DMA_MAP_IOVA _IOWR(';', 101, struct uio_dma_map) > +#define UIO_DMA_UNMAP _IOW(';', 102, struct uio_dma_map) > +#define UIO_DMA_MASK _IOW(';', 103, unsigned long long) > +#define UIO_EVENTFD_IRQ _IOW(';', 104, int) > +#define UIO_EVENTFD_MSI _IOW(';', 105, int) > +#define UIO_EVENTFDS_MSIX _IOW(';', 106, int) >
These three need some documentation.
-- Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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