From: Avi Kivity <avi@redhat.com>
To: Tom Lyon <pugs@cisco.com>
Cc: mst@redhat.com, hjk@linutronix.de, gregkh@suse.de,
chrisw@sous-sol.org, joro@8bytes.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] drivers/uio/uio.c: DMA mapping, interrupt extensions, etc.
Date: Sat, 17 Apr 2010 21:34:32 +0300 [thread overview]
Message-ID: <4BC9FF38.7040009@redhat.com> (raw)
In-Reply-To: <4bc77d41.njZFTBp9Nkn93l72%pugs@cisco.com>
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.
prev parent reply other threads:[~2010-04-17 18:35 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-15 20:55 [PATCH V2] drivers/uio/uio.c: DMA mapping, interrupt extensions, etc Tom Lyon
2010-04-17 10:43 ` Joerg Roedel
2010-04-17 17:04 ` Tom Lyon
2010-04-17 18:34 ` Avi Kivity [this message]
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