From ff63eb638d63b95e489f976428f1df01391e15e4 Mon Sep 17 00:00:00 2001 From: Alex Williamson Date: Mon, 22 Feb 2016 16:02:35 -0700 Subject: [PATCH] vfio: Define sparse mmap capability for regions We can't always support mmap across an entire device region, for example we deny mmaps covering the MSI-X table of PCI devices, but we don't really have a way to report it. We expect the user to implicitly know this restriction. We also can't split the region because vfio-pci defines an API with fixed region index to BAR number mapping. We therefore define a new capability which lists areas within the region that may be mmap'd. In addition to the MSI-X case, this potentially enables in-kernel emulation and extensions to devices. Signed-off-by: Alex Williamson --- include/uapi/linux/vfio.h | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index d508adf..fde7b1e 100644 --- a/include/uapi/linux/vfio.h +++ b/include/uapi/linux/vfio.h @@ -221,13 +221,37 @@ struct vfio_region_info { #define VFIO_REGION_INFO_FLAG_READ (1 << 0) /* Region supports read */ #define VFIO_REGION_INFO_FLAG_WRITE (1 << 1) /* Region supports write */ #define VFIO_REGION_INFO_FLAG_MMAP (1 << 2) /* Region supports mmap */ +#define VFIO_REGION_INFO_FLAG_CAPS (1 << 3) /* Info supports caps */ __u32 index; /* Region index */ - __u32 resv; /* Reserved for alignment */ + __u32 cap_offset; /* Offset within info struct of first cap */ __u64 size; /* Region size (bytes) */ __u64 offset; /* Region offset from start of device fd */ }; #define VFIO_DEVICE_GET_REGION_INFO _IO(VFIO_TYPE, VFIO_BASE + 8) +/* + * The sparse mmap capability allows finer granularity of specifying areas + * within a region with mmap support. When specified, the user should only + * mmap the offset ranges specified by the areas array. mmaps outside of the + * areas specified may fail (such as the range covering a PCI MSI-X table) or + * may result in improper device behavior. + * + * The structures below define version 1 of this capability. + */ +#define VFIO_REGION_INFO_CAP_SPARSE_MMAP 1 + +struct vfio_region_sparse_mmap_area { + __u64 offset; /* Offset of mmap'able area within region */ + __u64 size; /* Size of mmap'able area */ +}; + +struct vfio_region_info_cap_sparse_mmap { + struct vfio_info_cap_header header; + __u32 nr_areas; + __u32 reserved; + struct vfio_region_sparse_mmap_area areas[]; +}; + /** * VFIO_DEVICE_GET_IRQ_INFO - _IOWR(VFIO_TYPE, VFIO_BASE + 9, * struct vfio_irq_info) -- 2.7.4