diff options
Diffstat (limited to 'kernel/drivers/vfio/pci/vfio_pci_rdwr.c')
| -rw-r--r-- | kernel/drivers/vfio/pci/vfio_pci_rdwr.c | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/kernel/drivers/vfio/pci/vfio_pci_rdwr.c b/kernel/drivers/vfio/pci/vfio_pci_rdwr.c new file mode 100644 index 000000000..210db24d2 --- /dev/null +++ b/kernel/drivers/vfio/pci/vfio_pci_rdwr.c @@ -0,0 +1,238 @@ +/* + * VFIO PCI I/O Port & MMIO access + * + * Copyright (C) 2012 Red Hat, Inc. All rights reserved. + * Author: Alex Williamson <alex.williamson@redhat.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Derived from original vfio: + * Copyright 2010 Cisco Systems, Inc. All rights reserved. + * Author: Tom Lyon, pugs@cisco.com + */ + +#include <linux/fs.h> +#include <linux/pci.h> +#include <linux/uaccess.h> +#include <linux/io.h> +#include <linux/vgaarb.h> + +#include "vfio_pci_private.h" + +/* + * Read or write from an __iomem region (MMIO or I/O port) with an excluded + * range which is inaccessible. The excluded range drops writes and fills + * reads with -1. This is intended for handling MSI-X vector tables and + * leftover space for ROM BARs. + */ +static ssize_t do_io_rw(void __iomem *io, char __user *buf, + loff_t off, size_t count, size_t x_start, + size_t x_end, bool iswrite) +{ + ssize_t done = 0; + + while (count) { + size_t fillable, filled; + + if (off < x_start) + fillable = min(count, (size_t)(x_start - off)); + else if (off >= x_end) + fillable = count; + else + fillable = 0; + + if (fillable >= 4 && !(off % 4)) { + __le32 val; + + if (iswrite) { + if (copy_from_user(&val, buf, 4)) + return -EFAULT; + + iowrite32(le32_to_cpu(val), io + off); + } else { + val = cpu_to_le32(ioread32(io + off)); + + if (copy_to_user(buf, &val, 4)) + return -EFAULT; + } + + filled = 4; + } else if (fillable >= 2 && !(off % 2)) { + __le16 val; + + if (iswrite) { + if (copy_from_user(&val, buf, 2)) + return -EFAULT; + + iowrite16(le16_to_cpu(val), io + off); + } else { + val = cpu_to_le16(ioread16(io + off)); + + if (copy_to_user(buf, &val, 2)) + return -EFAULT; + } + + filled = 2; + } else if (fillable) { + u8 val; + + if (iswrite) { + if (copy_from_user(&val, buf, 1)) + return -EFAULT; + + iowrite8(val, io + off); + } else { + val = ioread8(io + off); + + if (copy_to_user(buf, &val, 1)) + return -EFAULT; + } + + filled = 1; + } else { + /* Fill reads with -1, drop writes */ + filled = min(count, (size_t)(x_end - off)); + if (!iswrite) { + u8 val = 0xFF; + size_t i; + + for (i = 0; i < filled; i++) + if (copy_to_user(buf + i, &val, 1)) + return -EFAULT; + } + } + + count -= filled; + done += filled; + off += filled; + buf += filled; + } + + return done; +} + +ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf, + size_t count, loff_t *ppos, bool iswrite) +{ + struct pci_dev *pdev = vdev->pdev; + loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK; + int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos); + size_t x_start = 0, x_end = 0; + resource_size_t end; + void __iomem *io; + ssize_t done; + + if (!pci_resource_start(pdev, bar)) + return -EINVAL; + + end = pci_resource_len(pdev, bar); + + if (pos >= end) + return -EINVAL; + + count = min(count, (size_t)(end - pos)); + + if (bar == PCI_ROM_RESOURCE) { + /* + * The ROM can fill less space than the BAR, so we start the + * excluded range at the end of the actual ROM. This makes + * filling large ROM BARs much faster. + */ + io = pci_map_rom(pdev, &x_start); + if (!io) + return -ENOMEM; + x_end = end; + } else if (!vdev->barmap[bar]) { + int ret; + + ret = pci_request_selected_regions(pdev, 1 << bar, "vfio"); + if (ret) + return ret; + + io = pci_iomap(pdev, bar, 0); + if (!io) { + pci_release_selected_regions(pdev, 1 << bar); + return -ENOMEM; + } + + vdev->barmap[bar] = io; + } else + io = vdev->barmap[bar]; + + if (bar == vdev->msix_bar) { + x_start = vdev->msix_offset; + x_end = vdev->msix_offset + vdev->msix_size; + } + + done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite); + + if (done >= 0) + *ppos += done; + + if (bar == PCI_ROM_RESOURCE) + pci_unmap_rom(pdev, io); + + return done; +} + +ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf, + size_t count, loff_t *ppos, bool iswrite) +{ + int ret; + loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK; + void __iomem *iomem = NULL; + unsigned int rsrc; + bool is_ioport; + ssize_t done; + + if (!vdev->has_vga) + return -EINVAL; + + switch (pos) { + case 0xa0000 ... 0xbffff: + count = min(count, (size_t)(0xc0000 - pos)); + iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1); + off = pos - 0xa0000; + rsrc = VGA_RSRC_LEGACY_MEM; + is_ioport = false; + break; + case 0x3b0 ... 0x3bb: + count = min(count, (size_t)(0x3bc - pos)); + iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1); + off = pos - 0x3b0; + rsrc = VGA_RSRC_LEGACY_IO; + is_ioport = true; + break; + case 0x3c0 ... 0x3df: + count = min(count, (size_t)(0x3e0 - pos)); + iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1); + off = pos - 0x3c0; + rsrc = VGA_RSRC_LEGACY_IO; + is_ioport = true; + break; + default: + return -EINVAL; + } + + if (!iomem) + return -ENOMEM; + + ret = vga_get_interruptible(vdev->pdev, rsrc); + if (ret) { + is_ioport ? ioport_unmap(iomem) : iounmap(iomem); + return ret; + } + + done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite); + + vga_put(vdev->pdev, rsrc); + + is_ioport ? ioport_unmap(iomem) : iounmap(iomem); + + if (done >= 0) + *ppos += done; + + return done; +} |