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path: root/drivers/vfio/pci/vfio_pci_rdwr.c
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Diffstat (limited to 'drivers/vfio/pci/vfio_pci_rdwr.c')
-rw-r--r--drivers/vfio/pci/vfio_pci_rdwr.c502
1 files changed, 502 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
new file mode 100644
index 000000000..e352a033b
--- /dev/null
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -0,0 +1,502 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * VFIO PCI I/O Port & MMIO access
+ *
+ * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
+ * Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * 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/vfio.h>
+#include <linux/vgaarb.h>
+
+#include "vfio_pci_priv.h"
+
+#ifdef __LITTLE_ENDIAN
+#define vfio_ioread64 ioread64
+#define vfio_iowrite64 iowrite64
+#define vfio_ioread32 ioread32
+#define vfio_iowrite32 iowrite32
+#define vfio_ioread16 ioread16
+#define vfio_iowrite16 iowrite16
+#else
+#define vfio_ioread64 ioread64be
+#define vfio_iowrite64 iowrite64be
+#define vfio_ioread32 ioread32be
+#define vfio_iowrite32 iowrite32be
+#define vfio_ioread16 ioread16be
+#define vfio_iowrite16 iowrite16be
+#endif
+#define vfio_ioread8 ioread8
+#define vfio_iowrite8 iowrite8
+
+#define VFIO_IOWRITE(size) \
+static int vfio_pci_iowrite##size(struct vfio_pci_core_device *vdev, \
+ bool test_mem, u##size val, void __iomem *io) \
+{ \
+ if (test_mem) { \
+ down_read(&vdev->memory_lock); \
+ if (!__vfio_pci_memory_enabled(vdev)) { \
+ up_read(&vdev->memory_lock); \
+ return -EIO; \
+ } \
+ } \
+ \
+ vfio_iowrite##size(val, io); \
+ \
+ if (test_mem) \
+ up_read(&vdev->memory_lock); \
+ \
+ return 0; \
+}
+
+VFIO_IOWRITE(8)
+VFIO_IOWRITE(16)
+VFIO_IOWRITE(32)
+#ifdef iowrite64
+VFIO_IOWRITE(64)
+#endif
+
+#define VFIO_IOREAD(size) \
+static int vfio_pci_ioread##size(struct vfio_pci_core_device *vdev, \
+ bool test_mem, u##size *val, void __iomem *io) \
+{ \
+ if (test_mem) { \
+ down_read(&vdev->memory_lock); \
+ if (!__vfio_pci_memory_enabled(vdev)) { \
+ up_read(&vdev->memory_lock); \
+ return -EIO; \
+ } \
+ } \
+ \
+ *val = vfio_ioread##size(io); \
+ \
+ if (test_mem) \
+ up_read(&vdev->memory_lock); \
+ \
+ return 0; \
+}
+
+VFIO_IOREAD(8)
+VFIO_IOREAD(16)
+VFIO_IOREAD(32)
+
+/*
+ * 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(struct vfio_pci_core_device *vdev, bool test_mem,
+ 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;
+ int ret;
+
+ 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)) {
+ u32 val;
+
+ if (iswrite) {
+ if (copy_from_user(&val, buf, 4))
+ return -EFAULT;
+
+ ret = vfio_pci_iowrite32(vdev, test_mem,
+ val, io + off);
+ if (ret)
+ return ret;
+ } else {
+ ret = vfio_pci_ioread32(vdev, test_mem,
+ &val, io + off);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(buf, &val, 4))
+ return -EFAULT;
+ }
+
+ filled = 4;
+ } else if (fillable >= 2 && !(off % 2)) {
+ u16 val;
+
+ if (iswrite) {
+ if (copy_from_user(&val, buf, 2))
+ return -EFAULT;
+
+ ret = vfio_pci_iowrite16(vdev, test_mem,
+ val, io + off);
+ if (ret)
+ return ret;
+ } else {
+ ret = vfio_pci_ioread16(vdev, test_mem,
+ &val, io + off);
+ if (ret)
+ return ret;
+
+ 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;
+
+ ret = vfio_pci_iowrite8(vdev, test_mem,
+ val, io + off);
+ if (ret)
+ return ret;
+ } else {
+ ret = vfio_pci_ioread8(vdev, test_mem,
+ &val, io + off);
+ if (ret)
+ return ret;
+
+ 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;
+}
+
+static int vfio_pci_setup_barmap(struct vfio_pci_core_device *vdev, int bar)
+{
+ struct pci_dev *pdev = vdev->pdev;
+ int ret;
+ void __iomem *io;
+
+ if (vdev->barmap[bar])
+ return 0;
+
+ 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;
+
+ return 0;
+}
+
+ssize_t vfio_pci_bar_rw(struct vfio_pci_core_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;
+ struct resource *res = &vdev->pdev->resource[bar];
+ ssize_t done;
+
+ if (pci_resource_start(pdev, bar))
+ end = pci_resource_len(pdev, bar);
+ else if (bar == PCI_ROM_RESOURCE &&
+ pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
+ end = 0x20000;
+ else
+ return -EINVAL;
+
+ 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) {
+ done = -ENOMEM;
+ goto out;
+ }
+ x_end = end;
+ } else {
+ int ret = vfio_pci_setup_barmap(vdev, bar);
+ if (ret) {
+ done = ret;
+ goto out;
+ }
+
+ 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(vdev, res->flags & IORESOURCE_MEM, io, buf, pos,
+ count, x_start, x_end, iswrite);
+
+ if (done >= 0)
+ *ppos += done;
+
+ if (bar == PCI_ROM_RESOURCE)
+ pci_unmap_rom(pdev, io);
+out:
+ return done;
+}
+
+#ifdef CONFIG_VFIO_PCI_VGA
+ssize_t vfio_pci_vga_rw(struct vfio_pci_core_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;
+
+ if (pos > 0xbfffful)
+ return -EINVAL;
+
+ switch ((u32)pos) {
+ case 0xa0000 ... 0xbffff:
+ count = min(count, (size_t)(0xc0000 - pos));
+ iomem = ioremap(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;
+ }
+
+ /*
+ * VGA MMIO is a legacy, non-BAR resource that hopefully allows
+ * probing, so we don't currently worry about access in relation
+ * to the memory enable bit in the command register.
+ */
+ done = do_io_rw(vdev, false, 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;
+}
+#endif
+
+static void vfio_pci_ioeventfd_do_write(struct vfio_pci_ioeventfd *ioeventfd,
+ bool test_mem)
+{
+ switch (ioeventfd->count) {
+ case 1:
+ vfio_pci_iowrite8(ioeventfd->vdev, test_mem,
+ ioeventfd->data, ioeventfd->addr);
+ break;
+ case 2:
+ vfio_pci_iowrite16(ioeventfd->vdev, test_mem,
+ ioeventfd->data, ioeventfd->addr);
+ break;
+ case 4:
+ vfio_pci_iowrite32(ioeventfd->vdev, test_mem,
+ ioeventfd->data, ioeventfd->addr);
+ break;
+#ifdef iowrite64
+ case 8:
+ vfio_pci_iowrite64(ioeventfd->vdev, test_mem,
+ ioeventfd->data, ioeventfd->addr);
+ break;
+#endif
+ }
+}
+
+static int vfio_pci_ioeventfd_handler(void *opaque, void *unused)
+{
+ struct vfio_pci_ioeventfd *ioeventfd = opaque;
+ struct vfio_pci_core_device *vdev = ioeventfd->vdev;
+
+ if (ioeventfd->test_mem) {
+ if (!down_read_trylock(&vdev->memory_lock))
+ return 1; /* Lock contended, use thread */
+ if (!__vfio_pci_memory_enabled(vdev)) {
+ up_read(&vdev->memory_lock);
+ return 0;
+ }
+ }
+
+ vfio_pci_ioeventfd_do_write(ioeventfd, false);
+
+ if (ioeventfd->test_mem)
+ up_read(&vdev->memory_lock);
+
+ return 0;
+}
+
+static void vfio_pci_ioeventfd_thread(void *opaque, void *unused)
+{
+ struct vfio_pci_ioeventfd *ioeventfd = opaque;
+
+ vfio_pci_ioeventfd_do_write(ioeventfd, ioeventfd->test_mem);
+}
+
+int vfio_pci_ioeventfd(struct vfio_pci_core_device *vdev, loff_t offset,
+ uint64_t data, int count, int fd)
+{
+ struct pci_dev *pdev = vdev->pdev;
+ loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
+ int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
+ struct vfio_pci_ioeventfd *ioeventfd;
+
+ /* Only support ioeventfds into BARs */
+ if (bar > VFIO_PCI_BAR5_REGION_INDEX)
+ return -EINVAL;
+
+ if (pos + count > pci_resource_len(pdev, bar))
+ return -EINVAL;
+
+ /* Disallow ioeventfds working around MSI-X table writes */
+ if (bar == vdev->msix_bar &&
+ !(pos + count <= vdev->msix_offset ||
+ pos >= vdev->msix_offset + vdev->msix_size))
+ return -EINVAL;
+
+#ifndef iowrite64
+ if (count == 8)
+ return -EINVAL;
+#endif
+
+ ret = vfio_pci_setup_barmap(vdev, bar);
+ if (ret)
+ return ret;
+
+ mutex_lock(&vdev->ioeventfds_lock);
+
+ list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
+ if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
+ ioeventfd->data == data && ioeventfd->count == count) {
+ if (fd == -1) {
+ vfio_virqfd_disable(&ioeventfd->virqfd);
+ list_del(&ioeventfd->next);
+ vdev->ioeventfds_nr--;
+ kfree(ioeventfd);
+ ret = 0;
+ } else
+ ret = -EEXIST;
+
+ goto out_unlock;
+ }
+ }
+
+ if (fd < 0) {
+ ret = -ENODEV;
+ goto out_unlock;
+ }
+
+ if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
+ ret = -ENOSPC;
+ goto out_unlock;
+ }
+
+ ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
+ if (!ioeventfd) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+
+ ioeventfd->vdev = vdev;
+ ioeventfd->addr = vdev->barmap[bar] + pos;
+ ioeventfd->data = data;
+ ioeventfd->pos = pos;
+ ioeventfd->bar = bar;
+ ioeventfd->count = count;
+ ioeventfd->test_mem = vdev->pdev->resource[bar].flags & IORESOURCE_MEM;
+
+ ret = vfio_virqfd_enable(ioeventfd, vfio_pci_ioeventfd_handler,
+ vfio_pci_ioeventfd_thread, NULL,
+ &ioeventfd->virqfd, fd);
+ if (ret) {
+ kfree(ioeventfd);
+ goto out_unlock;
+ }
+
+ list_add(&ioeventfd->next, &vdev->ioeventfds_list);
+ vdev->ioeventfds_nr++;
+
+out_unlock:
+ mutex_unlock(&vdev->ioeventfds_lock);
+
+ return ret;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 21:52:17 +0000