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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.c234
1 files changed, 71 insertions, 163 deletions
diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
index f72323ef618..e9d78eb91ed 100644
--- a/drivers/vfio/pci/vfio_pci_rdwr.c
+++ b/drivers/vfio/pci/vfio_pci_rdwr.c
@@ -20,250 +20,158 @@
#include "vfio_pci_private.h"
-/* I/O Port BAR access */
-ssize_t vfio_pci_io_readwrite(struct vfio_pci_device *vdev, char __user *buf,
- size_t count, loff_t *ppos, bool iswrite)
+/*
+ * 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)
{
- struct pci_dev *pdev = vdev->pdev;
- loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
- int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
- void __iomem *io;
- size_t done = 0;
-
- if (!pci_resource_start(pdev, bar))
- return -EINVAL;
-
- if (pos + count > pci_resource_len(pdev, bar))
- return -EINVAL;
-
- if (!vdev->barmap[bar]) {
- int ret;
-
- ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
- if (ret)
- return ret;
-
- vdev->barmap[bar] = pci_iomap(pdev, bar, 0);
-
- if (!vdev->barmap[bar]) {
- pci_release_selected_regions(pdev, 1 << bar);
- return -EINVAL;
- }
- }
-
- io = vdev->barmap[bar];
+ ssize_t done = 0;
while (count) {
- int filled;
+ 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 (count >= 3 && !(pos % 4)) {
+ if (fillable >= 4 && !(off % 4)) {
__le32 val;
if (iswrite) {
if (copy_from_user(&val, buf, 4))
return -EFAULT;
- iowrite32(le32_to_cpu(val), io + pos);
+ iowrite32(le32_to_cpu(val), io + off);
} else {
- val = cpu_to_le32(ioread32(io + pos));
+ val = cpu_to_le32(ioread32(io + off));
if (copy_to_user(buf, &val, 4))
return -EFAULT;
}
filled = 4;
-
- } else if ((pos % 2) == 0 && count >= 2) {
+ } 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 + pos);
+ iowrite16(le16_to_cpu(val), io + off);
} else {
- val = cpu_to_le16(ioread16(io + pos));
+ val = cpu_to_le16(ioread16(io + off));
if (copy_to_user(buf, &val, 2))
return -EFAULT;
}
filled = 2;
- } else {
+ } else if (fillable) {
u8 val;
if (iswrite) {
if (copy_from_user(&val, buf, 1))
return -EFAULT;
- iowrite8(val, io + pos);
+ iowrite8(val, io + off);
} else {
- val = ioread8(io + pos);
+ 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;
- pos += filled;
}
- *ppos += done;
-
return done;
}
-/*
- * MMIO BAR access
- * We handle two excluded ranges here as well, if the user tries to read
- * the ROM beyond what PCI tells us is available or the MSI-X table region,
- * we return 0xFF and writes are dropped.
- */
-ssize_t vfio_pci_mem_readwrite(struct vfio_pci_device *vdev, char __user *buf,
- size_t count, loff_t *ppos, bool iswrite)
+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);
- void __iomem *io;
+ size_t x_start = 0, x_end = 0;
resource_size_t end;
- size_t done = 0;
- size_t x_start = 0, x_end = 0; /* excluded range */
+ void __iomem *io;
+ ssize_t done;
if (!pci_resource_start(pdev, bar))
return -EINVAL;
end = pci_resource_len(pdev, bar);
- if (pos > end)
+ if (pos >= end)
return -EINVAL;
- if (pos == end)
- return 0;
-
- if (pos + count > end)
- count = end - pos;
+ 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;
+ } else if (!vdev->barmap[bar]) {
+ int ret;
- vdev->barmap[bar] = pci_iomap(pdev, bar, 0);
+ ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
+ if (ret)
+ return ret;
- if (!vdev->barmap[bar]) {
- pci_release_selected_regions(pdev, 1 << bar);
- return -EINVAL;
- }
+ 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;
- }
+ if (bar == vdev->msix_bar) {
+ x_start = vdev->msix_offset;
+ x_end = vdev->msix_offset + vdev->msix_size;
}
- if (!io)
- return -EINVAL;
-
- while (count) {
- size_t fillable, filled;
-
- if (pos < x_start)
- fillable = x_start - pos;
- else if (pos >= x_end)
- fillable = end - pos;
- else
- fillable = 0;
-
- if (fillable >= 4 && !(pos % 4) && (count >= 4)) {
- __le32 val;
-
- if (iswrite) {
- if (copy_from_user(&val, buf, 4))
- goto out;
-
- iowrite32(le32_to_cpu(val), io + pos);
- } else {
- val = cpu_to_le32(ioread32(io + pos));
-
- if (copy_to_user(buf, &val, 4))
- goto out;
- }
-
- filled = 4;
- } else if (fillable >= 2 && !(pos % 2) && (count >= 2)) {
- __le16 val;
-
- if (iswrite) {
- if (copy_from_user(&val, buf, 2))
- goto out;
-
- iowrite16(le16_to_cpu(val), io + pos);
- } else {
- val = cpu_to_le16(ioread16(io + pos));
-
- if (copy_to_user(buf, &val, 2))
- goto out;
- }
-
- filled = 2;
- } else if (fillable) {
- u8 val;
-
- if (iswrite) {
- if (copy_from_user(&val, buf, 1))
- goto out;
-
- iowrite8(val, io + pos);
- } else {
- val = ioread8(io + pos);
-
- if (copy_to_user(buf, &val, 1))
- goto out;
- }
-
- filled = 1;
- } else {
- /* Drop writes, fill reads with FF */
- filled = min((size_t)(x_end - pos), count);
- if (!iswrite) {
- char val = 0xFF;
- size_t i;
+ done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite);
- for (i = 0; i < filled; i++) {
- if (put_user(val, buf + i))
- goto out;
- }
- }
+ if (done >= 0)
+ *ppos += done;
- }
-
- count -= filled;
- done += filled;
- buf += filled;
- pos += filled;
- }
-
- *ppos += done;
-
-out:
if (bar == PCI_ROM_RESOURCE)
pci_unmap_rom(pdev, io);
- return count ? -EFAULT : done;
+ return done;
}
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