mmap the iomem range of the PCI device fails for kernels that
enabled CONFIG_IO_STRICT_DEVMEM option:
EAL: pci_map_resource():
cannot mmap(39, 0x7f1c51800000, 0x100000, 0x0):
Invalid argument (0xffffffffffffffff)
CONFIG_IO_STRICT_DEVMEM is introduced in Linux v4.5 and not enabled
by default:
Linux commit: 90a545e restrict /dev/mem to idle io memory ranges
As a workaround igb_uio can stop reserving PCI memory resources, from
kernel point of view iomem region looks like idle and mmap works
again. This matches uio_pci_generic usage.
With this update device iomem range is not protected against any
other kernel drivers or userspace access. But this shouldn't
be a problem for dpdk usage module since purpose of the igb_uio
module is to provide userspace access.
Fixes: af75078fece3 ("first public release")
Signed-off-by: Ferruh Yigit <ferruh.yigit at intel.com>
---
v4:
* release notes, resolved issues section updated for this fix
---
doc/guides/rel_notes/release_16_07.rst | 14 ++++++++++++++
lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 13 -------------
2 files changed, 14 insertions(+), 13 deletions(-)
diff --git a/doc/guides/rel_notes/release_16_07.rst
b/doc/guides/rel_notes/release_16_07.rst
index 569f562..1ddcdab 100644
--- a/doc/guides/rel_notes/release_16_07.rst
+++ b/doc/guides/rel_notes/release_16_07.rst
@@ -231,6 +231,20 @@ Examples
Other
~~~~~
+* **igb_uio: Fixed possible mmap failure for Linux >= v4.5.**
+
+ mmaping the iomem range of the PCI device fails for kernels that
+ enabled CONFIG_IO_STRICT_DEVMEM option:
+
+ EAL: pci_map_resource():
+ cannot mmap(39, 0x7f1c51800000, 0x100000, 0x0):
+ Invalid argument (0xffffffffffffffff)
+
+ CONFIG_IO_STRICT_DEVMEM is introduced in Linux v4.5
+
+ Updated igb_uio to stop reserving PCI memory resources, from
+ kernel point of view iomem region looks like idle and mmap worked
+ again. This matches uio_pci_generic usage.
Known Issues
------------
diff --git a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
index 45a5720..df41e45 100644
--- a/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
+++ b/lib/librte_eal/linuxapp/igb_uio/igb_uio.c
@@ -342,16 +342,6 @@ igbuio_pci_probe(struct pci_dev *dev, const struct
pci_device_id *id)
goto fail_free;
}
- /*
- * reserve device's PCI memory regions for use by this
- * module
- */
- err = pci_request_regions(dev, "igb_uio");
- if (err != 0) {
- dev_err(&dev->dev, "Cannot request regions\n");
- goto fail_disable;
- }
-
/* enable bus mastering on the device */
pci_set_master(dev);
@@ -441,8 +431,6 @@ fail_release_iomem:
igbuio_pci_release_iomem(&udev->info);
if (udev->mode == RTE_INTR_MODE_MSIX)
pci_disable_msix(udev->pdev);
- pci_release_regions(dev);
-fail_disable:
pci_disable_device(dev);
fail_free:
kfree(udev);
@@ -460,7 +448,6 @@ igbuio_pci_remove(struct pci_dev *dev)
igbuio_pci_release_iomem(&udev->info);
if (udev->mode == RTE_INTR_MODE_MSIX)
pci_disable_msix(dev);
- pci_release_regions(dev);
pci_disable_device(dev);
pci_set_drvdata(dev, NULL);
kfree(udev);
--
2.7.4
