diff mbox

[dpdk-dev,v2] igb_uio: fix possible mmap failure for Linux > v4.3

Message ID 1467385678-16205-1-git-send-email-ferruh.yigit@intel.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Ferruh Yigit July 1, 2016, 3:07 p.m. UTC
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 v4.4 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@intel.com>
---
 lib/librte_eal/linuxapp/igb_uio/igb_uio.c | 13 -------------
 1 file changed, 13 deletions(-)

Comments

De Lara Guarch, Pablo July 1, 2016, 3:52 p.m. UTC | #1
Hi Ferruh,

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ferruh Yigit
> Sent: Friday, July 01, 2016 4:08 PM
> To: dev@dpdk.org
> Cc: Stephen Hemminger
> Subject: [dpdk-dev] [PATCH v2] igb_uio: fix possible mmap failure for Linux >
> v4.3
> 
> 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 v4.4 and not enabled
> by default:

This was introduced in kernel 4.5 (change the title as well ;))

> 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@intel.com>
Ferruh Yigit July 1, 2016, 3:54 p.m. UTC | #2
On 7/1/2016 4:52 PM, De Lara Guarch, Pablo wrote:
> Hi Ferruh,
> 
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Ferruh Yigit
>> Sent: Friday, July 01, 2016 4:08 PM
>> To: dev@dpdk.org
>> Cc: Stephen Hemminger
>> Subject: [dpdk-dev] [PATCH v2] igb_uio: fix possible mmap failure for Linux >
>> v4.3
>>
>> 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 v4.4 and not enabled
>> by default:
> 
> This was introduced in kernel 4.5 (change the title as well ;))
"git describe" mislead me but you are right, I will update

$ git describe  90a545e
v4.4-rc5-2-g90a545e

Thanks

> 
>> 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@intel.com>
>
diff mbox

Patch

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);