Hi, Damjan,
The issue existing in the code is container fd is initialized as “-1”, and
there is no code to update it before trying to read iommu_group in pci.c, and
container_fd is the condition required. See below code.
if (lvm->container_fd != -1)
{
u8 *tmpstr;
vec_reset_length (f);
f = format (f, "%v/iommu_group%c", dev_dir_name, 0);
tmpstr = clib_sysfs_link_to_name ((char *) f);
if (tmpstr)
{
di->iommu_group = atoi ((char *) tmpstr);
vec_free (tmpstr);
}
From: Damjan Marion [mailto:dmar...@me.com]
Sent: Sunday, December 30, 2018 7:10 PM
To: Yu, Ping <ping...@intel.com>
Cc: vpp-dev@lists.fd.io
Subject: Re: [vpp-dev] found some issue in pci vfio
Fact that you can open vfio container doesn't actually mean that you can use
vfio-pci module on specific PCI device.
vfio-pci module can be used in 2 cases:
- when /sys/bus/pci/devices/<PCI ADDRESS>/iommu_group exists
- when /sys/module/vfio/parameters/enable_unsafe_noiommu_mode is set to Y
(introduced in kernel 4.4)
That code needs to be fixed, but I don't think your fix is the right one....
On 29 Dec 2018, at 04:46, Yu, Ping
<ping...@intel.com<mailto:ping...@intel.com>> wrote:
I submitted a patch to fix it.
https://gerrit.fd.io/r/16640
Ping
From: Yu, Ping
Sent: Saturday, December 29, 2018 10:43 AM
To: vpp-dev@lists.fd.io<mailto:vpp-dev@lists.fd.io>
Cc: Yu, Ping <ping...@intel.com<mailto:ping...@intel.com>>
Subject: found some issue in pci vfio
Hello, all
Recently I met some issue in vfio, and below is some root cause:
Before running vpp, I will use “dpdk-devbind.py” to bind the NIC to vfio-pci,
and then use “uio-driver auto” configure, and it once worked well, but it has
problem recently, so I took a look at this to resolve the problem.
I found that vpp has some problem to “auto” detect the uio-driver to be vfio,
and the bug info is below:
1) vlib_pci_bind_to_uio is dependent vlib_pci_get_device_info to tell
iommu_group
2) vlib_pci_get_device_info will check whether lvm->container_fd == -1
In my case, lvm->container_fd is initialized to be “-1”, and there is no chance
to modify it, so in the eye of vlib_pci_bind_to_uio, iommu_group is -1, then it
will try to enable noiommu mode. If some kernel enabled NOIOMMU, then vfio can
continue work with noiommu mode, but if not, then this device will be rejected
due to “no VFIO” support. (pci.c # 411. )
The solution is to drop “auto” mode, and explicitly configure “vfio-pci” in the
configuration, but I hope the default “auto” mode can be smarter.
Ping
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