Coverity complains about "USE_AFTER_FREE" due to how virPCIDeviceSetStubDriver
"could" return either -1, 0, or 1 from the VIR_STRDUP() and then possibly makes
a call to virPCIDeviceDetach().
The only way this could happen is if NULL were passed as the "driver" name
and virStrdup() returned 0. Since the calling functions check < 0 on the
initial function call, the 0 possibility causes Coverity to complain.
To fix this - enforce that the second parameter is not NULL using
ATTRIBUTE_NONNULL(2) for the function prototype, then in virPCIDeviceDetach
add an sa_assert(dev->stubDriver). This will result in Coverity not complaining
any more.
Like commit 94a26c7e from Eric Blake, the old fuzzy code should
be replaced by the new array management macros now.
And the type of scsi->count should be changed into "size_t", and
thus virSCSIDeviceListCount should return size_t instead, similar
for vir{PCI,USB}DeviceListCount.
Any device which belongs to an "IOMMU group" (used by vfio) will
have links to all devices of its group listed in
/sys/bus/pci/$device/iommu_group/devices;
/sys/bus/pci/$device/iommu_group is actually a link to
/sys/kernel/iommu_groups/$n, where $n is the group number (there
will be a corresponding device node at /dev/vfio/$n once the
devices are bound to the vfio-pci driver)
The following functions are added:
virPCIDeviceGetIOMMUGroupList
Gets a virPCIDeviceList with one virPCIDeviceList for each device
in the same IOMMU group as the provided virPCIDevice (a copy of the
original device object is included in the list.
virPCIDeviceAddressIOMMUGroupIterate
Calls the function @actor once for each device in the group that
contains the given virPCIDeviceAddress.
virPCIDeviceAddressGetIOMMUGroupAddresses
Fills in a virPCIDeviceAddressPtr * with an array of
virPCIDeviceAddress, one for each device in the iommu group of the
provided virPCIDeviceAddress (including a copy of the original).
virPCIDeviceAddressGetIOMMUGroupNum
Returns the group number as an int (a valid group number will always
be 0 or greater). If there is no iommu_group link in the device's
directory (usually indicating that vfio isn't loaded), -2 will be
returned. On any real error, -1 will be returned.
I realized after the fact that it's probably better in the long run to
give this function a name that matches the name of the link used in
sysfs to hold the group (iommu_group).
I'm changing it now because I'm about to add several more functions
that deal with iommu groups.
The driver arg to virPCIDeviceDetach is no longer used (the name of the stub driver is now set in the virPCIDevice object, and virPCIDeviceDetach retrieves it from there). Remove it.
* virPCIDeviceFindByIDs - find a device on a list w/o creating an object
This makes searching for an existing device on a list lighter weight.
* virPCIDeviceCopy - make a copy of an existing virPCIDevice object.
* virPCIDeviceGetDriverPathAndName - construct new strings containing
1) the name of the driver bound to this device.
2) the full path to the sysfs config for that driver.
(This code was lifted from virPCIDeviceUnbindFromStub, and replaced
there with a call to this new function).
Previously stubDriver was always set from a string literal, so it was
okay to use a const char * that wasn't freed when the virPCIDevice was
freed. This will not be the case in the near future, so it is now a
char* that is allocated in virPCIDeviceSetStubDriver() and freed
during virPCIDeviceFree().
virPCIDeviceReattach and virPCIDeviceUnbindFromStub (called by
virPCIDeviceReattach) had previously required the name of the stub
driver as input. This is unnecessary, because the name of the driver
the device is currently bound to can be found by looking at the link:
/sys/bus/pci/dddd:bb:ss.ff/driver
Instead of requiring that the name of the expected stub driver name
and only unbinding if that one name is matched, we no longer take a
driver name in the arglist for either of these
functions. virPCIDeviceUnbindFromStub just compares the name of the
currently bound driver to a list of "well known" stubs (right now
contains "pci-stub" and "vfio-pci" for qemu, and "pciback" for xen),
and only performs the unbind if it's one of those devices.
This allows virsh nodedevice-reattach to work properly across a
libvirtd restart, and fixes a couple of cases where we were
erroneously still hard-coding "pci-stub" as the drive name.
For some unknown reason, virPCIDeviceReattach had been calling
modprobe on the stub driver prior to unbinding the device. This was
problematic because we no longer know the name of the stub driver in
that function. However, it is pointless to probe for the stub driver
at that time anyway - because the device is bound to the stub driver,
we are guaranteed that it is already loaded, and so that call to
modprobe has been removed.
This can be set when the virPCIDevice is created and placed on a list,
then used later when traversing the list to determine which stub
driver to bind/unbind for managed devices.
The existing Detach and Attach functions' signatures haven't been
changed (they still accept a stub driver name in the arg list), but if
the arg list has NULL for stub driver and one is available in the
device's object, that will be used. (we may later deprecate and remove
the arg from those functions).
Though they are the same thing, mixed use of them is uncomfortable.
"unsigned" is used a lot in old codes, this just tries to change the
ones in utils.
To allow modifications to the lists to be synchronized, convert
virPCIDeviceList and virUSBDeviceList into virObjectLockable
classes. The locking, however, will not be self-contained. The
users of these classes will have to call virObjectLock/Unlock
in the critical regions.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Pass stub driver name directly to pciDettachDevice and pciReAttachDevice to fit
for different libvirt drivers. For example, qemu driver prefers pci-stub, but
Xen prefers pciback.
Signed-off-by: Chunyan Liu <cyliu@suse.com>
