Re: [libvirt] [PATCH v2 3/7] util/virhostdev: enhance VFIO device is in use detection

The current virHostdevPreparePCIDevices code fails to detect an unmanaged VFIO device that is in the activePCIHostdevs, and active in the same domain name as dom_name, as a device in use. Considering a call to this function, when activePCIHostdevs has a VFIO deviceA in the list, and deviceA is active in domain 'dom_name', this is what happens: - At step 1, the code goes to the 'if (usesVFIO)' block. All devices in the same IOMMU group of deviceA are used as argument of virHostdevIsPCINodeDeviceUsed, via the IOMMUGroupIterate function; - Inside virHostdevIsPCINodeDeviceUsed, an 'usesVFIO' verification is made, following to an 'iommu_owner' jump that sets ret=0. This will happen to all devices of the IOMMU group that belongs to the same domain as dom_name, including deviceA; - Step 2 starts, thinking that all devices inside hostdevs are available, which is not the case. This error was detected when changing tests/virhostdev.c to use vfio-pci instead of pci-stub (a change that will follow this one). The side effect observed was a test failure in testVirHostdevPreparePCIHostdevs_unmanaged, result of the behavior mentioned above: Unexpected count of items in mgr->inactivePCIHostdevs: 1, expecting 0 This patch fixes virHostdevIsPCINodeDeviceUsed to consider the case of a VFIO device that is already active in the domain. First, check if the device is in the activePCIHostdev list and bail immediately if true. Otherwise, in case of VFIO, check for IOMMU group ownership of the domain. This is done by a new callback function for IOMMUGroupIterate. If the VFIO device isn't in the active list and its domain has ownership of the IOMMU, then it is unused. Signed-off-by: Daniel Henrique Barboza <danielhb413(a)gmail.com&gt; --- src/util/virhostdev.c | 74 +++++++++++++++++++++++++++++++++---------- 1 file changed, 57 insertions(+), 17 deletions(-)