On 7/25/19 8:09 PM, Daniel Henrique Barboza wrote:
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 <danielhb...@gmail.com>
---
src/util/virhostdev.c | 74 +++++++++++++++++++++++++++++++++----------
1 file changed, 57 insertions(+), 17 deletions(-)
As you pointed out, I've sent a patch for the same issue. And if you
don't mind, I'd like to go with mine, because it's shorter and simpler.
Michal
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