[libvirt] [PATCH 00/10] VFIO fixes for PCI devices

This series is my attempt at fixing https://bugzilla.redhat.com/show_bug.cgi?id=1272300 In its current state, it's missing test cases covering the new functionality[1] and it's known not to handle properly one situation[2], but I'd like to get some feedback on my current work and now that I have something to show for it feels like a good time. I'm already working on the missing bits and they will either be included in the next revision or sent as separate series later on. The problem being solved is that, when using VFIO, IOMMU group ownership can't be shared, eg. two devices that are in the same IOMMU group can't be assigned to different guests, or to the host and a guest. If that happens, the host will probably crash. The series deals with this issue by making sure safety conditions are met before detaching devices from the host or reattaching them to the host. In praticular, when we're asked to reattach a device to the host but doing so would lead to sharing IOMMU group ownership, we delay the operation until we can guarantee this will not cause problems. As a nice side effect of the changes we check for this when starting a guest too, instead of assuming it will work and having QEMU error out immediately afterwards. Patches are organized as follows: 1-2: Minor cleanups that make implicit / confusing stuff explicit / less confusing 3: Convert a string field used as an enumeration to a proper enumeration 4: Introduce a simple helper function used later on 5-6: Rewrite the checks used when detaching devices from the host. With this patches applied, the behaviour is basically the same as before, except for the nice little extra detailed above 7-9: Implement the delay when reattaching devices to the host, thus preventing the crash and fixing the bug 10: Spit and polish Cheers. [1] Luckily, it doesn't break the existing tests either [2] If you call 'virsh nodedev-reattach' on a device that's assigned to a guest, libvirt won't stop you and you will end up crashing your system Andrea Bolognani (10): pci: Remove redundant parameter from virPCIDeviceBindToStub() pci: Remove 'reprobe' parameter from virPCIDeviceUnbind() pci: Introduce virPCIStubDriver enumeration pci: Introduce virPCIDeviceIOMMUGroupIterate() hostdev: Simplify virHostdevIsPCIDeviceUsed() hostdev: Check for safety before detaching VFIO devices hostdev: Delay reattach of VFIO devices hostdev: Clean up delayed VFIO devices hostdev: Devices have already been marked as inactive hostdev: Tidy up after changes to VFIO device handling src/libvirt_private.syms | 3 + src/libxl/libxl_driver.c | 3 +- src/qemu/qemu_driver.c | 6 +- src/util/virhostdev.c | 410 ++++++++++++++++++++++++++++++++++------------- src/util/virpci.c | 125 +++++++++------ src/util/virpci.h | 26 ++- src/xen/xen_driver.c | 3 +- tests/virhostdevtest.c | 5 +- tests/virpcitest.c | 35 ++-- 9 files changed, 427 insertions(+), 189 deletions(-) -- 2.5.0