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| author | Matthew Rosato <mjrosato@linux.ibm.com> | 2020-11-16 16:42:35 -0500 |
|---|---|---|
| committer | Cornelia Huck <cohuck@redhat.com> | 2020-11-18 16:57:49 +0100 |
| commit | e67ad058e45aa8b23e9b94e793b9fcf66e70ebb0 (patch) | |
| tree | 2f766d0b039d5ae0dc0e0ab4c35fce9e5f811db7 /hw/s390x | |
| parent | e2c6cd567422bfa563be026b9741a1854aecdc06 (diff) | |
| download | qemu-e67ad058e45aa8b23e9b94e793b9fcf66e70ebb0.zip qemu-e67ad058e45aa8b23e9b94e793b9fcf66e70ebb0.tar.gz qemu-e67ad058e45aa8b23e9b94e793b9fcf66e70ebb0.tar.bz2 | |
s390x/pci: Unregister listeners before destroying IOMMU address space
Hot-unplugging a vfio-pci device on s390x causes a QEMU crash:
qemu-system-s390x: ../softmmu/memory.c:2772:
do_address_space_destroy: Assertion `QTAILQ_EMPTY(&as->listeners)' failed.
In s390, the IOMMU address space is freed during device unplug but the
associated vfio-pci device may not yet be finalized and therefore may
still have a listener registered to the IOMMU address space.
Commit a2166410ad74 ("spapr_pci: Unregister listeners before destroying
the IOMMU address space") previously resolved this issue for spapr_pci.
We are now seeing this in s390x; it would seem the possibility for this
issue was already present but based on a bisect commit 2d24a6466154
("device-core: use RCU for list of children of a bus") has now changed
the timing such that it is now readily reproducible.
Add logic to ensure listeners are removed before destroying the address
space.
Reported-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1605562955-21152-1-git-send-email-mjrosato@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Diffstat (limited to 'hw/s390x')
| -rw-r--r-- | hw/s390x/s390-pci-bus.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c index 48a3be8..e0dc20c 100644 --- a/hw/s390x/s390-pci-bus.c +++ b/hw/s390x/s390-pci-bus.c @@ -732,6 +732,13 @@ static void s390_pci_iommu_free(S390pciState *s, PCIBus *bus, int32_t devfn) table->iommu[PCI_SLOT(devfn)] = NULL; g_hash_table_destroy(iommu->iotlb); + /* + * An attached PCI device may have memory listeners, eg. VFIO PCI. + * The associated subregion will already have been unmapped in + * s390_pci_iommu_disable in response to the guest deconfigure request. + * Remove the listeners now before destroying the address space. + */ + address_space_remove_listeners(&iommu->as); address_space_destroy(&iommu->as); object_unparent(OBJECT(&iommu->mr)); object_unparent(OBJECT(iommu)); |