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Revert "virtio-iommu: Clear IOMMUDevice when VFIO device is unplugged"

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This reverts commit 1b889d6e39c32d709f1114699a014b381bcf1cb1.
There are different problems with that tentative fix:
- Some resources are left dangling (resv_regions,
  host_resv_ranges) and memory subregions are left attached to
  the root MR although freed as embedded in the sdev IOMMUDevice.
  Finally the sdev->as is not destroyed and associated listeners
  are left.
- Even when fixing the above we observe a memory corruption
  associated with the deallocation of the IOMMUDevice. This can
  be observed when a VFIO device is hotplugged, hot-unplugged
  and a system reset is issued. At this stage we have not been
  able to identify the root cause (IOMMU MR or as structs beeing
  overwritten and used later on?).
- Another issue is HostIOMMUDevice are indexed by non aliased
  BDF whereas the IOMMUDevice is indexed by aliased BDF - yes the
  current naming is really misleading -. Given the state of the
  code I don't think the virtio-iommu device works in non
  singleton group case though.

So let's revert the patch for now. This means the IOMMU MR/as survive
the hotunplug. This is what is done in the intel_iommu for instance.
It does not sound very logical to keep those but currently there is
no symetric function to pci_device_iommu_address_space().

probe_done issue will be handled in a subsequent patch. Also
resv_regions and host_resv_regions will be deallocated separately.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20240716094619.1713905-2-eric.auger@redhat.com>
Tested-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Cédric Le Goater <clg@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Eric Auger 2024-07-16 11:45:03 +02:00 committed by Michael S. Tsirkin
parent 242da18082
commit 935c391418
1 changed files with 0 additions and 21 deletions
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21
hw/virtio/virtio-iommu.c
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@ -467,26 +467,6 @@ static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque,
return &sdev->as;
}
static void virtio_iommu_device_clear(VirtIOIOMMU *s, PCIBus *bus, int devfn)
{
IOMMUPciBus *sbus = g_hash_table_lookup(s->as_by_busptr, bus);
IOMMUDevice *sdev;
if (!sbus) {
return;
}
sdev = sbus->pbdev[devfn];
if (!sdev) {
return;
}
g_list_free_full(sdev->resv_regions, g_free);
sdev->resv_regions = NULL;
g_free(sdev);
sbus->pbdev[devfn] = NULL;
}
static gboolean hiod_equal(gconstpointer v1, gconstpointer v2)
{
const struct hiod_key *key1 = v1;
@ -728,7 +708,6 @@ virtio_iommu_unset_iommu_device(PCIBus *bus, void *opaque, int devfn)
}
g_hash_table_remove(viommu->host_iommu_devices, &key);
virtio_iommu_device_clear(viommu, bus, devfn);
}
static const PCIIOMMUOps virtio_iommu_ops = {