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virtio-iommu: Remove probe_done 

Now we have switched to PCIIOMMUOps to convey host IOMMU information,
the host reserved regions are transmitted when the PCIe topology is
built. This happens way before the virtio-iommu driver calls the probe
request. So let's remove the probe_done flag that allowed to check
the probe was not done before the IOMMU MR got enabled. Besides this
probe_done flag had a flaw wrt migration since it was not saved/restored.

The only case at risk is if 2 devices were plugged to a
PCIe to PCI bridge and thus aliased. First of all we
discovered in the past this case was not properly supported for
neither SMMU nor virtio-iommu on guest kernel side: see

[RFC] virtio-iommu: Take into account possible aliasing in virtio_iommu_mr()
https://lore.kernel.org/all/20230116124709.793084-1-eric.auger@redhat.com/

If this were supported by the guest kernel, it is unclear what the call
sequence would be from a virtio-iommu driver point of view.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Message-Id: <20240716094619.1713905-3-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 11:45:04 +02:00 committed by Michael S. Tsirkin
parent 935c391418
commit 3745768918
2 changed files with 0 additions and 4 deletions
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3
hw/virtio/virtio-iommu.c
View File

@ -555,8 +555,6 @@ static int virtio_iommu_set_host_iova_ranges(VirtIOIOMMU *s, PCIBus *bus,
current_ranges = sdev->host_resv_ranges;
g_assert(!sdev->probe_done);
/* check that each new resv region is included in an existing one */
if (sdev->host_resv_ranges) {
range_inverse_array(iova_ranges,
@ -956,7 +954,6 @@ static int virtio_iommu_probe(VirtIOIOMMU *s,
}
buf += count;
free -= count;
sdev->probe_done = true;
return VIRTIO_IOMMU_S_OK;
}

1
include/hw/virtio/virtio-iommu.h
View File

@ -43,7 +43,6 @@ typedef struct IOMMUDevice {
MemoryRegion bypass_mr; /* The alias of shared memory MR */
GList *resv_regions;
GList *host_resv_ranges;
bool probe_done;
} IOMMUDevice;
typedef struct IOMMUPciBus {