On 7/16/24 11:45, Eric Auger wrote:
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.au...@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.au...@redhat.com>
Reviewed-by: Cédric Le Goater <c...@redhat.com>
Thanks,
C.
---
include/hw/virtio/virtio-iommu.h | 1 -
hw/virtio/virtio-iommu.c | 3 ---
2 files changed, 4 deletions(-)
diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h
index bdb3da72d0..7db4210b16 100644
--- a/include/hw/virtio/virtio-iommu.h
+++ b/include/hw/virtio/virtio-iommu.h
@@ -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 {
diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c
index 4e34dacd6e..2c54c0d976 100644
--- a/hw/virtio/virtio-iommu.c
+++ b/hw/virtio/virtio-iommu.c
@@ -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;
}
