Current amd_iommu enables the iommu_nodma address space when pt_supported
flag is on. This causes device to bypass the IOMMU and use untranslated
address to perform DMA when guest kernel uses DMA mode, resulting in
failure to setup the devices in the guest.
Fix the issue by always enabling amdvi_dev_as->iommu, which is explicitly
created as an IOMMU memory region (i.e. a memory region with mr->is_iommu
== true), and it is meant to support DMA remapping. It is relying on the
"side effect" that VFIO will try to register notifiers for memory regions
that are an "IOMMU" (i.e. pass the check in memory_region_is_iommu()),
and later fail when trying to register the notifier.
Fixes: c1f46999ef506 ("amd_iommu: Add support for pass though mode")
Signed-off-by: Sairaj Kodilkar <sarun...@amd.com>
Reviewed-by: Vasant Hegde <vasant.he...@amd.com>
---
hw/i386/amd_iommu.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index 5f9b95279997..df8ba5d39ada 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -1426,7 +1426,6 @@ static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus,
void *opaque, int devfn)
AMDVIState *s = opaque;
AMDVIAddressSpace **iommu_as, *amdvi_dev_as;
int bus_num = pci_bus_num(bus);
- X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
iommu_as = s->address_spaces[bus_num];
@@ -1486,15 +1485,8 @@ static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus,
void *opaque, int devfn)
AMDVI_INT_ADDR_FIRST,
&amdvi_dev_as->iommu_ir, 1);
- if (!x86_iommu->pt_supported) {
- memory_region_set_enabled(&amdvi_dev_as->iommu_nodma, false);
- memory_region_set_enabled(MEMORY_REGION(&amdvi_dev_as->iommu),
- true);
- } else {
- memory_region_set_enabled(MEMORY_REGION(&amdvi_dev_as->iommu),
- false);
- memory_region_set_enabled(&amdvi_dev_as->iommu_nodma, true);
- }
+ memory_region_set_enabled(&amdvi_dev_as->iommu_nodma, false);
+ memory_region_set_enabled(MEMORY_REGION(&amdvi_dev_as->iommu), true);
}
return &iommu_as[devfn]->as;
}
--
2.34.1
