[05/18] amd_iommu: Toggle memory regions based on address translation mode

Commit Message

Alejandro Jimenez April 14, 2025, 2:02 a.m. UTC

Enable the appropriate memory region for an address space depending on
the address translation mode selected for it. This is currently based on
a generic x86 IOMMMU property, and only done during the address space
initialization. Extract the code into a helper and toggle the regions
based on whether DMA remapping is available as a global capability, and
if the specific address space is using address translation.

Signed-off-by: Alejandro Jimenez <[e-mail]>
---
 hw/i386/amd_iommu.c | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

Patch

diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
index ad5869e72fdc..3f9aa2cc8d31 100644
--- a/hw/i386/amd_iommu.c
+++ b/hw/i386/amd_iommu.c
@@ -1529,13 +1529,31 @@  static const MemoryRegionOps amdvi_ir_ops = {
     }
 };
 
+/*
+ * Toggle between address translation and passthrough modes by enabling the
+ * corresponding memory regions.
+ */
+static void amdvi_switch_address_space(AMDVIAddressSpace *amdvi_as)
+{
+    AMDVIState *s = amdvi_as->iommu_state;
+
+    if (s->dma_remap && amdvi_as->addr_translation) {
+        /* Enabling DMA region */
+        memory_region_set_enabled(&amdvi_as->iommu_nodma, false);
+        memory_region_set_enabled(MEMORY_REGION(&amdvi_as->iommu), true);
+    } else {
+        /* Disabling DMA region, using passthrough */
+        memory_region_set_enabled(MEMORY_REGION(&amdvi_as->iommu), false);
+        memory_region_set_enabled(&amdvi_as->iommu_nodma, true);
+    }
+}
+
 static AddressSpace *amdvi_host_dma_iommu(PCIBus *bus, void *opaque, int devfn)
 {
     char name[128];
     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];
 
@@ -1595,15 +1613,7 @@  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);
-        }
+        amdvi_switch_address_space(amdvi_dev_as);
     }
     return &iommu_as[devfn]->as;
 }