pci: Add a memory attribute for pre-translated DMA operations

The address_type bit will be set to PCI_AT_TRANSLATED by devices that
use cached addresses obtained via ATS.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
Message-Id: <20250628180226.133285-2-clement.mathieu--drif@eviden.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

include/exec/memattrs.h

@@ -54,6 +54,9 @@ typedef struct MemTxAttrs {
      */
     unsigned int pid:8;
 
+    /* PCI - IOMMU operations, see PCIAddressType */
+    unsigned int address_type:1;
+
     /*
      * Bus masters which don't specify any attributes will get this
      * (via the MEMTXATTRS_UNSPECIFIED constant), so that we can

include/hw/pci/pci.h

@@ -134,6 +134,15 @@ struct PCIHostDeviceAddress {
     unsigned int function;
 };
 
+/*
+ * Represents the Address Type (AT) field in a PCI request,
+ * see MemTxAttrs.address_type
+ */
+typedef enum PCIAddressType {
+    PCI_AT_UNTRANSLATED = 0, /* Default when no attribute is set */
+    PCI_AT_TRANSLATED = 1,
+} PCIAddressType;
+
 typedef void PCIConfigWriteFunc(PCIDevice *pci_dev,
                                 uint32_t address, uint32_t data, int len);
 typedef uint32_t PCIConfigReadFunc(PCIDevice *pci_dev,