pci: Add an API to get IOMMU's min page size and virtual address width

This kind of information is needed by devices implementing ATS in order
to initialize their translation cache.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
Message-Id: <20250520071823.764266-8-clement.mathieu--drif@eviden.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 1114ba85298be088f9a2fd28f3a43c6f87ca7b6a..fc4954ac8134d5c51abe07a679a15efbb033b496 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2970,6 +2970,23 @@ void pci_device_unset_iommu_device(PCIDevice *dev)
     }
 }
 
+int pci_iommu_get_iotlb_info(PCIDevice *dev, uint8_t *addr_width,
+                             uint32_t *min_page_size)
+{
+    PCIBus *bus;
+    PCIBus *iommu_bus;
+    int devfn;
+
+    pci_device_get_iommu_bus_devfn(dev, &bus, &iommu_bus, &devfn);
+    if (iommu_bus && iommu_bus->iommu_ops->get_iotlb_info) {
+        iommu_bus->iommu_ops->get_iotlb_info(iommu_bus->iommu_opaque,
+                                             addr_width, min_page_size);
+        return 0;
+    }
+
+    return -ENODEV;
+}
+
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
 {
     /*

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index c2fe6caa2c6ea5c5098602b6bdd0c19c310de446..d67ffe12db78218f2491b4bce997cd09dd331f92 100644 (file)
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -429,6 +429,19 @@ typedef struct PCIIOMMUOps {
      * @devfn: device and function number of the PCI device.
      */
     void (*unset_iommu_device)(PCIBus *bus, void *opaque, int devfn);
+    /**
+     * @get_iotlb_info: get properties required to initialize a device IOTLB.
+     *
+     * Callback required if devices are allowed to cache translations.
+     *
+     * @opaque: the data passed to pci_setup_iommu().
+     *
+     * @addr_width: the address width of the IOMMU (output parameter).
+     *
+     * @min_page_size: the page size of the IOMMU (output parameter).
+     */
+    void (*get_iotlb_info)(void *opaque, uint8_t *addr_width,
+                           uint32_t *min_page_size);
 } PCIIOMMUOps;
 
 AddressSpace *pci_device_iommu_address_space(PCIDevice *dev);
@@ -436,6 +449,19 @@ bool pci_device_set_iommu_device(PCIDevice *dev, HostIOMMUDevice *hiod,
                                  Error **errp);
 void pci_device_unset_iommu_device(PCIDevice *dev);
 
+/**
+ * pci_iommu_get_iotlb_info: get properties required to initialize a
+ * device IOTLB.
+ *
+ * Returns 0 on success, or a negative errno otherwise.
+ *
+ * @dev: the device that wants to get the information.
+ * @addr_width: the address width of the IOMMU (output parameter).
+ * @min_page_size: the page size of the IOMMU (output parameter).
+ */
+int pci_iommu_get_iotlb_info(PCIDevice *dev, uint8_t *addr_width,
+                             uint32_t *min_page_size);
+
 /**
  * pci_setup_iommu: Initialize specific IOMMU handlers for a PCIBus
  *