[PULL 10/31] pci: Add an API to get IOMMU's min page size and virtual address width

["Michael S. Tsirkin" <mst@redhat.com>]

From: CLEMENT MATHIEU--DRIF <clement.mathieu--drif@eviden.com>

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>
---
 include/hw/pci/pci.h | 26 ++++++++++++++++++++++++++
 hw/pci/pci.c         | 17 +++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index c2fe6caa2c..d67ffe12db 100644
--- 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
  *
diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 1114ba8529..fc4954ac81 100644
--- 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)
 {
     /*
-- 
MST