pci: move acpi-index uniqueness check to generic PCI device code

acpi-index is now working with non-hotpluggable buses
(pci/q35 machine hostbridge), it can be used even if
ACPI PCI hotplug is disabled and as result acpi-index
uniqueness check will be omitted (since the check is
done by ACPI PCI hotplug handler, which isn't wired
when ACPI PCI hotplug is disabled).
Move check and related code to generic PCIDevice so it
would be independent of ACPI PCI hotplug.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20230302161543.286002-30-imammedo@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 57 insertions, 0 deletions

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 034fe49..def5000 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -95,6 +95,21 @@ static const VMStateDescription vmstate_pcibus = {
     }
 };
 
+static gint g_cmp_uint32(gconstpointer a, gconstpointer b, gpointer user_data)
+{
+    return a - b;
+}
+
+static GSequence *pci_acpi_index_list(void)
+{
+    static GSequence *used_acpi_index_list;
+
+    if (!used_acpi_index_list) {
+        used_acpi_index_list = g_sequence_new(NULL);
+    }
+    return used_acpi_index_list;
+}
+
 static void pci_init_bus_master(PCIDevice *pci_dev)
 {
     AddressSpace *dma_as = pci_device_iommu_address_space(pci_dev);
@@ -1246,6 +1261,17 @@ static void pci_qdev_unrealize(DeviceState *dev)
     do_pci_unregister_device(pci_dev);
 
     pci_dev->msi_trigger = NULL;
+
+    /*
+     * clean up acpi-index so it could reused by another device
+     */
+    if (pci_dev->acpi_index) {
+        GSequence *used_indexes = pci_acpi_index_list();
+
+        g_sequence_remove(g_sequence_lookup(used_indexes,
+                          GINT_TO_POINTER(pci_dev->acpi_index),
+                          g_cmp_uint32, NULL));
+    }
 }
 
 void pci_register_bar(PCIDevice *pci_dev, int region_num,
@@ -2005,6 +2031,8 @@ PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
     return bus->devices[devfn];
 }
 
+#define ONBOARD_INDEX_MAX (16 * 1024 - 1)
+
 static void pci_qdev_realize(DeviceState *qdev, Error **errp)
 {
     PCIDevice *pci_dev = (PCIDevice *)qdev;
@@ -2014,6 +2042,35 @@ static void pci_qdev_realize(DeviceState *qdev, Error **errp)
     bool is_default_rom;
     uint16_t class_id;
 
+    /*
+     * capped by systemd (see: udev-builtin-net_id.c)
+     * as it's the only known user honor it to avoid users
+     * misconfigure QEMU and then wonder why acpi-index doesn't work
+     */
+    if (pci_dev->acpi_index > ONBOARD_INDEX_MAX) {
+        error_setg(errp, "acpi-index should be less or equal to %u",
+                   ONBOARD_INDEX_MAX);
+        return;
+    }
+
+    /*
+     * make sure that acpi-index is unique across all present PCI devices
+     */
+    if (pci_dev->acpi_index) {
+        GSequence *used_indexes = pci_acpi_index_list();
+
+        if (g_sequence_lookup(used_indexes,
+                              GINT_TO_POINTER(pci_dev->acpi_index),
+                              g_cmp_uint32, NULL)) {
+            error_setg(errp, "a PCI device with acpi-index = %" PRIu32
+                       " already exist", pci_dev->acpi_index);
+            return;
+        }
+        g_sequence_insert_sorted(used_indexes,
+                                 GINT_TO_POINTER(pci_dev->acpi_index),
+                                 g_cmp_uint32, NULL);
+    }
+
     if (pci_dev->romsize != -1 && !is_power_of_2(pci_dev->romsize)) {
         error_setg(errp, "ROM size %u is not a power of two", pci_dev->romsize);
         return;