pci: set PCI multi-function bit appropriately.

[mirror_qemu.git] / hw / pci.c

diff --git a/hw/pci.c b/hw/pci.c
index 6d1cbb1778c0074c1e442ccb3daed216f4c48def..a3c28738c6a71fe8d4d8fb0c2e9b86a5e0bf015c 100644 (file)
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -584,6 +584,54 @@ static void pci_init_wmask_bridge(PCIDevice *d)
     pci_set_word(d->wmask + PCI_BRIDGE_CONTROL, 0xffff);
 }
 
+static int pci_init_multifunction(PCIBus *bus, PCIDevice *dev)
+{
+    uint8_t slot = PCI_SLOT(dev->devfn);
+    uint8_t func;
+
+    if (dev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
+        dev->config[PCI_HEADER_TYPE] |= PCI_HEADER_TYPE_MULTI_FUNCTION;
+    }
+
+    /*
+     * multifuction bit is interpreted in two ways as follows.
+     *   - all functions must set the bit to 1.
+     *     Example: Intel X53
+     *   - function 0 must set the bit, but the rest function (> 0)
+     *     is allowed to leave the bit to 0.
+     *     Example: PIIX3(also in qemu), PIIX4(also in qemu), ICH10,
+     *
+     * So OS (at least Linux) checks the bit of only function 0,
+     * and doesn't see the bit of function > 0.
+     *
+     * The below check allows both interpretation.
+     */
+    if (PCI_FUNC(dev->devfn)) {
+        PCIDevice *f0 = bus->devices[PCI_DEVFN(slot, 0)];
+        if (f0 && !(f0->cap_present & QEMU_PCI_CAP_MULTIFUNCTION)) {
+            /* function 0 should set multifunction bit */
+            error_report("PCI: single function device can't be populated "
+                         "in function %x.%x", slot, PCI_FUNC(dev->devfn));
+            return -1;
+        }
+        return 0;
+    }
+
+    if (dev->cap_present & QEMU_PCI_CAP_MULTIFUNCTION) {
+        return 0;
+    }
+    /* function 0 indicates single function, so function > 0 must be NULL */
+    for (func = 1; func < PCI_FUNC_MAX; ++func) {
+        if (bus->devices[PCI_DEVFN(slot, func)]) {
+            error_report("PCI: %x.0 indicates single function, "
+                         "but %x.%x is already populated.",
+                         slot, slot, func);
+            return -1;
+        }
+    }
+    return 0;
+}
+
 static void pci_config_alloc(PCIDevice *pci_dev)
 {
     int config_size = pci_config_size(pci_dev);
@@ -637,6 +685,10 @@ static PCIDevice *do_pci_register_device(PCIDevice *pci_dev, PCIBus *bus,
     if (is_bridge) {
         pci_init_wmask_bridge(pci_dev);
     }
+    if (pci_init_multifunction(bus, pci_dev)) {
+        pci_config_free(pci_dev);
+        return NULL;
+    }
 
     if (!config_read)
         config_read = pci_default_read_config;