[Qemu-devel] [PATCH v2 3/5] pci/pcie: make pci_find_device() ARI aware.

[Isaku Yamahata]

make pci_find_device() ARI aware.

Signed-off-by: Isaku Yamahata <yamah...@valinux.co.jp>
---
 hw/pci.c  |    6 ++++++
 hw/pci.h  |   42 ++++++++++++++++++++++++++++++++++++++++++
 hw/pcie.c |   13 -------------
 hw/pcie.h |    1 -
 4 files changed, 48 insertions(+), 14 deletions(-)

diff --git a/hw/pci.c b/hw/pci.c
index 899b23d..471d4d7 100644
--- a/hw/pci.c
+++ b/hw/pci.c
@@ -1604,11 +1604,17 @@ PCIBus *pci_find_bus(PCIBus *bus, int bus_num)
 
 PCIDevice *pci_find_device(PCIBus *bus, int bus_num, uint8_t devfn)
 {
+    PCIDevice *d;
     bus = pci_find_bus(bus, bus_num);
 
     if (!bus)
         return NULL;
 
+    d = bus->parent_dev;
+    /* ARI: See the comment above the pcie_check_slot() for details */
+    if (d && !pcie_check_slot(d, devfn)) {
+        return NULL;
+    }
     return bus->devices[devfn];
 }
 
diff --git a/hw/pci.h b/hw/pci.h
index 72025b1..2266a47 100644
--- a/hw/pci.h
+++ b/hw/pci.h
@@ -467,4 +467,46 @@ static inline uint32_t pci_config_size(const PCIDevice *d)
     return pci_is_express(d) ? PCIE_CONFIG_SPACE_SIZE : PCI_CONFIG_SPACE_SIZE;
 }
 
+/*
+ * Although this function should be in pcie.h ideally,
+ * it is here because pci.h depends on pcie.h and this function depdnds
+ * on pci.h
+ *
+ * 6.13 Alternative routing-ID Interpretation(ARI)
+ * 7.8.16 Device control 2 register
+ *   ARI forwarding Enable
+ *
+ * With PCI Express Endpoints, there's a single device behind
+ * each downstream port bus, and bits 3:7 of the function number get
+ * encoded in the slot number (the Express spec calls it the Device
+ * Number). This allows > 8 functions, but
+ * these extended functions are only accessible when the
+ * Alternative routing-ID Interpretation (ARI)
+ * capability is enabled in the root/downstream port. With that capability
+ * disabled the port enforces the Device Number field being 0.
+ */
+static inline bool pcie_check_slot(const PCIDevice *dev, uint8_t devfn)
+{
+    uint8_t type;
+
+    if (!pci_is_express(dev)) {
+        return true;
+    }
+
+    type = pcie_cap_get_type(dev);
+    if (!(type == PCI_EXP_TYPE_ROOT_PORT ||
+          type == PCI_EXP_TYPE_DOWNSTREAM)) {
+        return true;
+    }
+
+    if (!PCI_SLOT(devfn)) {
+        /* With ARI, this means function < 8.
+           functions < 8 are always accesible. */
+        return true;
+    }
+
+    return pci_get_long(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2) &
+        PCI_EXP_DEVCTL2_ARI;
+}
+
 #endif
diff --git a/hw/pcie.c b/hw/pcie.c
index 6a113a9..006e2a8 100644
--- a/hw/pcie.c
+++ b/hw/pcie.c
@@ -424,19 +424,6 @@ void pcie_cap_ari_reset(PCIDevice *dev)
     pci_long_test_and_clear_mask(devctl2, PCI_EXP_DEVCTL2_ARI);
 }
 
-bool pcie_cap_is_ari_enabled(const PCIDevice *dev)
-{
-    if (!pci_is_express(dev)) {
-        return false;
-    }
-    if (!dev->exp.exp_cap) {
-        return false;
-    }
-
-    return pci_get_long(dev->config + dev->exp.exp_cap + PCI_EXP_DEVCTL2) &
-        PCI_EXP_DEVCTL2_ARI;
-}
-
 /**************************************************************************
  * pci express extended capability allocation functions
  * uint16_t ext_cap_id (16 bit)
diff --git a/hw/pcie.h b/hw/pcie.h
index bc909e2..ee3988f 100644
--- a/hw/pcie.h
+++ b/hw/pcie.h
@@ -119,7 +119,6 @@ void pcie_cap_flr_write_config(PCIDevice *dev,
 
 void pcie_cap_ari_init(PCIDevice *dev);
 void pcie_cap_ari_reset(PCIDevice *dev);
-bool pcie_cap_is_ari_enabled(const PCIDevice *dev);
 
 /* PCI express extended capability helper functions */
 uint16_t pcie_find_capability(PCIDevice *dev, uint16_t cap_id);
-- 
1.7.1.1