[Qemu-devel] [PATCH 3/4] hw/virtio: fix Link Control Register for PCI Express virtio devices

[Marcel Apfelbaum <marcel@redhat.com>]

Make several Link Control Register flags writable to conform
with the PCI Express spec.

Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
---
 hw/pci/pcie.c          | 14 ++++++++++++++
 hw/virtio/virtio-pci.c |  3 +++
 include/hw/pci/pcie.h  |  3 +++
 3 files changed, 20 insertions(+)

diff --git a/hw/pci/pcie.c b/hw/pci/pcie.c
index 62c1def..a596400 100644
--- a/hw/pci/pcie.c
+++ b/hw/pci/pcie.c
@@ -220,6 +220,20 @@ void pcie_cap_deverr_reset(PCIDevice *dev)
                                  PCI_EXP_DEVCTL_FERE | PCI_EXP_DEVCTL_URRE);
 }
 
+void pcie_cap_lnkctl_init(PCIDevice *dev)
+{
+    uint32_t pos = dev->exp.exp_cap;
+    pci_long_test_and_set_mask(dev->wmask + pos + PCI_EXP_LNKCTL,
+                               PCI_EXP_LNKCTL_CCC | PCI_EXP_LNKCTL_ES);
+}
+
+void pcie_cap_lnkctl_reset(PCIDevice *dev)
+{
+    uint8_t *lnkctl = dev->config + dev->exp.exp_cap + PCI_EXP_LNKCTL;
+    pci_long_test_and_clear_mask(lnkctl,
+                                 PCI_EXP_LNKCTL_CCC | PCI_EXP_LNKCTL_ES);
+}
+
 static void hotplug_event_update_event_status(PCIDevice *dev)
 {
     uint32_t pos = dev->exp.exp_cap;
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index da2124f..66a5bf3 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1804,6 +1804,8 @@ static void virtio_pci_realize(PCIDevice *pci_dev, Error **errp)
         pci_set_word(pci_dev->config + pos + PCI_PM_PMC, 0x3);
         /* Init error enabling flags */
         pcie_cap_deverr_init(pci_dev);
+        /* Init Link Control Register */
+        pcie_cap_lnkctl_init(pci_dev);
     } else {
         /*
          * make future invocations of pci_is_express() return false
@@ -1843,6 +1845,7 @@ static void virtio_pci_reset(DeviceState *qdev)
 
     if (pci_is_express(dev)) {
         pcie_cap_deverr_reset(dev);
+        pcie_cap_lnkctl_reset(dev);
     }
 }
 
diff --git a/include/hw/pci/pcie.h b/include/hw/pci/pcie.h
index 056d25e..7d6611a 100644
--- a/include/hw/pci/pcie.h
+++ b/include/hw/pci/pcie.h
@@ -93,6 +93,9 @@ uint8_t pcie_cap_flags_get_vector(PCIDevice *dev);
 void pcie_cap_deverr_init(PCIDevice *dev);
 void pcie_cap_deverr_reset(PCIDevice *dev);
 
+void pcie_cap_lnkctl_init(PCIDevice *dev);
+void pcie_cap_lnkctl_reset(PCIDevice *dev);
+
 void pcie_cap_slot_init(PCIDevice *dev, uint16_t slot);
 void pcie_cap_slot_reset(PCIDevice *dev);
 void pcie_cap_slot_write_config(PCIDevice *dev,
-- 
2.5.5