[Qemu-devel] [PATCH v4 08/10] vfio: vote the function 0 to do host bus reset when aer occurred

[Cao jin]

From: Chen Fan <chen.fan.f...@cn.fujitsu.com>

Due to all devices assigned to VM on the same way as host if enable
aer, so we can easily do the hot reset by selecting the function #0
to do the hot reset.

Signed-off-by: Chen Fan <chen.fan.f...@cn.fujitsu.com>
---
 hw/vfio/pci.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vfio/pci.h |  2 ++
 2 files changed, 52 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 9902c87..718cde7 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1900,6 +1900,8 @@ static void vfio_check_hot_bus_reset(VFIOPCIDevice *vdev, 
Error **errp)
     /* List all affected devices by bus reset */
     devices = &info->devices[0];
 
+    vdev->single_depend_dev = (info->count == 1);
+
     /* Verify that we have all the groups required */
     for (i = 0; i < info->count; i++) {
         PCIHostDeviceAddress host;
@@ -2608,11 +2610,36 @@ static void vfio_put_device(VFIOPCIDevice *vdev)
 static void vfio_err_notifier_handler(void *opaque)
 {
     VFIOPCIDevice *vdev = opaque;
+    PCIDevice *pdev = &vdev->pdev;
 
     if (!event_notifier_test_and_clear(&vdev->err_notifier)) {
         return;
     }
 
+    if (vdev->features & VFIO_FEATURE_ENABLE_AER) {
+        VFIOPCIDevice *tmp;
+        PCIDevice *dev;
+        int devfn;
+
+        /*
+         * If one device has aer capability on a bus, when aer occurred,
+         * we should notify all devices on the bus there was an aer arrived,
+         * then we are able to vote the device #0 to do host bus reset.
+         */
+        for (devfn = 0; devfn < 8; devfn++) {
+            dev = pci_find_device(pdev->bus, pci_bus_num(pdev->bus),
+                      PCI_DEVFN(PCI_SLOT(pdev->devfn), devfn));
+            if (!dev) {
+                continue;
+            }
+            if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
+                continue;
+            }
+            tmp = DO_UPCAST(VFIOPCIDevice, pdev, dev);
+            tmp->aer_occurred = true;
+        }
+    }
+
     /*
      * TBD. Retrieve the error details and decide what action
      * needs to be taken. One of the actions could be to pass
@@ -3075,6 +3102,29 @@ static void vfio_pci_reset(DeviceState *dev)
 
     trace_vfio_pci_reset(vdev->vbasedev.name);
 
+    if (vdev->aer_occurred) {
+        PCIDevice *br = pci_bridge_get_device(pdev->bus);
+
+        if (br &&
+            (pci_get_word(br->config + PCI_BRIDGE_CONTROL) &
+             PCI_BRIDGE_CTL_BUS_RESET)) {
+            /* simply voting the function 0 to do hot bus reset */
+            if (pci_get_function_0(pdev) == pdev) {
+                if (vdev->features & VFIO_FEATURE_ENABLE_AER) {
+                    vfio_pci_hot_reset(vdev, vdev->single_depend_dev);
+                } else {
+                    /* if this device has not AER capability, code
+                     * coming here indicates there is another function
+                     * on the bus has AER capability.
+                     * */
+                    vfio_pci_hot_reset(vdev, false);
+                }
+            }
+            vdev->aer_occurred = false;
+            return;
+        }
+    }
+
     vfio_pci_pre_reset(vdev);
 
     if (vdev->resetfn && !vdev->resetfn(vdev)) {
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index db7c6d5..17c75b8 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -143,6 +143,8 @@ typedef struct VFIOPCIDevice {
     bool no_kvm_intx;
     bool no_kvm_msi;
     bool no_kvm_msix;
+    bool aer_occurred;
+    bool single_depend_dev;
 } VFIOPCIDevice;
 
 uint32_t vfio_pci_read_config(PCIDevice *pdev, uint32_t addr, int len);
-- 
1.9.3