[Qemu-devel] [PATCH 05/10] vfio: add check host bus reset is support or not

[Cao jin]

From: Chen Fan <address@hidden>

when boot up a VM that assigning vfio devices with aer enabled, we
must check the vfio device whether support host bus reset. because
when one error occur. OS driver always recover the device by do a
bus reset, in order to recover the vfio device, qemu must to do a
host bus reset to reset the device to default status. and for all
affected devices by the bus reset. we must check them whether all
are assigned to the VM.

Signed-off-by: Chen Fan <address@hidden>
---
 hw/vfio/pci.c | 234 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 hw/vfio/pci.h |   1 +
 2 files changed, 228 insertions(+), 7 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 8ec9b25..54032d0 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1868,6 +1868,214 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, 
uint8_t pos)
     return 0;
 }
 
+static bool vfio_pci_host_slot_match(PCIHostDeviceAddress *host1,
+                                     PCIHostDeviceAddress *host2)
+{
+    return (host1->domain == host2->domain && host1->bus == host2->bus &&
+            host1->slot == host2->slot);
+}
+
+static bool vfio_pci_host_match(PCIHostDeviceAddress *host1,
+                                PCIHostDeviceAddress *host2)
+{
+    return (vfio_pci_host_slot_match(host1, host2) &&
+            host1->function == host2->function);
+}
+
+struct VFIODeviceFind {
+    PCIDevice *pdev;
+    bool found;
+};
+
+static void vfio_check_device_noreset(PCIBus *bus, PCIDevice *pdev,
+                                      void *opaque)
+{
+    DeviceState *dev = DEVICE(pdev);
+    DeviceClass *dc = DEVICE_GET_CLASS(dev);
+    VFIOPCIDevice *vdev;
+    struct VFIODeviceFind *find = opaque;
+
+    if (find->found) {
+        return;
+    }
+
+    if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
+        if (!dc->reset) {
+            goto found;
+        }
+        return;
+    }
+    vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
+    if (!(vdev->features & VFIO_FEATURE_ENABLE_AER) &&
+        !vdev->vbasedev.reset_works) {
+        goto found;
+    }
+
+    return;
+found:
+    find->pdev = pdev;
+    find->found = true;
+}
+
+static void device_find(PCIBus *bus, PCIDevice *pdev, void *opaque)
+{
+    struct VFIODeviceFind *find = opaque;
+
+    if (find->found) {
+        return;
+    }
+
+    if (pdev == find->pdev) {
+        find->found = true;
+    }
+}
+
+static int vfio_check_host_bus_reset(VFIOPCIDevice *vdev)
+{
+    PCIBus *bus = vdev->pdev.bus;
+    struct vfio_pci_hot_reset_info *info = NULL;
+    struct vfio_pci_dependent_device *devices;
+    VFIOGroup *group;
+    struct VFIODeviceFind find;
+    int ret, i;
+
+    ret = vfio_get_hot_reset_info(vdev, &info);
+    if (ret) {
+        error_report("vfio: Cannot enable AER for device %s,"
+                     " device does not support hot reset.",
+                     vdev->vbasedev.name);
+        return ret;
+    }
+
+    ret = -1;
+    /* List all affected devices by bus reset */
+    devices = &info->devices[0];
+
+    /* Verify that we have all the groups required */
+    for (i = 0; i < info->count; i++) {
+        PCIHostDeviceAddress host;
+        VFIOPCIDevice *tmp;
+        VFIODevice *vbasedev_iter;
+        bool found = false;
+
+        host.domain = devices[i].segment;
+        host.bus = devices[i].bus;
+        host.slot = PCI_SLOT(devices[i].devfn);
+        host.function = PCI_FUNC(devices[i].devfn);
+
+        /* Skip the current device */
+        if (vfio_pci_host_match(&host, &vdev->host)) {
+            continue;
+        }
+
+        /* Ensure we own the group of the affected device */
+        QLIST_FOREACH(group, &vfio_group_list, next) {
+            if (group->groupid == devices[i].group_id) {
+                break;
+            }
+        }
+
+        if (!group) {
+            error_report("vfio: Cannot enable AER for device %s, "
+                         "depends on group %d which is not owned.",
+                         vdev->vbasedev.name, devices[i].group_id);
+            goto out;
+        }
+
+        /* Ensure affected devices for reset behind the bus */
+        QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
+            if (vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
+                continue;
+            }
+            tmp = container_of(vbasedev_iter, VFIOPCIDevice, vbasedev);
+            if (vfio_pci_host_match(&host, &tmp->host)) {
+                PCIDevice *pci = PCI_DEVICE(tmp);
+
+                /*
+                 * AER errors may be broadcast to all functions of a multi-
+                 * function endpoint.  If any of those sibling functions are
+                 * also assigned, they need to have AER enabled or else an
+                 * error may continue to cause a vm_stop condition.  IOW,
+                 * AER setup of this function would be pointless.
+                 */
+                if (vfio_pci_host_slot_match(&vdev->host, &tmp->host) &&
+                    !(tmp->features & VFIO_FEATURE_ENABLE_AER)) {
+                    error_report("vfio: Cannot enable AER for device %s, on 
same slot"
+                                 " the dependent device %s which does not 
enable AER.",
+                                 vdev->vbasedev.name, tmp->vbasedev.name);
+                    goto out;
+                }
+
+                find.pdev = pci;
+                find.found = false;
+                pci_for_each_device(bus, pci_bus_num(bus),
+                                    device_find, &find);
+                if (!find.found) {
+                    error_report("vfio: Cannot enable AER for device %s, "
+                                 "the dependent device %s is not under the 
same bus",
+                                 vdev->vbasedev.name, tmp->vbasedev.name);
+                    goto out;
+                }
+                found = true;
+                break;
+            }
+        }
+
+        /* Ensure all affected devices assigned to VM */
+        if (!found) {
+            error_report("vfio: Cannot enable AER for device %s, "
+                         "the dependent device %04x:%02x:%02x.%x "
+                         "is not assigned to VM.",
+                         vdev->vbasedev.name, host.domain, host.bus,
+                         host.slot, host.function);
+            goto out;
+        }
+    }
+
+    /*
+     * Check the all pci devices on or below the target bus
+     * have a reset mechanism at least.
+     */
+    find.pdev = NULL;
+    find.found = false;
+    pci_for_each_device(bus, pci_bus_num(bus),
+                        vfio_check_device_noreset, &find);
+    if (find.found) {
+        error_report("vfio: Cannot enable AER for device %s, "
+                     "the affected device %s does not have a reset mechanism.",
+                     vdev->vbasedev.name, find.pdev->name);
+        goto out;
+    }
+
+    ret = 0;
+out:
+    g_free(info);
+    return ret;
+}
+
+static int vfio_check_devices_host_bus_reset(void)
+{
+    VFIOGroup *group;
+    VFIODevice *vbasedev;
+    VFIOPCIDevice *vdev;
+
+    /* Check All vfio-pci devices if have bus reset capability */
+    QLIST_FOREACH(group, &vfio_group_list, next) {
+        QLIST_FOREACH(vbasedev, &group->device_list, next) {
+            if (vbasedev->type != VFIO_DEVICE_TYPE_PCI) {
+                continue;
+            }
+            vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+            if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
+                vfio_check_host_bus_reset(vdev)) {
+                return -1;
+            }
+        }
+    }
+
+    return 0;
+}
+
 static int vfio_setup_aer(VFIOPCIDevice *vdev, uint8_t cap_ver,
                           int pos, uint16_t size)
 {
@@ -2047,13 +2255,6 @@ static void vfio_pci_post_reset(VFIOPCIDevice *vdev)
     vfio_intx_enable(vdev);
 }
 
-static bool vfio_pci_host_match(PCIHostDeviceAddress *host1,
-                                PCIHostDeviceAddress *host2)
-{
-    return (host1->domain == host2->domain && host1->bus == host2->bus &&
-            host1->slot == host2->slot && host1->function == host2->function);
-}
-
 static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool single)
 {
     VFIOGroup *group;
@@ -2559,6 +2760,20 @@ static void vfio_unregister_req_notifier(VFIOPCIDevice 
*vdev)
     vdev->req_enabled = false;
 }
 
+static void vfio_pci_machine_done_notify(Notifier *notifier, void *unused)
+{
+    int ret;
+
+    ret = vfio_check_devices_host_bus_reset();
+    if (ret) {
+        exit(1);
+    }
+}
+
+static Notifier machine_notifier = {
+    .notify = vfio_pci_machine_done_notify,
+};
+
 static int vfio_initfn(PCIDevice *pdev)
 {
     VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
@@ -2905,6 +3120,11 @@ static const TypeInfo vfio_pci_dev_info = {
 static void register_vfio_pci_dev_type(void)
 {
     type_register_static(&vfio_pci_dev_info);
+    /*
+     * Register notifier when machine init is done, since we need
+     * check the configration manner after all vfio device are inited.
+     */
+    qemu_add_machine_init_done_notifier(&machine_notifier);
 }
 
 type_init(register_vfio_pci_dev_type)
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h
index e0c53f2..aff46c2 100644
--- a/hw/vfio/pci.h
+++ b/hw/vfio/pci.h
@@ -15,6 +15,7 @@
 #include "qemu-common.h"
 #include "exec/memory.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
 #include "hw/pci/pci_bridge.h"
 #include "hw/vfio/vfio-common.h"
 #include "qemu/event_notifier.h"
-- 
1.9.3