[Qemu-devel] [RFC v9 11/18] vfio: add check host bus reset is support or not

[Chen Fan]

we introduce a has_bus_reset capability to sign the vfio
devices if support host bus reset.

Signed-off-by: Chen Fan <address@hidden>
---
 hw/vfio/pci.c | 169 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 169 insertions(+)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 06006ce..97af143 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -32,6 +32,7 @@
 #include "hw/pci/msi.h"
 #include "hw/pci/msix.h"
 #include "hw/pci/pci.h"
+#include "hw/pci/pci_bus.h"
 #include "hw/pci/pci_bridge.h"
 #include "qemu-common.h"
 #include "qemu/error-report.h"
@@ -2921,6 +2922,169 @@ out:
     return ret;
 }
 
+struct VFIODeviceFind {
+    PCIDevice *pdev;
+    bool found;
+};
+
+static void find_devices(PCIBus *bus, void *opaque)
+{
+    struct VFIODeviceFind *find = opaque;
+    int i;
+
+    if (find->found) {
+        return;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(bus->devices); i++) {
+        if (!bus->devices[i]) {
+            continue;
+        }
+
+        if (bus->devices[i] == find->pdev) {
+            find->found = true;
+            break;
+        }
+    }
+}
+
+static void vfio_check_device_reset(PCIBus *bus, void *opaque)
+{
+    int i;
+    PCIDevice *dev;
+    VFIOPCIDevice *vdev;
+    struct VFIODeviceFind *find = opaque;
+
+    if (find->found) {
+        return;
+    }
+
+    for (i = 0; i < ARRAY_SIZE(bus->devices); i++) {
+        if (!bus->devices[i]) {
+            continue;
+        }
+        dev = bus->devices[i];
+        if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
+            continue;
+        }
+        vdev = DO_UPCAST(VFIOPCIDevice, pdev, dev);
+        if (!(vdev->features & VFIO_FEATURE_ENABLE_AER) &&
+            !vdev->vbasedev.reset_works &&
+            !vdev->has_flr &&
+            !vdev->has_pm_reset) {
+            find->pdev = dev;
+            find->found = true;
+            break;
+        }
+    }
+}
+
+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;
+    int ret, i;
+    struct VFIODeviceFind find;
+
+    ret = vfio_get_hot_reset_info(vdev, &info);
+    if (ret) {
+        goto out;
+    }
+
+    /* 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;
+
+        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) {
+            ret = -1;
+            goto out;
+        }
+
+        /* Ensure affected devices for reset under the same 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)) {
+                find.pdev = &tmp->pdev;
+                find.found = false;
+
+                pci_for_each_bus(bus, find_devices, &find);
+                if (!find.found) {
+                    ret = -1;
+                    goto out;
+                }
+                break;
+            }
+        }
+    }
+
+    /*
+     * Check the all vfio pci devices on or below the target bus
+     * have a reset mechanism at least.
+     */
+    find.pdev = NULL;
+    find.found = false;
+    pci_for_each_bus(bus, vfio_check_device_reset, &find);
+    if (find.found) {
+        ret = -1;
+        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) {
+            vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+            if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
+                vfio_check_host_bus_reset(vdev)) {
+                error_report("vfio: Cannot enable AER for device %s, "
+                             "which does not support host bus reset.",
+                              vdev->vbasedev.name);
+                 return -1;
+            }
+        }
+    }
+
+    return 0;
+}
+
 static int vfio_setup_aer(VFIOPCIDevice *vdev, uint8_t cap_ver,
                           int pos, uint16_t size)
 {
@@ -2963,6 +3127,11 @@ static int vfio_setup_aer(VFIOPCIDevice *vdev, uint8_t 
cap_ver,
         goto error;
     }
 
+    /* Make sure this devices does conflict the existing aer topology */
+    if (vfio_check_devices_host_bus_reset()) {
+        goto error;
+    }
+
     errcap = vfio_pci_read_config(pdev, pdev->exp.aer_cap + PCI_ERR_CAP, 4);
     /*
      * The ability to record multiple headers is depending on
-- 
1.9.3