[Qemu-devel] [RFC v7 11/11] vfio: add 'aer' property to expose aercap

[Chen Fan]

add 'aer' property to let user able to decide whether expose
the aer capability. by default we should disable aer feature,
because it needs configuration restrictions.

Signed-off-by: Chen Fan <address@hidden>
---
 hw/i386/pc_q35.c    |  4 +++
 hw/vfio/pci.c       | 84 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/compat.h |  8 +++++
 3 files changed, 96 insertions(+)

diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c
index e67f2de..94a3a1c 100644
--- a/hw/i386/pc_q35.c
+++ b/hw/i386/pc_q35.c
@@ -439,6 +439,10 @@ static QEMUMachine pc_q35_machine_v2_3 = {
     PC_Q35_2_3_MACHINE_OPTIONS,
     .name = "pc-q35-2.3",
     .init = pc_q35_init_2_3,
+    .compat_props = (GlobalProperty[]) {
+        HW_COMPAT_2_3,
+        { /* end of list */ }
+    },
 };
 
 #define PC_Q35_2_2_MACHINE_OPTIONS PC_Q35_2_3_MACHINE_OPTIONS
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index f2fc5d6..b4b9495 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -42,6 +42,7 @@
 #include "trace.h"
 #include "hw/vfio/vfio.h"
 #include "hw/vfio/vfio-common.h"
+#include "hw/pci/pci_bridge.h"
 
 struct VFIOPCIDevice;
 
@@ -161,6 +162,8 @@ typedef struct VFIOPCIDevice {
 #define VFIO_FEATURE_ENABLE_VGA (1 << VFIO_FEATURE_ENABLE_VGA_BIT)
 #define VFIO_FEATURE_ENABLE_REQ_BIT 1
 #define VFIO_FEATURE_ENABLE_REQ (1 << VFIO_FEATURE_ENABLE_REQ_BIT)
+#define VFIO_FEATURE_ENABLE_AER_BIT 2
+#define VFIO_FEATURE_ENABLE_AER (1 << VFIO_FEATURE_ENABLE_AER_BIT)
     int32_t bootindex;
     uint8_t pm_cap;
     bool has_vga;
@@ -2821,10 +2824,31 @@ static int vfio_add_std_cap(VFIOPCIDevice *vdev, 
uint8_t pos)
 static int vfio_setup_aer(VFIOPCIDevice *vdev, int pos, uint16_t size)
 {
     PCIDevice *pdev = &vdev->pdev;
+    PCIDevice *dev_iter;
     uint8_t *exp_cap = pdev->config + pdev->exp.exp_cap;
     uint32_t severity, errcap;
+    uint8_t type;
     int ret;
 
+    if (!(vdev->features & VFIO_FEATURE_ENABLE_AER)) {
+        return 0;
+    }
+
+    dev_iter = pci_bridge_get_device(pdev->bus);
+    if (!dev_iter) {
+        goto error;
+    }
+
+    while (dev_iter) {
+        type = pcie_cap_get_type(dev_iter);
+        if ((type != PCI_EXP_TYPE_ROOT_PORT &&
+             type != PCI_EXP_TYPE_UPSTREAM &&
+             type != PCI_EXP_TYPE_DOWNSTREAM)) {
+            goto error;
+        }
+        dev_iter = pci_bridge_get_device(dev_iter->bus);
+    }
+
     errcap = vfio_pci_read_config(pdev, pdev->exp.aer_cap + PCI_ERR_CAP, 4);
     /*
      * The ability to record multiple headers is depending on
@@ -2850,6 +2874,11 @@ static int vfio_setup_aer(VFIOPCIDevice *vdev, int pos, 
uint16_t size)
     pci_long_test_and_clear_mask(exp_cap + PCI_ERR_UNCOR_SEVER, ~severity);
 
     return 0;
+
+error:
+    error_report("vfio: Unable to enable AER for device %s, parent bus "
+                 "do not support signal AER", vdev->vbasedev.name);
+    return -1;
 }
 
 static int vfio_add_ext_cap(VFIOPCIDevice *vdev, const uint8_t *config)
@@ -3733,9 +3762,52 @@ static void vfio_check_host_bus_reset(VFIODevice 
*vbasedev)
     vdev->has_bus_reset = true;
 
 out:
+    if ((vdev->features & VFIO_FEATURE_ENABLE_AER) &&
+        !vdev->has_bus_reset) {
+        error_report("vfio: Cannot enable AER for device %s,"
+                     "which is not support host bus reset.",
+                     vdev->vbasedev.name);
+        exit(1);
+    }
     g_free(info);
 }
 
+static int vfio_pci_validate_aer_devices(DeviceState *dev,
+                                         void *opaque)
+{
+    VFIOPCIDevice *vdev;
+
+    if (!object_dynamic_cast(OBJECT(dev), "vfio-pci")) {
+        return 0;
+    }
+
+    vdev = DO_UPCAST(VFIOPCIDevice, pdev, PCI_DEVICE(dev));
+    if (!vdev->has_bus_reset) {
+        error_report("vfio: device %s is not support host bus reset,"
+                     "but on the same bus has vfio device enable AER.",
+                     vdev->vbasedev.name);
+        exit(1);
+    }
+    return 0;
+}
+
+static void vfio_check_virtual_bus_reset(VFIODevice *vbasedev)
+{
+    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+
+    if (!(vdev->features & VFIO_FEATURE_ENABLE_AER)) {
+        return;
+    }
+
+    /*
+     * Verify that we have all the vfio devices support host bus reset
+     * on the bus
+     */
+    qbus_walk_children(BUS(vdev->pdev.bus), NULL, NULL,
+                       vfio_pci_validate_aer_devices,
+                       NULL, NULL);
+}
+
 static void vfio_pci_machine_done_notify(Notifier *notifier, void *unused)
 {
     VFIOGroup *group;
@@ -3746,6 +3818,16 @@ static void vfio_pci_machine_done_notify(Notifier 
*notifier, void *unused)
              vfio_check_host_bus_reset(vbasedev);
          }
     }
+
+    /*
+     * All devices need support host bus reset on each virtual bus
+     * if one device enable AER.
+     */
+    QLIST_FOREACH(group, &vfio_group_list, next) {
+         QLIST_FOREACH(vbasedev, &group->device_list, next) {
+             vfio_check_virtual_bus_reset(vbasedev);
+         }
+    }
 }
 
 static Notifier machine_notifier = {
@@ -4004,6 +4086,8 @@ static Property vfio_pci_dev_properties[] = {
                     VFIO_FEATURE_ENABLE_VGA_BIT, false),
     DEFINE_PROP_BIT("x-req", VFIOPCIDevice, features,
                     VFIO_FEATURE_ENABLE_REQ_BIT, true),
+    DEFINE_PROP_BIT("aer", VFIOPCIDevice, features,
+                    VFIO_FEATURE_ENABLE_AER_BIT, false),
     DEFINE_PROP_INT32("bootindex", VFIOPCIDevice, bootindex, -1),
     DEFINE_PROP_BOOL("x-mmap", VFIOPCIDevice, vbasedev.allow_mmap, true),
     /*
diff --git a/include/hw/compat.h b/include/hw/compat.h
index 313682a..f722919 100644
--- a/include/hw/compat.h
+++ b/include/hw/compat.h
@@ -1,7 +1,15 @@
 #ifndef HW_COMPAT_H
 #define HW_COMPAT_H
 
+#define HW_COMPAT_2_3 \
+        {\
+            .driver   = "vfio-pci",\
+            .property = "x-aer",\
+            .value    = "off",\
+        }
+
 #define HW_COMPAT_2_1 \
+        HW_COMPAT_2_3, \
         {\
             .driver   = "intel-hda",\
             .property = "old_msi_addr",\
-- 
1.9.3