vfio/iommufd: Enable pci hot reset through iommufd cdev interface

Implement the newly introduced pci_hot_reset callback named
iommufd_cdev_pci_hot_reset to do iommufd specific check and
reset operation.

Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Cédric Le Goater <clg@redhat.com>

hw/vfio/iommufd.c

@@ -24,6 +24,7 @@
 #include "sysemu/reset.h"
 #include "qemu/cutils.h"
 #include "qemu/chardev_open.h"
+#include "pci.h"
 
 static int iommufd_cdev_map(VFIOContainerBase *bcontainer, hwaddr iova,
                             ram_addr_t size, void *vaddr, bool readonly)
@@ -468,9 +469,158 @@ static void iommufd_cdev_detach(VFIODevice *vbasedev)
     close(vbasedev->fd);
 }
 
+static VFIODevice *iommufd_cdev_pci_find_by_devid(__u32 devid)
+{
+    VFIODevice *vbasedev_iter;
+
+    QLIST_FOREACH(vbasedev_iter, &vfio_device_list, global_next) {
+        if (vbasedev_iter->bcontainer->ops != &vfio_iommufd_ops) {
+            continue;
+        }
+        if (devid == vbasedev_iter->devid) {
+            return vbasedev_iter;
+        }
+    }
+    return NULL;
+}
+
+static VFIOPCIDevice *
+iommufd_cdev_dep_get_realized_vpdev(struct vfio_pci_dependent_device *dep_dev,
+                                    VFIODevice *reset_dev)
+{
+    VFIODevice *vbasedev_tmp;
+
+    if (dep_dev->devid == reset_dev->devid ||
+        dep_dev->devid == VFIO_PCI_DEVID_OWNED) {
+        return NULL;
+    }
+
+    vbasedev_tmp = iommufd_cdev_pci_find_by_devid(dep_dev->devid);
+    if (!vbasedev_tmp || !vbasedev_tmp->dev->realized ||
+        vbasedev_tmp->type != VFIO_DEVICE_TYPE_PCI) {
+        return NULL;
+    }
+
+    return container_of(vbasedev_tmp, VFIOPCIDevice, vbasedev);
+}
+
+static int iommufd_cdev_pci_hot_reset(VFIODevice *vbasedev, bool single)
+{
+    VFIOPCIDevice *vdev = container_of(vbasedev, VFIOPCIDevice, vbasedev);
+    struct vfio_pci_hot_reset_info *info = NULL;
+    struct vfio_pci_dependent_device *devices;
+    struct vfio_pci_hot_reset *reset;
+    int ret, i;
+    bool multi = false;
+
+    trace_vfio_pci_hot_reset(vdev->vbasedev.name, single ? "one" : "multi");
+
+    if (!single) {
+        vfio_pci_pre_reset(vdev);
+    }
+    vdev->vbasedev.needs_reset = false;
+
+    ret = vfio_pci_get_pci_hot_reset_info(vdev, &info);
+
+    if (ret) {
+        goto out_single;
+    }
+
+    assert(info->flags & VFIO_PCI_HOT_RESET_FLAG_DEV_ID);
+
+    devices = &info->devices[0];
+
+    if (!(info->flags & VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED)) {
+        if (!vdev->has_pm_reset) {
+            for (i = 0; i < info->count; i++) {
+                if (devices[i].devid == VFIO_PCI_DEVID_NOT_OWNED) {
+                    error_report("vfio: Cannot reset device %s, "
+                                 "depends on device %04x:%02x:%02x.%x "
+                                 "which is not owned.",
+                                 vdev->vbasedev.name, devices[i].segment,
+                                 devices[i].bus, PCI_SLOT(devices[i].devfn),
+                                 PCI_FUNC(devices[i].devfn));
+                }
+            }
+        }
+        ret = -EPERM;
+        goto out_single;
+    }
+
+    trace_vfio_pci_hot_reset_has_dep_devices(vdev->vbasedev.name);
+
+    for (i = 0; i < info->count; i++) {
+        VFIOPCIDevice *tmp;
+
+        trace_iommufd_cdev_pci_hot_reset_dep_devices(devices[i].segment,
+                                                     devices[i].bus,
+                                                     PCI_SLOT(devices[i].devfn),
+                                                     PCI_FUNC(devices[i].devfn),
+                                                     devices[i].devid);
+
+        /*
+         * If a VFIO cdev device is resettable, all the dependent devices
+         * are either bound to same iommufd or within same iommu_groups as
+         * one of the iommufd bound devices.
+         */
+        assert(devices[i].devid != VFIO_PCI_DEVID_NOT_OWNED);
+
+        tmp = iommufd_cdev_dep_get_realized_vpdev(&devices[i], &vdev->vbasedev);
+        if (!tmp) {
+            continue;
+        }
+
+        if (single) {
+            ret = -EINVAL;
+            goto out_single;
+        }
+        vfio_pci_pre_reset(tmp);
+        tmp->vbasedev.needs_reset = false;
+        multi = true;
+    }
+
+    if (!single && !multi) {
+        ret = -EINVAL;
+        goto out_single;
+    }
+
+    /* Use zero length array for hot reset with iommufd backend */
+    reset = g_malloc0(sizeof(*reset));
+    reset->argsz = sizeof(*reset);
+
+     /* Bus reset! */
+    ret = ioctl(vdev->vbasedev.fd, VFIO_DEVICE_PCI_HOT_RESET, reset);
+    g_free(reset);
+    if (ret) {
+        ret = -errno;
+    }
+
+    trace_vfio_pci_hot_reset_result(vdev->vbasedev.name,
+                                    ret ? strerror(errno) : "Success");
+
+    /* Re-enable INTx on affected devices */
+    for (i = 0; i < info->count; i++) {
+        VFIOPCIDevice *tmp;
+
+        tmp = iommufd_cdev_dep_get_realized_vpdev(&devices[i], &vdev->vbasedev);
+        if (!tmp) {
+            continue;
+        }
+        vfio_pci_post_reset(tmp);
+    }
+out_single:
+    if (!single) {
+        vfio_pci_post_reset(vdev);
+    }
+    g_free(info);
+
+    return ret;
+}
+
 const VFIOIOMMUOps vfio_iommufd_ops = {
     .dma_map = iommufd_cdev_map,
     .dma_unmap = iommufd_cdev_unmap,
     .attach_device = iommufd_cdev_attach,
     .detach_device = iommufd_cdev_detach,
+    .pci_hot_reset = iommufd_cdev_pci_hot_reset,
 };

hw/vfio/trace-events

@@ -174,3 +174,4 @@ iommufd_cdev_detach_ioas_hwpt(int iommufd, const char *name) " [iommufd=%d] Succ
 iommufd_cdev_fail_attach_existing_container(const char *msg) " %s"
 iommufd_cdev_alloc_ioas(int iommufd, int ioas_id) " [iommufd=%d] new IOMMUFD container with ioasid=%d"
 iommufd_cdev_device_info(char *name, int devfd, int num_irqs, int num_regions, int flags) " %s (%d) num_irqs=%d num_regions=%d flags=%d"
+iommufd_cdev_pci_hot_reset_dep_devices(int domain, int bus, int slot, int function, int dev_id) "\t%04x:%02x:%02x.%x devid %d"