Merge tag 'pull-vfio-20231219' of https://github.com/legoater/qemu into staging

vfio queue:

* Introduce an IOMMU interface backend for VFIO devices
* Convert IOMMU type1 and sPAPR IOMMU to respective backends
* Introduce a new IOMMUFD backend for ARM, x86_64 and s390x platforms

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* tag 'pull-vfio-20231219' of https://github.com/legoater/qemu: (47 commits)
  hw/ppc/Kconfig: Imply VFIO_PCI
  docs/devel: Add VFIO iommufd backend documentation
  vfio: Introduce a helper function to initialize VFIODevice
  vfio/ccw: Move VFIODevice initializations in vfio_ccw_instance_init
  vfio/ap: Move VFIODevice initializations in vfio_ap_instance_init
  vfio/platform: Move VFIODevice initializations in vfio_platform_instance_init
  vfio/pci: Move VFIODevice initializations in vfio_instance_init
  hw/i386: Activate IOMMUFD for q35 machines
  kconfig: Activate IOMMUFD for s390x machines
  hw/arm: Activate IOMMUFD for virt machines
  vfio: Make VFIOContainerBase poiner parameter const in VFIOIOMMUOps callbacks
  vfio/ccw: Make vfio cdev pre-openable by passing a file handle
  vfio/ccw: Allow the selection of a given iommu backend
  vfio/ap: Make vfio cdev pre-openable by passing a file handle
  vfio/ap: Allow the selection of a given iommu backend
  vfio/platform: Make vfio cdev pre-openable by passing a file handle
  vfio/platform: Allow the selection of a given iommu backend
  vfio/pci: Make vfio cdev pre-openable by passing a file handle
  vfio/pci: Allow the selection of a given iommu backend
  vfio/iommufd: Enable pci hot reset through iommufd cdev interface
  ...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 81 insertions, 0 deletions

diff --git a/util/chardev_open.c b/util/chardev_open.c
new file mode 100644
index 0000000000..f776429788
--- /dev/null
+++ b/util/chardev_open.c
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2019, Mellanox Technologies. All rights reserved.
+ * Copyright (C) 2023 Intel Corporation.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *      Redistribution and use in source and binary forms, with or
+ *      without modification, are permitted provided that the following
+ *      conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors: Yi Liu <yi.l.liu@intel.com>
+ *
+ * Copied from
+ * https://github.com/linux-rdma/rdma-core/blob/master/util/open_cdev.c
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/chardev_open.h"
+
+static int open_cdev_internal(const char *path, dev_t cdev)
+{
+    struct stat st;
+    int fd;
+
+    fd = qemu_open_old(path, O_RDWR);
+    if (fd == -1) {
+        return -1;
+    }
+    if (fstat(fd, &st) || !S_ISCHR(st.st_mode) ||
+        (cdev != 0 && st.st_rdev != cdev)) {
+        close(fd);
+        return -1;
+    }
+    return fd;
+}
+
+static int open_cdev_robust(dev_t cdev)
+{
+    g_autofree char *devpath = NULL;
+
+    /*
+     * This assumes that udev is being used and is creating the /dev/char/
+     * symlinks.
+     */
+    devpath = g_strdup_printf("/dev/char/%u:%u", major(cdev), minor(cdev));
+    return open_cdev_internal(devpath, cdev);
+}
+
+int open_cdev(const char *devpath, dev_t cdev)
+{
+    int fd;
+
+    fd = open_cdev_internal(devpath, cdev);
+    if (fd == -1 && cdev != 0) {
+        return open_cdev_robust(cdev);
+    }
+    return fd;
+}