Merge tag 'vfio-v6.6-rc1' of https://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - VFIO direct character device (cdev) interface support. This extracts
   the vfio device fd from the container and group model, and is
   intended to be the native uAPI for use with IOMMUFD (Yi Liu)

 - Enhancements to the PCI hot reset interface in support of cdev usage
   (Yi Liu)

 - Fix a potential race between registering and unregistering vfio files
   in the kvm-vfio interface and extend use of a lock to avoid extra
   drop and acquires (Dmitry Torokhov)

 - A new vfio-pci variant driver for the AMD/Pensando Distributed
   Services Card (PDS) Ethernet device, supporting live migration (Brett
   Creeley)

 - Cleanups to remove redundant owner setup in cdx and fsl bus drivers,
   and simplify driver init/exit in fsl code (Li Zetao)

 - Fix uninitialized hole in data structure and pad capability
   structures for alignment (Stefan Hajnoczi)

* tag 'vfio-v6.6-rc1' of https://github.com/awilliam/linux-vfio: (53 commits)
  vfio/pds: Send type for SUSPEND_STATUS command
  vfio/pds: fix return value in pds_vfio_get_lm_file()
  pds_core: Fix function header descriptions
  vfio: align capability structures
  vfio/type1: fix cap_migration information leak
  vfio/fsl-mc: Use module_fsl_mc_driver macro to simplify the code
  vfio/cdx: Remove redundant initialization owner in vfio_cdx_driver
  vfio/pds: Add Kconfig and documentation
  vfio/pds: Add support for firmware recovery
  vfio/pds: Add support for dirty page tracking
  vfio/pds: Add VFIO live migration support
  vfio/pds: register with the pds_core PF
  pds_core: Require callers of register/unregister to pass PF drvdata
  vfio/pds: Initial support for pds VFIO driver
  vfio: Commonize combine_ranges for use in other VFIO drivers
  kvm/vfio: avoid bouncing the mutex when adding and deleting groups
  kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add()
  docs: vfio: Add vfio device cdev description
  vfio: Compile vfio_group infrastructure optionally
  vfio: Move the IOMMU_CAP_CACHE_COHERENCY check in __vfio_register_dev()
  ...

1 files changed, 209 insertions, 0 deletions

diff --git a/drivers/vfio/pci/pds/pci_drv.c b/drivers/vfio/pci/pds/pci_drv.c
new file mode 100644
index 000000000000..ab4b5958e413
--- /dev/null
+++ b/drivers/vfio/pci/pds/pci_drv.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright(c) 2023 Advanced Micro Devices, Inc. */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/types.h>
+#include <linux/vfio.h>
+
+#include <linux/pds/pds_common.h>
+#include <linux/pds/pds_core_if.h>
+#include <linux/pds/pds_adminq.h>
+
+#include "vfio_dev.h"
+#include "pci_drv.h"
+#include "cmds.h"
+
+#define PDS_VFIO_DRV_DESCRIPTION	"AMD/Pensando VFIO Device Driver"
+#define PCI_VENDOR_ID_PENSANDO		0x1dd8
+
+static void pds_vfio_recovery(struct pds_vfio_pci_device *pds_vfio)
+{
+	bool deferred_reset_needed = false;
+
+	/*
+	 * Documentation states that the kernel migration driver must not
+	 * generate asynchronous device state transitions outside of
+	 * manipulation by the user or the VFIO_DEVICE_RESET ioctl.
+	 *
+	 * Since recovery is an asynchronous event received from the device,
+	 * initiate a deferred reset. Issue a deferred reset in the following
+	 * situations:
+	 *   1. Migration is in progress, which will cause the next step of
+	 *	the migration to fail.
+	 *   2. If the device is in a state that will be set to
+	 *	VFIO_DEVICE_STATE_RUNNING on the next action (i.e. VM is
+	 *	shutdown and device is in VFIO_DEVICE_STATE_STOP).
+	 */
+	mutex_lock(&pds_vfio->state_mutex);
+	if ((pds_vfio->state != VFIO_DEVICE_STATE_RUNNING &&
+	     pds_vfio->state != VFIO_DEVICE_STATE_ERROR) ||
+	    (pds_vfio->state == VFIO_DEVICE_STATE_RUNNING &&
+	     pds_vfio_dirty_is_enabled(pds_vfio)))
+		deferred_reset_needed = true;
+	mutex_unlock(&pds_vfio->state_mutex);
+
+	/*
+	 * On the next user initiated state transition, the device will
+	 * transition to the VFIO_DEVICE_STATE_ERROR. At this point it's the user's
+	 * responsibility to reset the device.
+	 *
+	 * If a VFIO_DEVICE_RESET is requested post recovery and before the next
+	 * state transition, then the deferred reset state will be set to
+	 * VFIO_DEVICE_STATE_RUNNING.
+	 */
+	if (deferred_reset_needed) {
+		spin_lock(&pds_vfio->reset_lock);
+		pds_vfio->deferred_reset = true;
+		pds_vfio->deferred_reset_state = VFIO_DEVICE_STATE_ERROR;
+		spin_unlock(&pds_vfio->reset_lock);
+	}
+}
+
+static int pds_vfio_pci_notify_handler(struct notifier_block *nb,
+				       unsigned long ecode, void *data)
+{
+	struct pds_vfio_pci_device *pds_vfio =
+		container_of(nb, struct pds_vfio_pci_device, nb);
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	union pds_core_notifyq_comp *event = data;
+
+	dev_dbg(dev, "%s: event code %lu\n", __func__, ecode);
+
+	/*
+	 * We don't need to do anything for RESET state==0 as there is no notify
+	 * or feedback mechanism available, and it is possible that we won't
+	 * even see a state==0 event since the pds_core recovery is pending.
+	 *
+	 * Any requests from VFIO while state==0 will fail, which will return
+	 * error and may cause migration to fail.
+	 */
+	if (ecode == PDS_EVENT_RESET) {
+		dev_info(dev, "%s: PDS_EVENT_RESET event received, state==%d\n",
+			 __func__, event->reset.state);
+		/*
+		 * pds_core device finished recovery and sent us the
+		 * notification (state == 1) to allow us to recover
+		 */
+		if (event->reset.state == 1)
+			pds_vfio_recovery(pds_vfio);
+	}
+
+	return 0;
+}
+
+static int
+pds_vfio_pci_register_event_handler(struct pds_vfio_pci_device *pds_vfio)
+{
+	struct device *dev = pds_vfio_to_dev(pds_vfio);
+	struct notifier_block *nb = &pds_vfio->nb;
+	int err;
+
+	if (!nb->notifier_call) {
+		nb->notifier_call = pds_vfio_pci_notify_handler;
+		err = pdsc_register_notify(nb);
+		if (err) {
+			nb->notifier_call = NULL;
+			dev_err(dev,
+				"failed to register pds event handler: %pe\n",
+				ERR_PTR(err));
+			return -EINVAL;
+		}
+		dev_dbg(dev, "pds event handler registered\n");
+	}
+
+	return 0;
+}
+
+static void
+pds_vfio_pci_unregister_event_handler(struct pds_vfio_pci_device *pds_vfio)
+{
+	if (pds_vfio->nb.notifier_call) {
+		pdsc_unregister_notify(&pds_vfio->nb);
+		pds_vfio->nb.notifier_call = NULL;
+	}
+}
+
+static int pds_vfio_pci_probe(struct pci_dev *pdev,
+			      const struct pci_device_id *id)
+{
+	struct pds_vfio_pci_device *pds_vfio;
+	int err;
+
+	pds_vfio = vfio_alloc_device(pds_vfio_pci_device, vfio_coredev.vdev,
+				     &pdev->dev, pds_vfio_ops_info());
+	if (IS_ERR(pds_vfio))
+		return PTR_ERR(pds_vfio);
+
+	dev_set_drvdata(&pdev->dev, &pds_vfio->vfio_coredev);
+
+	err = vfio_pci_core_register_device(&pds_vfio->vfio_coredev);
+	if (err)
+		goto out_put_vdev;
+
+	err = pds_vfio_register_client_cmd(pds_vfio);
+	if (err) {
+		dev_err(&pdev->dev, "failed to register as client: %pe\n",
+			ERR_PTR(err));
+		goto out_unregister_coredev;
+	}
+
+	err = pds_vfio_pci_register_event_handler(pds_vfio);
+	if (err)
+		goto out_unregister_client;
+
+	return 0;
+
+out_unregister_client:
+	pds_vfio_unregister_client_cmd(pds_vfio);
+out_unregister_coredev:
+	vfio_pci_core_unregister_device(&pds_vfio->vfio_coredev);
+out_put_vdev:
+	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
+	return err;
+}
+
+static void pds_vfio_pci_remove(struct pci_dev *pdev)
+{
+	struct pds_vfio_pci_device *pds_vfio = pds_vfio_pci_drvdata(pdev);
+
+	pds_vfio_pci_unregister_event_handler(pds_vfio);
+	pds_vfio_unregister_client_cmd(pds_vfio);
+	vfio_pci_core_unregister_device(&pds_vfio->vfio_coredev);
+	vfio_put_device(&pds_vfio->vfio_coredev.vdev);
+}
+
+static const struct pci_device_id pds_vfio_pci_table[] = {
+	{ PCI_DRIVER_OVERRIDE_DEVICE_VFIO(PCI_VENDOR_ID_PENSANDO, 0x1003) }, /* Ethernet VF */
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, pds_vfio_pci_table);
+
+static void pds_vfio_pci_aer_reset_done(struct pci_dev *pdev)
+{
+	struct pds_vfio_pci_device *pds_vfio = pds_vfio_pci_drvdata(pdev);
+
+	pds_vfio_reset(pds_vfio);
+}
+
+static const struct pci_error_handlers pds_vfio_pci_err_handlers = {
+	.reset_done = pds_vfio_pci_aer_reset_done,
+	.error_detected = vfio_pci_core_aer_err_detected,
+};
+
+static struct pci_driver pds_vfio_pci_driver = {
+	.name = KBUILD_MODNAME,
+	.id_table = pds_vfio_pci_table,
+	.probe = pds_vfio_pci_probe,
+	.remove = pds_vfio_pci_remove,
+	.err_handler = &pds_vfio_pci_err_handlers,
+	.driver_managed_dma = true,
+};
+
+module_pci_driver(pds_vfio_pci_driver);
+
+MODULE_DESCRIPTION(PDS_VFIO_DRV_DESCRIPTION);
+MODULE_AUTHOR("Brett Creeley <brett.creeley@amd.com>");
+MODULE_LICENSE("GPL");