Thread (43 messages) 43 messages, 4 authors, 2021-07-23

Re: [PATCH v2 08/14] vfio/pci: Move to the device set infrastructure

From: Christoph Hellwig <hch@lst.de>
Date: 2021-07-23 07:47:54
Also in: intel-gfx, linux-doc, linux-s390

On Tue, Jul 20, 2021 at 02:42:54PM -0300, Jason Gunthorpe wrote:
quoted hunk ↗ jump to hunk
From: Yishai Hadas <yishaih@nvidia.com>

PCI wants to have the usual open/close_device() logic with the slight
twist that the open/close_device() must be done under a singelton lock
shared by all of the vfio_devices that are in the PCI "reset group".

The reset group, and thus the device set, is determined by what devices
pci_reset_bus() touches, which is either the entire bus or only the slot.

Rely on the core code to do everything reflck was doing and delete reflck
entirely.

Signed-off-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/vfio/pci/vfio_pci.c         | 156 ++++++----------------------
 drivers/vfio/pci/vfio_pci_private.h |   7 --
 2 files changed, 31 insertions(+), 132 deletions(-)
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index fab3715d60d4ba..22774e447b5f4a 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -530,53 +530,40 @@ static void vfio_pci_vf_token_user_add(struct vfio_pci_device *vdev, int val)
 	vfio_device_put(&pf_vdev->vdev);
 }
 
-static void vfio_pci_release(struct vfio_device *core_vdev)
+static void vfio_pci_close_device(struct vfio_device *core_vdev)
 {
 	struct vfio_pci_device *vdev =
 		container_of(core_vdev, struct vfio_pci_device, vdev);
 
-	mutex_lock(&vdev->reflck->lock);
-
-	if (!(--vdev->refcnt)) {
-		vfio_pci_vf_token_user_add(vdev, -1);
-		vfio_spapr_pci_eeh_release(vdev->pdev);
-		vfio_pci_disable(vdev);
+	vfio_pci_vf_token_user_add(vdev, -1);
+	vfio_spapr_pci_eeh_release(vdev->pdev);
+	vfio_pci_disable(vdev);
 
-		mutex_lock(&vdev->igate);
-		if (vdev->err_trigger) {
-			eventfd_ctx_put(vdev->err_trigger);
-			vdev->err_trigger = NULL;
-		}
-		if (vdev->req_trigger) {
-			eventfd_ctx_put(vdev->req_trigger);
-			vdev->req_trigger = NULL;
-		}
-		mutex_unlock(&vdev->igate);
+	mutex_lock(&vdev->igate);
+	if (vdev->err_trigger) {
+		eventfd_ctx_put(vdev->err_trigger);
+		vdev->err_trigger = NULL;
 	}
-
-	mutex_unlock(&vdev->reflck->lock);
+	if (vdev->req_trigger) {
+		eventfd_ctx_put(vdev->req_trigger);
+		vdev->req_trigger = NULL;
+	}
+	mutex_unlock(&vdev->igate);
 }
 
-static int vfio_pci_open(struct vfio_device *core_vdev)
+static int vfio_pci_open_device(struct vfio_device *core_vdev)
 {
 	struct vfio_pci_device *vdev =
 		container_of(core_vdev, struct vfio_pci_device, vdev);
 	int ret = 0;
 
-	mutex_lock(&vdev->reflck->lock);
-
-	if (!vdev->refcnt) {
-		ret = vfio_pci_enable(vdev);
-		if (ret)
-			goto error;
+	ret = vfio_pci_enable(vdev);
+	if (ret)
+		return ret;
 
-		vfio_spapr_pci_eeh_open(vdev->pdev);
-		vfio_pci_vf_token_user_add(vdev, 1);
-	}
-	vdev->refcnt++;
-error:
-	mutex_unlock(&vdev->reflck->lock);
-	return ret;
+	vfio_spapr_pci_eeh_open(vdev->pdev);
+	vfio_pci_vf_token_user_add(vdev, 1);
+	return 0;
 }
 
 static int vfio_pci_get_irq_count(struct vfio_pci_device *vdev, int irq_type)
@@ -1870,8 +1857,8 @@ static int vfio_pci_match(struct vfio_device *core_vdev, char *buf)
 
 static const struct vfio_device_ops vfio_pci_ops = {
 	.name		= "vfio-pci",
-	.open		= vfio_pci_open,
-	.release	= vfio_pci_release,
+	.open_device	= vfio_pci_open_device,
+	.close_device	= vfio_pci_close_device,
 	.ioctl		= vfio_pci_ioctl,
 	.read		= vfio_pci_read,
 	.write		= vfio_pci_write,
@@ -1880,9 +1867,6 @@ static const struct vfio_device_ops vfio_pci_ops = {
 	.match		= vfio_pci_match,
 };
 
-static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev);
-static void vfio_pci_reflck_put(struct vfio_pci_reflck *reflck);
-
 static int vfio_pci_bus_notifier(struct notifier_block *nb,
 				 unsigned long action, void *data)
 {
@@ -2020,12 +2004,17 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	INIT_LIST_HEAD(&vdev->vma_list);
 	init_rwsem(&vdev->memory_lock);
 
-	ret = vfio_pci_reflck_attach(vdev);
+	if (pci_is_root_bus(pdev->bus))
+		ret = vfio_assign_device_set(&vdev->vdev, vdev);
+	else if (!pci_probe_reset_slot(pdev->slot))
+		ret = vfio_assign_device_set(&vdev->vdev, pdev->slot);
+	else
+		ret = vfio_assign_device_set(&vdev->vdev, pdev->bus);
Maybe invert this and add a comment:

	if (pci_is_root_bus(pdev->bus))
		ret = vfio_assign_device_set(&vdev->vdev, vdev);
	/*
	 * If there is no slot reset support for this device, the whole
	 * bus needs to be grouped together to support bus-wide resets.
	 */
	else if (pci_probe_reset_slot(pdev->slot) < 0)
		ret = vfio_assign_device_set(&vdev->vdev, pdev->bus);
	else
		ret = vfio_assign_device_set(&vdev->vdev, pdev->slot);

Otherwise looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>
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