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vfio/pci: Move to the device set infrastructure
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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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Link: https://lore.kernel.org/r/8-v4-9ea22c5e6afb+1adf-vfio_reflck_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
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Yishai Hadas authored and Alex Williamson committed Aug 11, 2021
1 parent ab7e5e3 commit 2cd8b14
Showing 2 changed files with 37 additions and 132 deletions.
162 changes: 37 additions & 125 deletions drivers/vfio/pci/vfio_pci.c
View file
Original file line number Diff line number Diff line change
@@ -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 +2004,23 @@ 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 {
/*
* If there is no slot reset support for this device, the whole
* bus needs to be grouped together to support bus-wide resets.
*/
ret = vfio_assign_device_set(&vdev->vdev, pdev->bus);
}

if (ret)
goto out_uninit;
ret = vfio_pci_vf_init(vdev);
if (ret)
goto out_reflck;
goto out_uninit;
ret = vfio_pci_vga_init(vdev);
if (ret)
goto out_vf;
@@ -2057,8 +2052,6 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
vfio_pci_set_power_state(vdev, PCI_D0);
out_vf:
vfio_pci_vf_uninit(vdev);
out_reflck:
vfio_pci_reflck_put(vdev->reflck);
out_uninit:
vfio_uninit_group_dev(&vdev->vdev);
kfree(vdev->pm_save);
@@ -2077,7 +2070,6 @@ static void vfio_pci_remove(struct pci_dev *pdev)
vfio_unregister_group_dev(&vdev->vdev);

vfio_pci_vf_uninit(vdev);
vfio_pci_reflck_put(vdev->reflck);
vfio_uninit_group_dev(&vdev->vdev);
vfio_pci_vga_uninit(vdev);

@@ -2153,86 +2145,6 @@ static struct pci_driver vfio_pci_driver = {
.err_handler = &vfio_err_handlers,
};

static DEFINE_MUTEX(reflck_lock);

static struct vfio_pci_reflck *vfio_pci_reflck_alloc(void)
{
struct vfio_pci_reflck *reflck;

reflck = kzalloc(sizeof(*reflck), GFP_KERNEL);
if (!reflck)
return ERR_PTR(-ENOMEM);

kref_init(&reflck->kref);
mutex_init(&reflck->lock);

return reflck;
}

static void vfio_pci_reflck_get(struct vfio_pci_reflck *reflck)
{
kref_get(&reflck->kref);
}

static int vfio_pci_reflck_find(struct pci_dev *pdev, void *data)
{
struct vfio_pci_reflck **preflck = data;
struct vfio_device *device;
struct vfio_pci_device *vdev;

device = vfio_device_get_from_dev(&pdev->dev);
if (!device)
return 0;

if (pci_dev_driver(pdev) != &vfio_pci_driver) {
vfio_device_put(device);
return 0;
}

vdev = container_of(device, struct vfio_pci_device, vdev);

if (vdev->reflck) {
vfio_pci_reflck_get(vdev->reflck);
*preflck = vdev->reflck;
vfio_device_put(device);
return 1;
}

vfio_device_put(device);
return 0;
}

static int vfio_pci_reflck_attach(struct vfio_pci_device *vdev)
{
bool slot = !pci_probe_reset_slot(vdev->pdev->slot);

mutex_lock(&reflck_lock);

if (pci_is_root_bus(vdev->pdev->bus) ||
vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_reflck_find,
&vdev->reflck, slot) <= 0)
vdev->reflck = vfio_pci_reflck_alloc();

mutex_unlock(&reflck_lock);

return PTR_ERR_OR_ZERO(vdev->reflck);
}

static void vfio_pci_reflck_release(struct kref *kref)
{
struct vfio_pci_reflck *reflck = container_of(kref,
struct vfio_pci_reflck,
kref);

kfree(reflck);
mutex_unlock(&reflck_lock);
}

static void vfio_pci_reflck_put(struct vfio_pci_reflck *reflck)
{
kref_put_mutex(&reflck->kref, vfio_pci_reflck_release, &reflck_lock);
}

static int vfio_pci_get_unused_devs(struct pci_dev *pdev, void *data)
{
struct vfio_devices *devs = data;
@@ -2254,7 +2166,7 @@ static int vfio_pci_get_unused_devs(struct pci_dev *pdev, void *data)
vdev = container_of(device, struct vfio_pci_device, vdev);

/* Fault if the device is not unused */
if (vdev->refcnt) {
if (device->open_count) {
vfio_device_put(device);
return -EBUSY;
}
@@ -2303,7 +2215,7 @@ static int vfio_pci_try_zap_and_vma_lock_cb(struct pci_dev *pdev, void *data)
* - At least one of the affected devices is marked dirty via
* needs_reset (such as by lack of FLR support)
* Then attempt to perform that bus or slot reset. Callers are required
* to hold vdev->reflck->lock, protecting the bus/slot reset group from
* to hold vdev->dev_set->lock, protecting the bus/slot reset group from
* concurrent opens. A vfio_device reference is acquired for each device
* to prevent unbinds during the reset operation.
*
7 changes: 0 additions & 7 deletions drivers/vfio/pci/vfio_pci_private.h
View file
Original file line number Diff line number Diff line change
@@ -83,11 +83,6 @@ struct vfio_pci_dummy_resource {
struct list_head res_next;
};

struct vfio_pci_reflck {
struct kref kref;
struct mutex lock;
};

struct vfio_pci_vf_token {
struct mutex lock;
uuid_t uuid;
@@ -130,8 +125,6 @@ struct vfio_pci_device {
bool needs_pm_restore;
struct pci_saved_state *pci_saved_state;
struct pci_saved_state *pm_save;
struct vfio_pci_reflck *reflck;
int refcnt;
int ioeventfds_nr;
struct eventfd_ctx *err_trigger;
struct eventfd_ctx *req_trigger;

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