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

Christoph Hellwig
2021-07-23T07:47:54Z

On Tue, Jul 20, 2021 at 02:42:54PM -0300, Jason Gunthorpe wrote:
> 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>