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vfio/pci: Copy hot-reset device info to userspace in the devices loop

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This copies the vfio_pci_dependent_device to userspace during looping each
affected device for reporting vfio_pci_hot_reset_info. This avoids counting
the affected devices and allocating a potential large buffer to store the
vfio_pci_dependent_device of all the affected devices before copying them
to userspace.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Tested-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20230718105542.4138-10-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yi Liu 2023-07-18 03:55:41 -07:00 committed by Alex Williamson
parent 9062ff405b
commit b56b7aabcf
1 changed files with 33 additions and 60 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

93
drivers/vfio/pci/vfio_pci_core.c
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@ -777,19 +777,25 @@ static int vfio_pci_count_devs(struct pci_dev *pdev, void *data)
}
struct vfio_pci_fill_info {
int max;
int cur;
struct vfio_pci_dependent_device *devices;
struct vfio_pci_dependent_device __user *devices;
struct vfio_pci_dependent_device __user *devices_end;
struct vfio_device *vdev;
u32 count;
u32 flags;
};
static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
{
struct vfio_pci_dependent_device info = {
.segment = pci_domain_nr(pdev->bus),
.bus = pdev->bus->number,
.devfn = pdev->devfn,
};
struct vfio_pci_fill_info *fill = data;
if (fill->cur == fill->max)
return -EAGAIN; /* Something changed, try again */
fill->count++;
if (fill->devices >= fill->devices_end)
return 0;
if (fill->flags & VFIO_PCI_HOT_RESET_FLAG_DEV_ID) {
struct iommufd_ctx *iommufd = vfio_iommufd_device_ictx(fill->vdev);
@ -802,19 +808,19 @@ static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
*/
vdev = vfio_find_device_in_devset(dev_set, &pdev->dev);
if (!vdev) {
fill->devices[fill->cur].devid = VFIO_PCI_DEVID_NOT_OWNED;
info.devid = VFIO_PCI_DEVID_NOT_OWNED;
} else {
int id = vfio_iommufd_get_dev_id(vdev, iommufd);
if (id > 0)
fill->devices[fill->cur].devid = id;
info.devid = id;
else if (id == -ENOENT)
fill->devices[fill->cur].devid = VFIO_PCI_DEVID_OWNED;
info.devid = VFIO_PCI_DEVID_OWNED;
else
fill->devices[fill->cur].devid = VFIO_PCI_DEVID_NOT_OWNED;
info.devid = VFIO_PCI_DEVID_NOT_OWNED;
}
/* If devid is VFIO_PCI_DEVID_NOT_OWNED, clear owned flag. */
if (fill->devices[fill->cur].devid == VFIO_PCI_DEVID_NOT_OWNED)
if (info.devid == VFIO_PCI_DEVID_NOT_OWNED)
fill->flags &= ~VFIO_PCI_HOT_RESET_FLAG_DEV_ID_OWNED;
} else {
struct iommu_group *iommu_group;
@ -823,13 +829,13 @@ static int vfio_pci_fill_devs(struct pci_dev *pdev, void *data)
if (!iommu_group)
return -EPERM; /* Cannot reset non-isolated devices */
fill->devices[fill->cur].group_id = iommu_group_id(iommu_group);
info.group_id = iommu_group_id(iommu_group);
iommu_group_put(iommu_group);
}
fill->devices[fill->cur].segment = pci_domain_nr(pdev->bus);
fill->devices[fill->cur].bus = pdev->bus->number;
fill->devices[fill->cur].devfn = pdev->devfn;
fill->cur++;
if (copy_to_user(fill->devices, &info, sizeof(info)))
return -EFAULT;
fill->devices++;
return 0;
}
@ -1259,8 +1265,7 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
unsigned long minsz =
offsetofend(struct vfio_pci_hot_reset_info, count);
struct vfio_pci_hot_reset_info hdr;
struct vfio_pci_fill_info fill = { 0 };
struct vfio_pci_dependent_device *devices = NULL;
struct vfio_pci_fill_info fill = {};
bool slot = false;
int ret = 0;
@ -1278,29 +1283,9 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
else if (pci_probe_reset_bus(vdev->pdev->bus))
return -ENODEV;
/* How many devices are affected? */
ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_count_devs,
&fill.max, slot);
if (ret)
return ret;
WARN_ON(!fill.max); /* Should always be at least one */
/*
* If there's enough space, fill it now, otherwise return -ENOSPC and
* the number of devices affected.
*/
if (hdr.argsz < sizeof(hdr) + (fill.max * sizeof(*devices))) {
ret = -ENOSPC;
hdr.count = fill.max;
goto reset_info_exit;
}
devices = kcalloc(fill.max, sizeof(*devices), GFP_KERNEL);
if (!devices)
return -ENOMEM;
fill.devices = devices;
fill.devices = arg->devices;
fill.devices_end = arg->devices +
(hdr.argsz - sizeof(hdr)) / sizeof(arg->devices[0]);
fill.vdev = &vdev->vdev;
if (vfio_device_cdev_opened(&vdev->vdev))
@ -1311,29 +1296,17 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
ret = vfio_pci_for_each_slot_or_bus(vdev->pdev, vfio_pci_fill_devs,
&fill, slot);
mutex_unlock(&vdev->vdev.dev_set->lock);
if (ret)
return ret;
/*
* If a device was removed between counting and filling, we may come up
* short of fill.max. If a device was added, we'll have a return of
* -EAGAIN above.
*/
if (!ret) {
hdr.count = fill.cur;
hdr.flags = fill.flags;
}
reset_info_exit:
hdr.count = fill.count;
hdr.flags = fill.flags;
if (copy_to_user(arg, &hdr, minsz))
ret = -EFAULT;
return -EFAULT;
if (!ret) {
if (copy_to_user(&arg->devices, devices,
hdr.count * sizeof(*devices)))
ret = -EFAULT;
}
kfree(devices);
return ret;
if (fill.count > fill.devices - arg->devices)
return -ENOSPC;
return 0;
}
static int