iommu: Return right value in iommu_sva_bind_device()

mainline inclusion
from mainline-v6.10-rc3
commit 89e8a2366e3bce584b6c01549d5019c5cda1205e
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACSKO
CVE: CVE-2024-40945

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=89e8a2366e3bce584b6c01549d5019c5cda1205e



--------------------------------

iommu_sva_bind_device() should return either a sva bond handle or an
ERR_PTR value in error cases. Existing drivers (idxd and uacce) only
check the return value with IS_ERR(). This could potentially lead to
a kernel NULL pointer dereference issue if the function returns NULL
instead of an error pointer.

In reality, this doesn't cause any problems because iommu_sva_bind_device()
only returns NULL when the kernel is not configured with CONFIG_IOMMU_SVA.
In this case, iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) will
return an error, and the device drivers won't call iommu_sva_bind_device()
at all.

Fixes: 26b25a2b ("iommu: Bind process address spaces to devices")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20240528042528.71396-1-baolu.lu@linux.intel.com


Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Cheng Yu <serein.chengyu@huawei.com>