[PATCH 2/3] iommu/vt-d: Fix oops due to out of scope access

[Lu Baolu <baolu.lu@linux.intel.com>]

From: Zhenzhong Duan <zhenzhong.duan@intel.com>

Below oops triggers when kill QEMU process:

  Oops: general protection fault, probably for non-canonical address 0x7fffffff844eaaa7: 0000 [#1] SMP NOPTI
  Call Trace:
   <TASK>
   do_raw_spin_lock+0xaa/0xc0
   _raw_spin_lock_irqsave+0x21/0x40
   domain_remove_dev_pasid+0x52/0x160
   intel_nested_set_dev_pasid+0x1b9/0x1e0
   __iommu_set_group_pasid+0x56/0x120
   pci_dev_reset_iommu_done+0xe3/0x180
   pcie_flr+0x65/0x160
   __pci_reset_function_locked+0x5b/0x120
   vfio_pci_core_close_device+0x63/0xe0 [vfio_pci_core]
   vfio_df_close+0x4f/0xa0
   vfio_df_unbind_iommufd+0x2d/0x60
   vfio_device_fops_release+0x3e/0x40
   __fput+0xe5/0x2c0
   task_work_run+0x58/0xa0
   do_exit+0x2c8/0x600
   do_group_exit+0x2f/0xa0
   get_signal+0x863/0x8c0
   arch_do_signal_or_restart+0x24/0x100
   exit_to_user_mode_loop+0x87/0x380
   do_syscall_64+0x2ff/0x11e0
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

The global static blocked domain is a dummy domain without corresponding
dmar_domain structure, accessing beyond iommu_domain structure triggers
oops easily. Fix it by return early in domain_remove_dev_pasid() like
identity domain.

Fixes: 7d0c9da6c150 ("iommu/vt-d: Add set_dev_pasid callback for dma domain")
Cc: stable@vger.kernel.org
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20260421031347.1408890-1-zhenzhong.duan@intel.com
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2a6b6813a78d..a4b123c33022 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -3530,8 +3530,8 @@ void domain_remove_dev_pasid(struct iommu_domain *domain,
 	if (!domain)
 		return;
 
-	/* Identity domain has no meta data for pasid. */
-	if (domain->type == IOMMU_DOMAIN_IDENTITY)
+	/* Identity domain and blocked domain have no meta data for pasid. */
+	if (domain->type == IOMMU_DOMAIN_IDENTITY || domain->type == IOMMU_DOMAIN_BLOCKED)
 		return;
 
 	dmar_domain = to_dmar_domain(domain);
-- 
2.43.0