[PATCH 09/12] iommu/vt-d: Check device list of domain in domain free path

Lu Baolu
2022-05-27T06:34:28Z

When the IOMMU domain is about to be freed, it should not be set on any
device. Instead of silently dealing with some bug cases, it's better to
trigger a warning to report and fix any potential bugs at the first time.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.c | 17 ++---------------
1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2e195a639502..6f3119c68cd2 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -294,7 +294,6 @@ static LIST_HEAD(dmar_satc_units);
/* bitmap for indexing intel_iommus */
static int g_num_of_iommus;

-static void domain_remove_dev_info(struct dmar_domain *domain);
static void dmar_remove_one_dev_info(struct device *dev);
static void __dmar_remove_one_dev_info(struct device_domain_info *info);

@@ -1835,9 +1834,8 @@ static inline int guestwidth_to_adjustwidth(int gaw)

static void domain_exit(struct dmar_domain *domain)
{
-
- /* Remove associated devices and clear attached or cached domains */
- domain_remove_dev_info(domain);
+ if (WARN_ON(!list_empty(&domain->devices)))
+ return;

if (domain->pgd) {
LIST_HEAD(freelist);
@@ -2328,17 +2326,6 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8
__iommu_flush_dev_iotlb(info, 0, MAX_AGAW_PFN_WIDTH);
}

-static void domain_remove_dev_info(struct dmar_domain *domain)
-{
- struct device_domain_info *info, *tmp;
- unsigned long flags;
-
- spin_lock_irqsave(&device_domain_lock, flags);
- list_for_each_entry_safe(info, tmp, &domain->devices, link)
- __dmar_remove_one_dev_info(info);
- spin_unlock_irqrestore(&device_domain_lock, flags);
-}
-
static int domain_setup_first_level(struct intel_iommu *iommu,
struct dmar_domain *domain,
struct device *dev,
--
2.25.1