linux-kernel - [PATCH 1/2] iommu: Consolidate pasid dma ownership check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230801063125.34995-2-baolu.lu@linux.intel.com>
Date:   Tue,  1 Aug 2023 14:31:24 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>,
        Robin Murphy <robin.murphy@....com>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Kevin Tian <kevin.tian@...el.com>,
        Jean-Philippe Brucker <jean-philippe@...aro.org>,
        Nicolin Chen <nicolinc@...dia.com>
Cc:     Yi Liu <yi.l.liu@...el.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        iommu@...ts.linux.dev, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 1/2] iommu: Consolidate pasid dma ownership check

When switching device DMA ownership, it is required that all the device's
pasid DMA be disabled. This is done by checking if the pasid array of the
group is empty. Consolidate all the open code into a single helper. No
intentional functionality change.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/iommu.c | 27 ++++++++++++++++++++-------
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 4352a149a935..1a8fb30341e6 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -3034,6 +3034,17 @@ static bool iommu_is_default_domain(struct iommu_group *group)
 	return false;
 }
 
+/*
+ * Assert no PASID DMA when claiming or releasing group's DMA ownership.
+ * The iommu_xxx_device_pasid() interfaces are only for device drivers
+ * that have claimed the DMA ownership. Otherwise, it's a driver bug.
+ */
+static void assert_pasid_dma_ownership(struct iommu_group *group)
+{
+	lockdep_assert_held(&group->mutex);
+	WARN_ON(!xa_empty(&group->pasid_array));
+}
+
 /**
  * iommu_device_use_default_domain() - Device driver wants to handle device
  *                                     DMA through the kernel DMA API.
@@ -3052,14 +3063,14 @@ int iommu_device_use_default_domain(struct device *dev)
 
 	mutex_lock(&group->mutex);
 	if (group->owner_cnt) {
-		if (group->owner || !iommu_is_default_domain(group) ||
-		    !xa_empty(&group->pasid_array)) {
+		if (group->owner || !iommu_is_default_domain(group)) {
 			ret = -EBUSY;
 			goto unlock_out;
 		}
 	}
 
 	group->owner_cnt++;
+	assert_pasid_dma_ownership(group);
 
 unlock_out:
 	mutex_unlock(&group->mutex);
@@ -3084,7 +3095,8 @@ void iommu_device_unuse_default_domain(struct device *dev)
 		return;
 
 	mutex_lock(&group->mutex);
-	if (!WARN_ON(!group->owner_cnt || !xa_empty(&group->pasid_array)))
+	assert_pasid_dma_ownership(group);
+	if (!WARN_ON(!group->owner_cnt))
 		group->owner_cnt--;
 
 	mutex_unlock(&group->mutex);
@@ -3118,8 +3130,7 @@ static int __iommu_take_dma_ownership(struct iommu_group *group, void *owner)
 {
 	int ret;
 
-	if ((group->domain && group->domain != group->default_domain) ||
-	    !xa_empty(&group->pasid_array))
+	if (group->domain && group->domain != group->default_domain)
 		return -EBUSY;
 
 	ret = __iommu_group_alloc_blocking_domain(group);
@@ -3129,8 +3140,10 @@ static int __iommu_take_dma_ownership(struct iommu_group *group, void *owner)
 	if (ret)
 		return ret;
 
+	assert_pasid_dma_ownership(group);
 	group->owner = owner;
 	group->owner_cnt++;
+
 	return 0;
 }
 
@@ -3206,10 +3219,10 @@ EXPORT_SYMBOL_GPL(iommu_device_claim_dma_owner);
 
 static void __iommu_release_dma_ownership(struct iommu_group *group)
 {
-	if (WARN_ON(!group->owner_cnt || !group->owner ||
-		    !xa_empty(&group->pasid_array)))
+	if (WARN_ON(!group->owner_cnt || !group->owner))
 		return;
 
+	assert_pasid_dma_ownership(group);
 	group->owner_cnt = 0;
 	group->owner = NULL;
 	__iommu_group_set_domain_nofail(group, group->default_domain);
-- 
2.34.1