linux-kernel - [RFC PATCH v2 21/32] iommu/vt-d: Clean the context entries of unpreserved devices

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: <20251202230303.1017519-22-skhawaja@google.com>
Date: Tue,  2 Dec 2025 23:02:51 +0000
From: Samiullah Khawaja <skhawaja@...gle.com>
To: David Woodhouse <dwmw2@...radead.org>, Lu Baolu <baolu.lu@...ux.intel.com>, 
	Joerg Roedel <joro@...tes.org>, Will Deacon <will@...nel.org>, 
	Pasha Tatashin <pasha.tatashin@...een.com>, Jason Gunthorpe <jgg@...pe.ca>, iommu@...ts.linux.dev
Cc: Samiullah Khawaja <skhawaja@...gle.com>, Robin Murphy <robin.murphy@....com>, 
	Pratyush Yadav <pratyush@...nel.org>, Kevin Tian <kevin.tian@...el.com>, 
	Alex Williamson <alex@...zbot.org>, linux-kernel@...r.kernel.org, 
	Saeed Mahameed <saeedm@...dia.com>, Adithya Jayachandran <ajayachandra@...dia.com>, 
	Parav Pandit <parav@...dia.com>, Leon Romanovsky <leonro@...dia.com>, William Tu <witu@...dia.com>, 
	Vipin Sharma <vipinsh@...gle.com>, dmatlack@...gle.com, YiFei Zhu <zhuyifei@...gle.com>, 
	Chris Li <chrisl@...nel.org>, praan@...gle.com
Subject: [RFC PATCH v2 21/32] iommu/vt-d: Clean the context entries of
 unpreserved devices

During normal shutdown the iommu translation is disabled. Since the root
table is preserved during live update, it needs to be cleaned up and the
context entries of the unpreserved devices need to be cleared.

Signed-off-by: Samiullah Khawaja <skhawaja@...gle.com>
---
 drivers/iommu/intel/iommu.c      | 33 ++++++++++++++++++++++++++++++--
 drivers/iommu/intel/iommu.h      |  1 +
 drivers/iommu/intel/liveupdate.c |  1 +
 3 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 3f69a073b2d8..84fef81ecf4d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -16,6 +16,7 @@
 #include <linux/crash_dump.h>
 #include <linux/dma-direct.h>
 #include <linux/dmi.h>
+#include <linux/iommu-lu.h>
 #include <linux/memory.h>
 #include <linux/pci.h>
 #include <linux/pci-ats.h>
@@ -52,6 +53,10 @@ static int rwbf_quirk;
 
 #define rwbf_required(iommu)	(rwbf_quirk || cap_rwbf((iommu)->cap))
 
+#ifdef CONFIG_LIVEUPDATE
+static void __clean_unpreserved_context_entries(struct intel_iommu *iommu);
+#endif
+
 /*
  * set to 1 to panic kernel if can't successfully enable VT-d
  * (used when kernel is launched w/ TXT)
@@ -2376,8 +2381,12 @@ void intel_iommu_shutdown(void)
 		/* Disable PMRs explicitly here. */
 		iommu_disable_protect_mem_regions(iommu);
 
-		/* Make sure the IOMMUs are switched off */
-		iommu_disable_translation(iommu);
+		if (iommu->iommu.outgoing_preserved_state) {
+			__clean_unpreserved_context_entries(iommu);
+		} else {
+			/* Make sure the IOMMUs are switched off */
+			iommu_disable_translation(iommu);
+		}
 	}
 }
 
@@ -2884,6 +2893,26 @@ static const struct iommu_dirty_ops intel_second_stage_dirty_ops = {
 	.set_dirty_tracking = intel_iommu_set_dirty_tracking,
 };
 
+static void __clean_unpreserved_context_entries(struct intel_iommu *iommu)
+{
+	struct device_domain_info *info;
+	struct pci_dev *pdev = NULL;
+
+	for_each_pci_dev(pdev) {
+		info = dev_iommu_priv_get(&pdev->dev);
+		if (!info)
+			continue;
+
+		if (info->iommu != iommu)
+			continue;
+
+		if (dev_iommu_preserved_state(&pdev->dev))
+			continue;
+
+		domain_context_clear(info);
+	}
+}
+
 static struct iommu_domain *
 intel_iommu_domain_alloc_second_stage(struct device *dev,
 				      struct intel_iommu *iommu, u32 flags)
diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index ea88c86030bb..1eb60ce1300f 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1283,6 +1283,7 @@ int intel_iommu_preserve_device(struct device *dev, struct device_ser *device_se
 void intel_iommu_unpreserve_device(struct device *dev, struct device_ser *device_ser);
 int intel_iommu_preserve(struct iommu_device *iommu, struct iommu_ser *iommu_ser);
 void intel_iommu_unpreserve(struct iommu_device *iommu, struct iommu_ser *iommu_ser);
+bool intel_iommu_liveupdate_clear_context_entries(struct intel_iommu *iommu);
 #endif
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
diff --git a/drivers/iommu/intel/liveupdate.c b/drivers/iommu/intel/liveupdate.c
index 491075802e4b..3f8c7f15bc36 100644
--- a/drivers/iommu/intel/liveupdate.c
+++ b/drivers/iommu/intel/liveupdate.c
@@ -9,6 +9,7 @@
 
 #include <linux/kexec_handover.h>
 #include <linux/liveupdate.h>
+#include <linux/iommu-lu.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 
-- 
2.52.0.158.g65b55ccf14-goog