[PATCH v3 00/11] iommu/vt-d: Optimize the use of locks

[PATCH v3 00/11] iommu/vt-d: Optimize the use of locks

[Lu Baolu]

Hi folks,

This series tries to optimize the uses of two locks in the Intel IOMMU
driver:

- The intel_iommu::lock is used to protect the IOMMU resources shared by
  devices. They include the IOMMU root and context tables, the pasid
  tables and the domain IDs.
- The global device_domain_lock is used to protect the global and the
  per-domain device tracking lists.

The optimization includes:

- Remove the unnecessary global device tracking list;
- Remove unnecessary locking;
- Reduce the scope of the lock as much as possible, that is, use the
  lock only where necessary;
- The global lock is transformed into a local lock to improve the
  efficiency.

This series is also available on github:
https://github.com/LuBaolu/intel-iommu/commits/intel-iommu-lock-optimization-v3

Your comments and suggestions are very appreciated.

Best regards,
baolu

Change log:

v3:
 - Split reduction of lock ranges from changing irqsave.
   https://lore.kernel.org/linux-iommu/BN9PR11MB52760A3D7C6BF1AF9C9D34658CAA9@BN9PR11MB5276.namprd11.prod.outlook.com/
 - Fully initialize the dev_info before adding it to the list.
   https://lore.kernel.org/linux-iommu/BN9PR11MB52764D7CD86448C5E4EB46668CAA9@BN9PR11MB5276.namprd11.prod.outlook.com/
 - Various code and comments refinement.

v2:
 - https://lore.kernel.org/linux-iommu/20220614025137.1632762-1-baolu.lu@linux.intel.com/
 - Split the lock-free page walk issue into a new patch:
   https://lore.kernel.org/linux-iommu/20220609070811.902868-1-baolu.lu@linux.intel.com/
 - Drop the conversion from spinlock to mutex and make this series
   cleanup purpose only.
 - Address several comments received during v1 review.

v1:
 - https://lore.kernel.org/linux-iommu/20220527063019.3112905-1-baolu.lu@linux.intel.com/
 - Initial post.

Lu Baolu (11):
  iommu/vt-d: debugfs: Remove device_domain_lock usage
  iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()
  iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk()
  iommu/vt-d: Unnecessary spinlock for root table alloc and free
  iommu/vt-d: Replace spin_lock_irqsave() with spin_lock()
  iommu/vt-d: Acquiring lock in domain ID allocation helpers
  iommu/vt-d: Acquiring lock in pasid manipulation helpers
  iommu/vt-d: Check device list of domain in domain free path
  iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller
  iommu/vt-d: Use device_domain_lock accurately
  iommu/vt-d: Convert global spinlock into per domain lock

 drivers/iommu/intel/iommu.h   |   3 +-
 drivers/iommu/intel/pasid.h   |   1 +
 drivers/iommu/intel/debugfs.c |  49 ++++---
 drivers/iommu/intel/iommu.c   | 248 ++++++++++------------------------
 drivers/iommu/intel/pasid.c   | 103 +++++++-------
 drivers/iommu/intel/svm.c     |   5 +-
 6 files changed, 164 insertions(+), 245 deletions(-)

-- 
2.25.1

[PATCH v3 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage

[Lu Baolu]

The domain_translation_struct debugfs node is used to dump the DMAR page
tables for the PCI devices. It potentially races with setting domains to
devices. The existing code uses the global spinlock device_domain_lock to
avoid the races.

This removes the use of device_domain_lock outside of iommu.c by replacing
it with the group mutex lock. Using the group mutex lock is cleaner and
more compatible to following cleanups.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.h   |  1 -
 drivers/iommu/intel/debugfs.c | 43 +++++++++++++++++++++++++----------
 drivers/iommu/intel/iommu.c   |  2 +-
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 8285fcfa5fea..8deb745d8b36 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -480,7 +480,6 @@ enum {
 #define VTD_FLAG_SVM_CAPABLE		(1 << 2)
 
 extern int intel_iommu_sm;
-extern spinlock_t device_domain_lock;
 
 #define sm_supported(iommu)	(intel_iommu_sm && ecap_smts((iommu)->ecap))
 #define pasid_supported(iommu)	(sm_supported(iommu) &&			\
diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c
index d927ef10641b..6e1a3f88abc8 100644
--- a/drivers/iommu/intel/debugfs.c
+++ b/drivers/iommu/intel/debugfs.c
@@ -342,13 +342,13 @@ static void pgtable_walk_level(struct seq_file *m, struct dma_pte *pde,
 	}
 }
 
-static int show_device_domain_translation(struct device *dev, void *data)
+static int __show_device_domain_translation(struct device *dev, void *data)
 {
-	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	struct dmar_domain *domain = info->domain;
+	struct dmar_domain *domain;
 	struct seq_file *m = data;
 	u64 path[6] = { 0 };
 
+	domain = to_dmar_domain(iommu_get_domain_for_dev(dev));
 	if (!domain)
 		return 0;
 
@@ -359,20 +359,39 @@ static int show_device_domain_translation(struct device *dev, void *data)
 	pgtable_walk_level(m, domain->pgd, domain->agaw + 2, 0, path);
 	seq_putc(m, '\n');
 
-	return 0;
+	/* Don't iterate */
+	return 1;
 }
 
-static int domain_translation_struct_show(struct seq_file *m, void *unused)
+static int show_device_domain_translation(struct device *dev, void *data)
 {
-	unsigned long flags;
-	int ret;
+	struct iommu_group *group;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
-	ret = bus_for_each_dev(&pci_bus_type, NULL, m,
-			       show_device_domain_translation);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	group = iommu_group_get(dev);
+	if (group) {
+		/*
+		 * The group->mutex is held across the callback, which will
+		 * block calls to iommu_attach/detach_group/device. Hence,
+		 * the domain of the device will not change during traversal.
+		 *
+		 * All devices in an iommu group share a single domain, hence
+		 * we only dump the domain of the first device. Even though,
+		 * this code still possibly races with the iommu_unmap()
+		 * interface. This could be solved by RCU-freeing the page
+		 * table pages in the iommu_unmap() path.
+		 */
+		iommu_group_for_each_dev(group, data,
+					 __show_device_domain_translation);
+		iommu_group_put(group);
+	}
 
-	return ret;
+	return 0;
+}
+
+static int domain_translation_struct_show(struct seq_file *m, void *unused)
+{
+	return bus_for_each_dev(&pci_bus_type, NULL, m,
+				show_device_domain_translation);
 }
 DEFINE_SHOW_ATTRIBUTE(domain_translation_struct);
 
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 10bda4bec8fe..3b6571681bdd 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -314,7 +314,7 @@ static int iommu_skip_te_disable;
 #define IDENTMAP_GFX		2
 #define IDENTMAP_AZALIA		4
 
-DEFINE_SPINLOCK(device_domain_lock);
+static DEFINE_SPINLOCK(device_domain_lock);
 static LIST_HEAD(device_domain_list);
 
 const struct iommu_ops intel_iommu_ops;
-- 
2.25.1

RE: [PATCH v3 01/11] iommu/vt-d: debugfs: Remove device_domain_lock usage

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> The domain_translation_struct debugfs node is used to dump the DMAR
> page
> tables for the PCI devices. It potentially races with setting domains to
> devices. The existing code uses the global spinlock device_domain_lock to
> avoid the races.
> 
> This removes the use of device_domain_lock outside of iommu.c by replacing
> it with the group mutex lock. Using the group mutex lock is cleaner and
> more compatible to following cleanups.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

[PATCH v3 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()

[Lu Baolu]

The disable_dmar_iommu() is called when IOMMU initialization fails or
the IOMMU is hot-removed from the system. In both cases, there is no
need to clear the IOMMU translation data structures for devices.

On the initialization path, the device probing only happens after the
IOMMU is initialized successfully, hence there're no translation data
structures.

On the hot-remove path, there is no real use case where the IOMMU is
hot-removed, but the devices that it manages are still alive in the
system. The translation data structures were torn down during device
release, hence there's no need to repeat it in IOMMU hot-remove path
either. This removes the unnecessary code and only leaves a check.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/pasid.h |  1 +
 drivers/iommu/intel/iommu.c | 21 +++++++--------------
 2 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/intel/pasid.h b/drivers/iommu/intel/pasid.h
index bf5b937848b4..20c54e50f533 100644
--- a/drivers/iommu/intel/pasid.h
+++ b/drivers/iommu/intel/pasid.h
@@ -39,6 +39,7 @@
  * only and pass-through transfer modes.
  */
 #define FLPT_DEFAULT_DID		1
+#define NUM_RESERVED_DID		2
 
 /*
  * The SUPERVISOR_MODE flag indicates a first level translation which
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 3b6571681bdd..43aaec5bdd84 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1716,23 +1716,16 @@ static int iommu_init_domains(struct intel_iommu *iommu)
 
 static void disable_dmar_iommu(struct intel_iommu *iommu)
 {
-	struct device_domain_info *info, *tmp;
-	unsigned long flags;
-
 	if (!iommu->domain_ids)
 		return;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
-	list_for_each_entry_safe(info, tmp, &device_domain_list, global) {
-		if (info->iommu != iommu)
-			continue;
-
-		if (!info->dev || !info->domain)
-			continue;
-
-		__dmar_remove_one_dev_info(info);
-	}
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	/*
+	 * All iommu domains must have been detached from the devices,
+	 * hence there should be no domain IDs in use.
+	 */
+	if (WARN_ON(bitmap_weight(iommu->domain_ids, cap_ndoms(iommu->cap))
+		    > NUM_RESERVED_DID))
+		return;
 
 	if (iommu->gcmd & DMA_GCMD_TE)
 		iommu_disable_translation(iommu);
-- 
2.25.1

RE: [PATCH v3 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> The disable_dmar_iommu() is called when IOMMU initialization fails or
> the IOMMU is hot-removed from the system. In both cases, there is no
> need to clear the IOMMU translation data structures for devices.
> 
> On the initialization path, the device probing only happens after the
> IOMMU is initialized successfully, hence there're no translation data
> structures.
> 
> On the hot-remove path, there is no real use case where the IOMMU is
> hot-removed, but the devices that it manages are still alive in the
> system. The translation data structures were torn down during device
> release, hence there's no need to repeat it in IOMMU hot-remove path
> either. This removes the unnecessary code and only leaves a check.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

You probably overlooked my last comment on kexec:

https://lore.kernel.org/lkml/BL1PR11MB52711A71AD9F11B7AE42694C8CAC9@BL1PR11MB5271.namprd11.prod.outlook.com/

I think my question is still not answered.

Re: [PATCH v3 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()

[Baolu Lu]

On 2022/7/1 15:58, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com> Sent: Wednesday, June 29,
>> 2022 3:47 PM
>> 
>> The disable_dmar_iommu() is called when IOMMU initialization fails
>> or the IOMMU is hot-removed from the system. In both cases, there
>> is no need to clear the IOMMU translation data structures for
>> devices.
>> 
>> On the initialization path, the device probing only happens after
>> the IOMMU is initialized successfully, hence there're no
>> translation data structures.
>> 
>> On the hot-remove path, there is no real use case where the IOMMU
>> is hot-removed, but the devices that it manages are still alive in
>> the system. The translation data structures were torn down during
>> device release, hence there's no need to repeat it in IOMMU
>> hot-remove path either. This removes the unnecessary code and only
>> leaves a check.
>> 
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> 
> You probably overlooked my last comment on kexec:
> 
> https://lore.kernel.org/lkml/BL1PR11MB52711A71AD9F11B7AE42694C8CAC9@BL1PR11MB5271.namprd11.prod.outlook.com/
>
>  I think my question is still not answered.

Sorry! I did overlook that comment. I can see your points now, though it
seems to be irrelevant to the problems that this series tries to solve.

The failure path of copying table still needs some improvement. At least
the pages allocated for root/context tables should be freed in the
failure path. Even worse, the software occupied a bit of page table
entry which is feasible for the old ECS, but not work for the new
scalable mode anymore.

All these problems deserve a separate series. We could address your
concerns there. Does this work for you?

Best regards,
baolu

RE: [PATCH v3 02/11] iommu/vt-d: Remove clearing translation data in disable_dmar_iommu()

[Tian, Kevin]

> From: Baolu Lu <baolu.lu@linux.intel.com>
> Sent: Sunday, July 3, 2022 12:34 PM
> 
> On 2022/7/1 15:58, Tian, Kevin wrote:
> >> From: Lu Baolu <baolu.lu@linux.intel.com> Sent: Wednesday, June 29,
> >> 2022 3:47 PM
> >>
> >> The disable_dmar_iommu() is called when IOMMU initialization fails
> >> or the IOMMU is hot-removed from the system. In both cases, there
> >> is no need to clear the IOMMU translation data structures for
> >> devices.
> >>
> >> On the initialization path, the device probing only happens after
> >> the IOMMU is initialized successfully, hence there're no
> >> translation data structures.
> >>
> >> On the hot-remove path, there is no real use case where the IOMMU
> >> is hot-removed, but the devices that it manages are still alive in
> >> the system. The translation data structures were torn down during
> >> device release, hence there's no need to repeat it in IOMMU
> >> hot-remove path either. This removes the unnecessary code and only
> >> leaves a check.
> >>
> >> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> >
> > You probably overlooked my last comment on kexec:
> >
> >
> https://lore.kernel.org/lkml/BL1PR11MB52711A71AD9F11B7AE42694C8CAC9
> @BL1PR11MB5271.namprd11.prod.outlook.com/
> >
> >  I think my question is still not answered.
> 
> Sorry! I did overlook that comment. I can see your points now, though it
> seems to be irrelevant to the problems that this series tries to solve.
> 
> The failure path of copying table still needs some improvement. At least
> the pages allocated for root/context tables should be freed in the
> failure path. Even worse, the software occupied a bit of page table
> entry which is feasible for the old ECS, but not work for the new
> scalable mode anymore.
> 
> All these problems deserve a separate series. We could address your
> concerns there. Does this work for you?

Yes, this makes sense to me.

[PATCH v3 03/11] iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk()

[Lu Baolu]

Use pci_get_domain_bus_and_slot() instead of searching the global list
to retrieve the pci device pointer. This also removes the global
device_domain_list as there isn't any consumer anymore.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.h |  1 -
 drivers/iommu/intel/iommu.c | 34 ++++++----------------------------
 2 files changed, 6 insertions(+), 29 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 8deb745d8b36..198c6c822ef4 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -609,7 +609,6 @@ struct intel_iommu {
 /* PCI domain-device relationship */
 struct device_domain_info {
 	struct list_head link;	/* link to domain siblings */
-	struct list_head global; /* link to global list */
 	u32 segment;		/* PCI segment number */
 	u8 bus;			/* PCI bus number */
 	u8 devfn;		/* PCI devfn number */
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 43aaec5bdd84..77915d61f7ec 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -131,8 +131,6 @@ static struct intel_iommu **g_iommus;
 
 static void __init check_tylersburg_isoch(void);
 static int rwbf_quirk;
-static inline struct device_domain_info *
-dmar_search_domain_by_dev_info(int segment, int bus, int devfn);
 
 /*
  * set to 1 to panic kernel if can't successfully enable VT-d
@@ -315,8 +313,6 @@ static int iommu_skip_te_disable;
 #define IDENTMAP_AZALIA		4
 
 static DEFINE_SPINLOCK(device_domain_lock);
-static LIST_HEAD(device_domain_list);
-
 const struct iommu_ops intel_iommu_ops;
 
 static bool translation_pre_enabled(struct intel_iommu *iommu)
@@ -846,9 +842,14 @@ static void pgtable_walk(struct intel_iommu *iommu, unsigned long pfn, u8 bus, u
 	struct device_domain_info *info;
 	struct dma_pte *parent, *pte;
 	struct dmar_domain *domain;
+	struct pci_dev *pdev;
 	int offset, level;
 
-	info = dmar_search_domain_by_dev_info(iommu->segment, bus, devfn);
+	pdev = pci_get_domain_bus_and_slot(iommu->segment, bus, devfn);
+	if (!pdev)
+		return;
+
+	info = dev_iommu_priv_get(&pdev->dev);
 	if (!info || !info->domain) {
 		pr_info("device [%02x:%02x.%d] not probed\n",
 			bus, PCI_SLOT(devfn), PCI_FUNC(devfn));
@@ -2357,19 +2358,6 @@ static void domain_remove_dev_info(struct dmar_domain *domain)
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
-static inline struct device_domain_info *
-dmar_search_domain_by_dev_info(int segment, int bus, int devfn)
-{
-	struct device_domain_info *info;
-
-	list_for_each_entry(info, &device_domain_list, global)
-		if (info->segment == segment && info->bus == bus &&
-		    info->devfn == devfn)
-			return info;
-
-	return NULL;
-}
-
 static int domain_setup_first_level(struct intel_iommu *iommu,
 				    struct dmar_domain *domain,
 				    struct device *dev,
@@ -4573,7 +4561,6 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 	struct pci_dev *pdev = dev_is_pci(dev) ? to_pci_dev(dev) : NULL;
 	struct device_domain_info *info;
 	struct intel_iommu *iommu;
-	unsigned long flags;
 	u8 bus, devfn;
 
 	iommu = device_to_iommu(dev, &bus, &devfn);
@@ -4616,10 +4603,7 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 		}
 	}
 
-	spin_lock_irqsave(&device_domain_lock, flags);
-	list_add(&info->global, &device_domain_list);
 	dev_iommu_priv_set(dev, info);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return &iommu->iommu;
 }
@@ -4627,15 +4611,9 @@ static struct iommu_device *intel_iommu_probe_device(struct device *dev)
 static void intel_iommu_release_device(struct device *dev)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	unsigned long flags;
 
 	dmar_remove_one_dev_info(dev);
-
-	spin_lock_irqsave(&device_domain_lock, flags);
 	dev_iommu_priv_set(dev, NULL);
-	list_del(&info->global);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
-
 	kfree(info);
 	set_dma_ops(dev, NULL);
 }
-- 
2.25.1

[PATCH v3 04/11] iommu/vt-d: Unnecessary spinlock for root table alloc and free

[Lu Baolu]

The IOMMU root table is allocated and freed in the IOMMU initialization
code in static boot or hot-remove paths. There's no need for a spinlock.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 77915d61f7ec..ff49c9460ede 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -809,14 +809,12 @@ static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
 
 static void free_context_table(struct intel_iommu *iommu)
 {
-	int i;
-	unsigned long flags;
 	struct context_entry *context;
+	int i;
+
+	if (!iommu->root_entry)
+		return;
 
-	spin_lock_irqsave(&iommu->lock, flags);
-	if (!iommu->root_entry) {
-		goto out;
-	}
 	for (i = 0; i < ROOT_ENTRY_NR; i++) {
 		context = iommu_context_addr(iommu, i, 0, 0);
 		if (context)
@@ -828,12 +826,10 @@ static void free_context_table(struct intel_iommu *iommu)
 		context = iommu_context_addr(iommu, i, 0x80, 0);
 		if (context)
 			free_pgtable_page(context);
-
 	}
+
 	free_pgtable_page(iommu->root_entry);
 	iommu->root_entry = NULL;
-out:
-	spin_unlock_irqrestore(&iommu->lock, flags);
 }
 
 #ifdef CONFIG_DMAR_DEBUG
@@ -1232,7 +1228,6 @@ static void domain_unmap(struct dmar_domain *domain, unsigned long start_pfn,
 static int iommu_alloc_root_entry(struct intel_iommu *iommu)
 {
 	struct root_entry *root;
-	unsigned long flags;
 
 	root = (struct root_entry *)alloc_pgtable_page(iommu->node);
 	if (!root) {
@@ -1242,10 +1237,7 @@ static int iommu_alloc_root_entry(struct intel_iommu *iommu)
 	}
 
 	__iommu_flush_cache(iommu, root, ROOT_SIZE);
-
-	spin_lock_irqsave(&iommu->lock, flags);
 	iommu->root_entry = root;
-	spin_unlock_irqrestore(&iommu->lock, flags);
 
 	return 0;
 }
-- 
2.25.1

[PATCH v3 05/11] iommu/vt-d: Replace spin_lock_irqsave() with spin_lock()

[Lu Baolu]

The iommu->lock is used to protect changes in root/context/pasid tables
and domain ID allocation. There's no use case to change these resources
in any interrupt context. Therefore, it's unnecessary to disable the
interrupts when the spinlock is held.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/debugfs.c |  6 ++----
 drivers/iommu/intel/iommu.c   | 26 +++++++++++---------------
 drivers/iommu/intel/svm.c     |  6 +++---
 3 files changed, 16 insertions(+), 22 deletions(-)

diff --git a/drivers/iommu/intel/debugfs.c b/drivers/iommu/intel/debugfs.c
index 6e1a3f88abc8..1f925285104e 100644
--- a/drivers/iommu/intel/debugfs.c
+++ b/drivers/iommu/intel/debugfs.c
@@ -263,10 +263,9 @@ static void ctx_tbl_walk(struct seq_file *m, struct intel_iommu *iommu, u16 bus)
 
 static void root_tbl_walk(struct seq_file *m, struct intel_iommu *iommu)
 {
-	unsigned long flags;
 	u16 bus;
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	spin_lock(&iommu->lock);
 	seq_printf(m, "IOMMU %s: Root Table Address: 0x%llx\n", iommu->name,
 		   (u64)virt_to_phys(iommu->root_entry));
 	seq_puts(m, "B.D.F\tRoot_entry\t\t\t\tContext_entry\t\t\t\tPASID\tPASID_table_entry\n");
@@ -278,8 +277,7 @@ static void root_tbl_walk(struct seq_file *m, struct intel_iommu *iommu)
 	 */
 	for (bus = 0; bus < 256; bus++)
 		ctx_tbl_walk(m, iommu, bus);
-
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	spin_unlock(&iommu->lock);
 }
 
 static int dmar_translation_struct_show(struct seq_file *m, void *unused)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index ff49c9460ede..a81bdddf1091 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -797,13 +797,12 @@ static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
 {
 	struct context_entry *context;
 	int ret = 0;
-	unsigned long flags;
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	spin_lock(&iommu->lock);
 	context = iommu_context_addr(iommu, bus, devfn, 0);
 	if (context)
 		ret = context_present(context);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	spin_unlock(&iommu->lock);
 	return ret;
 }
 
@@ -2296,16 +2295,15 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8
 {
 	struct intel_iommu *iommu = info->iommu;
 	struct context_entry *context;
-	unsigned long flags;
 	u16 did_old;
 
 	if (!iommu)
 		return;
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	spin_lock(&iommu->lock);
 	context = iommu_context_addr(iommu, bus, devfn, 0);
 	if (!context) {
-		spin_unlock_irqrestore(&iommu->lock, flags);
+		spin_unlock(&iommu->lock);
 		return;
 	}
 
@@ -2320,7 +2318,7 @@ static void domain_context_clear_one(struct device_domain_info *info, u8 bus, u8
 
 	context_clear_entry(context);
 	__iommu_flush_cache(iommu, context, sizeof(*context));
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	spin_unlock(&iommu->lock);
 	iommu->flush.flush_context(iommu,
 				   did_old,
 				   (((u16)bus) << 8) | devfn,
@@ -2499,7 +2497,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		}
 
 		/* Setup the PASID entry for requests without PASID: */
-		spin_lock_irqsave(&iommu->lock, flags);
+		spin_lock(&iommu->lock);
 		if (hw_pass_through && domain_type_is_si(domain))
 			ret = intel_pasid_setup_pass_through(iommu, domain,
 					dev, PASID_RID2PASID);
@@ -2509,7 +2507,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		else
 			ret = intel_pasid_setup_second_level(iommu, domain,
 					dev, PASID_RID2PASID);
-		spin_unlock_irqrestore(&iommu->lock, flags);
+		spin_unlock(&iommu->lock);
 		if (ret) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			dmar_remove_one_dev_info(dev);
@@ -2777,7 +2775,6 @@ static int copy_translation_tables(struct intel_iommu *iommu)
 	struct root_entry *old_rt;
 	phys_addr_t old_rt_phys;
 	int ctxt_table_entries;
-	unsigned long flags;
 	u64 rtaddr_reg;
 	int bus, ret;
 	bool new_ext, ext;
@@ -2820,7 +2817,7 @@ static int copy_translation_tables(struct intel_iommu *iommu)
 		}
 	}
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	spin_lock(&iommu->lock);
 
 	/* Context tables are copied, now write them to the root_entry table */
 	for (bus = 0; bus < 256; bus++) {
@@ -2839,7 +2836,7 @@ static int copy_translation_tables(struct intel_iommu *iommu)
 		iommu->root_entry[bus].hi = val;
 	}
 
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	spin_unlock(&iommu->lock);
 
 	kfree(ctxt_tbls);
 
@@ -4166,7 +4163,6 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 {
 	struct dmar_domain *domain;
 	struct intel_iommu *iommu;
-	unsigned long flags;
 
 	assert_spin_locked(&device_domain_lock);
 
@@ -4188,9 +4184,9 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 
 	list_del(&info->link);
 
-	spin_lock_irqsave(&iommu->lock, flags);
+	spin_lock(&iommu->lock);
 	domain_detach_iommu(domain, iommu);
-	spin_unlock_irqrestore(&iommu->lock, flags);
+	spin_unlock(&iommu->lock);
 }
 
 static void dmar_remove_one_dev_info(struct device *dev)
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 580713aa9e07..82288a50660d 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -328,9 +328,9 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 					   unsigned int flags)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	unsigned long iflags, sflags;
 	struct intel_svm_dev *sdev;
 	struct intel_svm *svm;
+	unsigned long sflags;
 	int ret = 0;
 
 	svm = pasid_private_find(mm->pasid);
@@ -394,10 +394,10 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 	sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ?
 			PASID_FLAG_SUPERVISOR_MODE : 0;
 	sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
-	spin_lock_irqsave(&iommu->lock, iflags);
+	spin_lock(&iommu->lock);
 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
 					    FLPT_DEFAULT_DID, sflags);
-	spin_unlock_irqrestore(&iommu->lock, iflags);
+	spin_unlock(&iommu->lock);
 
 	if (ret)
 		goto free_sdev;
-- 
2.25.1

[PATCH v3 06/11] iommu/vt-d: Acquiring lock in domain ID allocation helpers

[Lu Baolu]

The iommu->lock is used to protect the per-IOMMU domain ID resource.
Moving the lock into the ID alloc/free helpers makes the code more
compact. At the same time, the device_domain_lock is irrelevant to
the domain ID resource, remove its assertion as well.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 24 +++++++++---------------
 1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index a81bdddf1091..5681b8ef11f1 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -1781,16 +1781,13 @@ static struct dmar_domain *alloc_domain(unsigned int type)
 	return domain;
 }
 
-/* Must be called with iommu->lock */
 static int domain_attach_iommu(struct dmar_domain *domain,
 			       struct intel_iommu *iommu)
 {
 	unsigned long ndomains;
-	int num;
-
-	assert_spin_locked(&device_domain_lock);
-	assert_spin_locked(&iommu->lock);
+	int num, ret = 0;
 
+	spin_lock(&iommu->lock);
 	domain->iommu_refcnt[iommu->seq_id] += 1;
 	if (domain->iommu_refcnt[iommu->seq_id] == 1) {
 		ndomains = cap_ndoms(iommu->cap);
@@ -1799,7 +1796,8 @@ static int domain_attach_iommu(struct dmar_domain *domain,
 		if (num >= ndomains) {
 			pr_err("%s: No free domain ids\n", iommu->name);
 			domain->iommu_refcnt[iommu->seq_id] -= 1;
-			return -ENOSPC;
+			ret = -ENOSPC;
+			goto out_unlock;
 		}
 
 		set_bit(num, iommu->domain_ids);
@@ -1808,7 +1806,9 @@ static int domain_attach_iommu(struct dmar_domain *domain,
 		domain_update_iommu_cap(domain);
 	}
 
-	return 0;
+out_unlock:
+	spin_unlock(&iommu->lock);
+	return ret;
 }
 
 static void domain_detach_iommu(struct dmar_domain *domain,
@@ -1816,9 +1816,7 @@ static void domain_detach_iommu(struct dmar_domain *domain,
 {
 	int num;
 
-	assert_spin_locked(&device_domain_lock);
-	assert_spin_locked(&iommu->lock);
-
+	spin_lock(&iommu->lock);
 	domain->iommu_refcnt[iommu->seq_id] -= 1;
 	if (domain->iommu_refcnt[iommu->seq_id] == 0) {
 		num = domain->iommu_did[iommu->seq_id];
@@ -1826,6 +1824,7 @@ static void domain_detach_iommu(struct dmar_domain *domain,
 		domain_update_iommu_cap(domain);
 		domain->iommu_did[iommu->seq_id] = 0;
 	}
+	spin_unlock(&iommu->lock);
 }
 
 static inline int guestwidth_to_adjustwidth(int gaw)
@@ -2477,9 +2476,7 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 
 	spin_lock_irqsave(&device_domain_lock, flags);
 	info->domain = domain;
-	spin_lock(&iommu->lock);
 	ret = domain_attach_iommu(domain, iommu);
-	spin_unlock(&iommu->lock);
 	if (ret) {
 		spin_unlock_irqrestore(&device_domain_lock, flags);
 		return ret;
@@ -4183,10 +4180,7 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 	}
 
 	list_del(&info->link);
-
-	spin_lock(&iommu->lock);
 	domain_detach_iommu(domain, iommu);
-	spin_unlock(&iommu->lock);
 }
 
 static void dmar_remove_one_dev_info(struct device *dev)
-- 
2.25.1

RE: [PATCH v3 06/11] iommu/vt-d: Acquiring lock in domain ID allocation helpers

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> The iommu->lock is used to protect the per-IOMMU domain ID resource.
> Moving the lock into the ID alloc/free helpers makes the code more
> compact. At the same time, the device_domain_lock is irrelevant to
> the domain ID resource, remove its assertion as well.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

[PATCH v3 07/11] iommu/vt-d: Acquiring lock in pasid manipulation helpers

[Lu Baolu]

The iommu->lock is used to protect the per-IOMMU pasid directory table
and pasid table. Move the spinlock acquisition/release into the helpers
to make the code self-contained.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.c |   2 -
 drivers/iommu/intel/pasid.c | 103 +++++++++++++++++++-----------------
 drivers/iommu/intel/svm.c   |   3 --
 3 files changed, 55 insertions(+), 53 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5681b8ef11f1..f45a769695c3 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2494,7 +2494,6 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		}
 
 		/* Setup the PASID entry for requests without PASID: */
-		spin_lock(&iommu->lock);
 		if (hw_pass_through && domain_type_is_si(domain))
 			ret = intel_pasid_setup_pass_through(iommu, domain,
 					dev, PASID_RID2PASID);
@@ -2504,7 +2503,6 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		else
 			ret = intel_pasid_setup_second_level(iommu, domain,
 					dev, PASID_RID2PASID);
-		spin_unlock(&iommu->lock);
 		if (ret) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			dmar_remove_one_dev_info(dev);
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 43f090381ec7..7792a1b2ebc4 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -450,17 +450,17 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device *dev,
 	struct pasid_entry *pte;
 	u16 did, pgtt;
 
+	spin_lock(&iommu->lock);
 	pte = intel_pasid_get_entry(dev, pasid);
-	if (WARN_ON(!pte))
-		return;
-
-	if (!pasid_pte_is_present(pte))
+	if (WARN_ON(!pte) || !pasid_pte_is_present(pte)) {
+		spin_unlock(&iommu->lock);
 		return;
+	}
 
 	did = pasid_get_domain_id(pte);
 	pgtt = pasid_pte_get_pgtt(pte);
-
 	intel_pasid_clear_entry(dev, pasid, fault_ignore);
+	spin_unlock(&iommu->lock);
 
 	if (!ecap_coherent(iommu->ecap))
 		clflush_cache_range(pte, sizeof(*pte));
@@ -496,22 +496,6 @@ static void pasid_flush_caches(struct intel_iommu *iommu,
 	}
 }
 
-static inline int pasid_enable_wpe(struct pasid_entry *pte)
-{
-#ifdef CONFIG_X86
-	unsigned long cr0 = read_cr0();
-
-	/* CR0.WP is normally set but just to be sure */
-	if (unlikely(!(cr0 & X86_CR0_WP))) {
-		pr_err_ratelimited("No CPU write protect!\n");
-		return -EINVAL;
-	}
-#endif
-	pasid_set_wpe(pte);
-
-	return 0;
-};
-
 /*
  * Set up the scalable mode pasid table entry for first only
  * translation type.
@@ -528,39 +512,52 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 		return -EINVAL;
 	}
 
-	pte = intel_pasid_get_entry(dev, pasid);
-	if (WARN_ON(!pte))
+	if (flags & PASID_FLAG_SUPERVISOR_MODE) {
+#ifdef CONFIG_X86
+		unsigned long cr0 = read_cr0();
+
+		/* CR0.WP is normally set but just to be sure */
+		if (unlikely(!(cr0 & X86_CR0_WP))) {
+			pr_err("No CPU write protect!\n");
+			return -EINVAL;
+		}
+#endif
+		if (!ecap_srs(iommu->ecap)) {
+			pr_err("No supervisor request support on %s\n",
+			       iommu->name);
+			return -EINVAL;
+		}
+	}
+
+	if ((flags & PASID_FLAG_FL5LP) && !cap_5lp_support(iommu->cap)) {
+		pr_err("No 5-level paging support for first-level on %s\n",
+		       iommu->name);
 		return -EINVAL;
+	}
 
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+	spin_lock(&iommu->lock);
+	pte = intel_pasid_get_entry(dev, pasid);
+	if (!pte) {
+		spin_unlock(&iommu->lock);
+		return -ENODEV;
+	}
+
+	if (pasid_pte_is_present(pte)) {
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 
 	/* Setup the first level page table pointer: */
 	pasid_set_flptr(pte, (u64)__pa(pgd));
 	if (flags & PASID_FLAG_SUPERVISOR_MODE) {
-		if (!ecap_srs(iommu->ecap)) {
-			pr_err("No supervisor request support on %s\n",
-			       iommu->name);
-			return -EINVAL;
-		}
 		pasid_set_sre(pte);
-		if (pasid_enable_wpe(pte))
-			return -EINVAL;
-
+		pasid_set_wpe(pte);
 	}
 
-	if (flags & PASID_FLAG_FL5LP) {
-		if (cap_5lp_support(iommu->cap)) {
-			pasid_set_flpm(pte, 1);
-		} else {
-			pr_err("No 5-level paging support for first-level\n");
-			pasid_clear_entry(pte);
-			return -EINVAL;
-		}
-	}
+	if (flags & PASID_FLAG_FL5LP)
+		pasid_set_flpm(pte, 1);
 
 	if (flags & PASID_FLAG_PAGE_SNOOP)
 		pasid_set_pgsnp(pte);
@@ -572,6 +569,8 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 	/* Setup Present and PASID Granular Transfer Type: */
 	pasid_set_translation_type(pte, PASID_ENTRY_PGTT_FL_ONLY);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
@@ -629,15 +628,17 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	pgd_val = virt_to_phys(pgd);
 	did = domain->iommu_did[iommu->seq_id];
 
+	spin_lock(&iommu->lock);
 	pte = intel_pasid_get_entry(dev, pasid);
 	if (!pte) {
-		dev_err(dev, "Failed to get pasid entry of PASID %d\n", pasid);
+		spin_unlock(&iommu->lock);
 		return -ENODEV;
 	}
 
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+	if (pasid_pte_is_present(pte)) {
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 	pasid_set_domain_id(pte, did);
@@ -654,6 +655,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	if (pasid != PASID_RID2PASID)
 		pasid_set_sre(pte);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
@@ -669,15 +672,17 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
 	u16 did = FLPT_DEFAULT_DID;
 	struct pasid_entry *pte;
 
+	spin_lock(&iommu->lock);
 	pte = intel_pasid_get_entry(dev, pasid);
 	if (!pte) {
-		dev_err(dev, "Failed to get pasid entry of PASID %d\n", pasid);
+		spin_unlock(&iommu->lock);
 		return -ENODEV;
 	}
 
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+	if (pasid_pte_is_present(pte)) {
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 	pasid_set_domain_id(pte, did);
@@ -692,6 +697,8 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
 	 */
 	pasid_set_sre(pte);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 82288a50660d..64072e628bbd 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -394,11 +394,8 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 	sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ?
 			PASID_FLAG_SUPERVISOR_MODE : 0;
 	sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
-	spin_lock(&iommu->lock);
 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
 					    FLPT_DEFAULT_DID, sflags);
-	spin_unlock(&iommu->lock);
-
 	if (ret)
 		goto free_sdev;
 
-- 
2.25.1

[PATCH v3 08/11] iommu/vt-d: Check device list of domain in domain free path

[Lu Baolu]

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>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.c | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index f45a769695c3..94f41981b75b 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);
 
@@ -1843,10 +1842,6 @@ 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 (domain->pgd) {
 		LIST_HEAD(freelist);
 
@@ -1854,6 +1849,9 @@ static void domain_exit(struct dmar_domain *domain)
 		put_pages_list(&freelist);
 	}
 
+	if (WARN_ON(!list_empty(&domain->devices)))
+		return;
+
 	kfree(domain);
 }
 
@@ -2336,17 +2334,6 @@ 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

[PATCH v3 09/11] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller

[Lu Baolu]

Fold __dmar_remove_one_dev_info() into dmar_remove_one_dev_info() which
is its only caller. Make the spin lock critical range only cover the
device list change code and remove some unnecessary checks.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 33 ++++++++-------------------------
 1 file changed, 8 insertions(+), 25 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 94f41981b75b..3038aafecff9 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -295,7 +295,6 @@ static LIST_HEAD(dmar_satc_units);
 static int g_num_of_iommus;
 
 static void dmar_remove_one_dev_info(struct device *dev);
-static void __dmar_remove_one_dev_info(struct device_domain_info *info);
 
 int dmar_disabled = !IS_ENABLED(CONFIG_INTEL_IOMMU_DEFAULT_ON);
 int intel_iommu_sm = IS_ENABLED(CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON);
@@ -4141,20 +4140,13 @@ static void domain_context_clear(struct device_domain_info *info)
 			       &domain_context_clear_one_cb, info);
 }
 
-static void __dmar_remove_one_dev_info(struct device_domain_info *info)
+static void dmar_remove_one_dev_info(struct device *dev)
 {
-	struct dmar_domain *domain;
-	struct intel_iommu *iommu;
-
-	assert_spin_locked(&device_domain_lock);
-
-	if (WARN_ON(!info))
-		return;
-
-	iommu = info->iommu;
-	domain = info->domain;
+	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct intel_iommu *iommu = info->iommu;
+	unsigned long flags;
 
-	if (info->dev && !dev_is_real_dma_subdevice(info->dev)) {
+	if (!dev_is_real_dma_subdevice(info->dev)) {
 		if (dev_is_pci(info->dev) && sm_supported(iommu))
 			intel_pasid_tear_down_entry(iommu, info->dev,
 					PASID_RID2PASID, false);
@@ -4164,20 +4156,11 @@ static void __dmar_remove_one_dev_info(struct device_domain_info *info)
 		intel_pasid_free_table(info->dev);
 	}
 
-	list_del(&info->link);
-	domain_detach_iommu(domain, iommu);
-}
-
-static void dmar_remove_one_dev_info(struct device *dev)
-{
-	struct device_domain_info *info;
-	unsigned long flags;
-
 	spin_lock_irqsave(&device_domain_lock, flags);
-	info = dev_iommu_priv_get(dev);
-	if (info)
-		__dmar_remove_one_dev_info(info);
+	list_del(&info->link);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
+
+	domain_detach_iommu(info->domain, iommu);
 }
 
 static int md_domain_init(struct dmar_domain *domain, int guest_width)
-- 
2.25.1

RE: [PATCH v3 09/11] iommu/vt-d: Fold __dmar_remove_one_dev_info() into its caller

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> Fold __dmar_remove_one_dev_info() into dmar_remove_one_dev_info()
> which
> is its only caller. Make the spin lock critical range only cover the
> device list change code and remove some unnecessary checks.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

[PATCH v3 10/11] iommu/vt-d: Use device_domain_lock accurately

[Lu Baolu]

The device_domain_lock is used to protect the device tracking list of
a domain. Remove unnecessary spin_lock/unlock()'s and move the necessary
ones around the list access.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.c | 61 ++++++++++++++-----------------------
 1 file changed, 23 insertions(+), 38 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 3038aafecff9..1783859b511a 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -534,16 +534,10 @@ static int domain_update_device_node(struct dmar_domain *domain)
 {
 	struct device_domain_info *info;
 	int nid = NUMA_NO_NODE;
+	unsigned long flags;
 
-	assert_spin_locked(&device_domain_lock);
-
-	if (list_empty(&domain->devices))
-		return NUMA_NO_NODE;
-
+	spin_lock_irqsave(&device_domain_lock, flags);
 	list_for_each_entry(info, &domain->devices, link) {
-		if (!info->dev)
-			continue;
-
 		/*
 		 * There could possibly be multiple device numa nodes as devices
 		 * within the same domain may sit behind different IOMMUs. There
@@ -554,6 +548,7 @@ static int domain_update_device_node(struct dmar_domain *domain)
 		if (nid != NUMA_NO_NODE)
 			break;
 	}
+	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return nid;
 }
@@ -1376,23 +1371,24 @@ static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
 }
 
 static struct device_domain_info *
-iommu_support_dev_iotlb (struct dmar_domain *domain, struct intel_iommu *iommu,
-			 u8 bus, u8 devfn)
+iommu_support_dev_iotlb(struct dmar_domain *domain, struct intel_iommu *iommu,
+			u8 bus, u8 devfn)
 {
 	struct device_domain_info *info;
-
-	assert_spin_locked(&device_domain_lock);
+	unsigned long flags;
 
 	if (!iommu->qi)
 		return NULL;
 
-	list_for_each_entry(info, &domain->devices, link)
+	spin_lock_irqsave(&device_domain_lock, flags);
+	list_for_each_entry(info, &domain->devices, link) {
 		if (info->iommu == iommu && info->bus == bus &&
 		    info->devfn == devfn) {
-			if (info->ats_supported && info->dev)
-				return info;
-			break;
+			spin_unlock_irqrestore(&device_domain_lock, flags);
+			return info->ats_supported ? info : NULL;
 		}
+	}
+	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return NULL;
 }
@@ -1401,24 +1397,23 @@ static void domain_update_iotlb(struct dmar_domain *domain)
 {
 	struct device_domain_info *info;
 	bool has_iotlb_device = false;
+	unsigned long flags;
 
-	assert_spin_locked(&device_domain_lock);
-
-	list_for_each_entry(info, &domain->devices, link)
+	spin_lock_irqsave(&device_domain_lock, flags);
+	list_for_each_entry(info, &domain->devices, link) {
 		if (info->ats_enabled) {
 			has_iotlb_device = true;
 			break;
 		}
-
+	}
 	domain->has_iotlb_device = has_iotlb_device;
+	spin_unlock_irqrestore(&device_domain_lock, flags);
 }
 
 static void iommu_enable_dev_iotlb(struct device_domain_info *info)
 {
 	struct pci_dev *pdev;
 
-	assert_spin_locked(&device_domain_lock);
-
 	if (!info || !dev_is_pci(info->dev))
 		return;
 
@@ -1464,8 +1459,6 @@ static void iommu_disable_dev_iotlb(struct device_domain_info *info)
 {
 	struct pci_dev *pdev;
 
-	assert_spin_locked(&device_domain_lock);
-
 	if (!dev_is_pci(info->dev))
 		return;
 
@@ -1908,11 +1901,11 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 				      struct pasid_table *table,
 				      u8 bus, u8 devfn)
 {
+	struct device_domain_info *info =
+			iommu_support_dev_iotlb(domain, iommu, bus, devfn);
 	u16 did = domain->iommu_did[iommu->seq_id];
 	int translation = CONTEXT_TT_MULTI_LEVEL;
-	struct device_domain_info *info = NULL;
 	struct context_entry *context;
-	unsigned long flags;
 	int ret;
 
 	WARN_ON(did == 0);
@@ -1925,7 +1918,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 
 	BUG_ON(!domain->pgd);
 
-	spin_lock_irqsave(&device_domain_lock, flags);
 	spin_lock(&iommu->lock);
 
 	ret = -ENOMEM;
@@ -1978,7 +1970,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 		 * Setup the Device-TLB enable bit and Page request
 		 * Enable bit:
 		 */
-		info = iommu_support_dev_iotlb(domain, iommu, bus, devfn);
 		if (info && info->ats_supported)
 			context_set_sm_dte(context);
 		if (info && info->pri_supported)
@@ -2001,7 +1992,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 					goto out_unlock;
 			}
 
-			info = iommu_support_dev_iotlb(domain, iommu, bus, devfn);
 			if (info && info->ats_supported)
 				translation = CONTEXT_TT_DEV_IOTLB;
 			else
@@ -2047,7 +2037,6 @@ static int domain_context_mapping_one(struct dmar_domain *domain,
 
 out_unlock:
 	spin_unlock(&iommu->lock);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return ret;
 }
@@ -2460,13 +2449,12 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 	if (!iommu)
 		return -ENODEV;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
-	info->domain = domain;
 	ret = domain_attach_iommu(domain, iommu);
-	if (ret) {
-		spin_unlock_irqrestore(&device_domain_lock, flags);
+	if (ret)
 		return ret;
-	}
+
+	info->domain = domain;
+	spin_lock_irqsave(&device_domain_lock, flags);
 	list_add(&info->link, &domain->devices);
 	spin_unlock_irqrestore(&device_domain_lock, flags);
 
@@ -4636,7 +4624,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct context_entry *context;
 	struct dmar_domain *domain;
-	unsigned long flags;
 	u64 ctx_lo;
 	int ret;
 
@@ -4644,7 +4631,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
 	if (!domain)
 		return -EINVAL;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
 	spin_lock(&iommu->lock);
 
 	ret = -EINVAL;
@@ -4676,7 +4662,6 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct device *dev)
 
  out:
 	spin_unlock(&iommu->lock);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return ret;
 }
-- 
2.25.1

RE: [PATCH v3 10/11] iommu/vt-d: Use device_domain_lock accurately

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> +	spin_lock_irqsave(&device_domain_lock, flags);
>  	list_for_each_entry(info, &domain->devices, link) {
> -		if (!info->dev)
> -			continue;
> -

suppose you can replace all spin_lock_irqsave() with spin_lock()
in patch5 instead of leaving some replacement to next patch.

Re: [PATCH v3 10/11] iommu/vt-d: Use device_domain_lock accurately

[Baolu Lu]

On 2022/7/1 16:15, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Wednesday, June 29, 2022 3:47 PM
>>
>> +	spin_lock_irqsave(&device_domain_lock, flags);
>>   	list_for_each_entry(info, &domain->devices, link) {
>> -		if (!info->dev)
>> -			continue;
>> -
> 
> suppose you can replace all spin_lock_irqsave() with spin_lock()
> in patch5 instead of leaving some replacement to next patch.
> 

Make sense. I will update the series.

Best regards,
baolu

Re: [PATCH v3 10/11] iommu/vt-d: Use device_domain_lock accurately

[Baolu Lu]

On 2022/7/1 16:15, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Wednesday, June 29, 2022 3:47 PM
>>
>> +	spin_lock_irqsave(&device_domain_lock, flags);
>>   	list_for_each_entry(info, &domain->devices, link) {
>> -		if (!info->dev)
>> -			continue;
>> -
> 
> suppose you can replace all spin_lock_irqsave() with spin_lock()
> in patch5 instead of leaving some replacement to next patch.
> 

Make sense to me. Will update this.

Best regards,
baolu

[PATCH v3 11/11] iommu/vt-d: Convert global spinlock into per domain lock

[Lu Baolu]

Using a global device_domain_lock spinlock to protect per-domain device
tracking lists is an inefficient way, especially considering this lock
is also needed in the hot paths. This optimizes the locking mechanism
by converting the global lock to per domain lock.

On the other hand, as the device tracking lists are never accessed in
any interrupt context, there is no need to disable interrupts while
spinning. Replace irqsave variant with spinlock calls.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel/iommu.h |  1 +
 drivers/iommu/intel/iommu.c | 50 ++++++++++++++++---------------------
 2 files changed, 22 insertions(+), 29 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 198c6c822ef4..df64d3d9c49a 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -541,6 +541,7 @@ struct dmar_domain {
 	u8 force_snooping : 1;		/* Create IOPTEs with snoop control */
 	u8 set_pte_snp:1;
 
+	spinlock_t lock;		/* Protect device tracking lists */
 	struct list_head devices;	/* all devices' list */
 
 	struct dma_pte	*pgd;		/* virtual address */
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 1783859b511a..da6cfea0f0d6 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -310,7 +310,6 @@ static int iommu_skip_te_disable;
 #define IDENTMAP_GFX		2
 #define IDENTMAP_AZALIA		4
 
-static DEFINE_SPINLOCK(device_domain_lock);
 const struct iommu_ops intel_iommu_ops;
 
 static bool translation_pre_enabled(struct intel_iommu *iommu)
@@ -534,9 +533,8 @@ static int domain_update_device_node(struct dmar_domain *domain)
 {
 	struct device_domain_info *info;
 	int nid = NUMA_NO_NODE;
-	unsigned long flags;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_for_each_entry(info, &domain->devices, link) {
 		/*
 		 * There could possibly be multiple device numa nodes as devices
@@ -548,7 +546,7 @@ static int domain_update_device_node(struct dmar_domain *domain)
 		if (nid != NUMA_NO_NODE)
 			break;
 	}
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 
 	return nid;
 }
@@ -1375,20 +1373,19 @@ iommu_support_dev_iotlb(struct dmar_domain *domain, struct intel_iommu *iommu,
 			u8 bus, u8 devfn)
 {
 	struct device_domain_info *info;
-	unsigned long flags;
 
 	if (!iommu->qi)
 		return NULL;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_for_each_entry(info, &domain->devices, link) {
 		if (info->iommu == iommu && info->bus == bus &&
 		    info->devfn == devfn) {
-			spin_unlock_irqrestore(&device_domain_lock, flags);
+			spin_unlock(&domain->lock);
 			return info->ats_supported ? info : NULL;
 		}
 	}
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 
 	return NULL;
 }
@@ -1397,9 +1394,8 @@ static void domain_update_iotlb(struct dmar_domain *domain)
 {
 	struct device_domain_info *info;
 	bool has_iotlb_device = false;
-	unsigned long flags;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_for_each_entry(info, &domain->devices, link) {
 		if (info->ats_enabled) {
 			has_iotlb_device = true;
@@ -1407,7 +1403,7 @@ static void domain_update_iotlb(struct dmar_domain *domain)
 		}
 	}
 	domain->has_iotlb_device = has_iotlb_device;
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 }
 
 static void iommu_enable_dev_iotlb(struct device_domain_info *info)
@@ -1498,17 +1494,15 @@ static void __iommu_flush_dev_iotlb(struct device_domain_info *info,
 static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
 				  u64 addr, unsigned mask)
 {
-	unsigned long flags;
 	struct device_domain_info *info;
 
 	if (!domain->has_iotlb_device)
 		return;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_for_each_entry(info, &domain->devices, link)
 		__iommu_flush_dev_iotlb(info, addr, mask);
-
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 }
 
 static void iommu_flush_iotlb_psi(struct intel_iommu *iommu,
@@ -1768,6 +1762,7 @@ static struct dmar_domain *alloc_domain(unsigned int type)
 		domain->flags |= DOMAIN_FLAG_USE_FIRST_LEVEL;
 	domain->has_iotlb_device = false;
 	INIT_LIST_HEAD(&domain->devices);
+	spin_lock_init(&domain->lock);
 
 	return domain;
 }
@@ -2441,7 +2436,6 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct intel_iommu *iommu;
-	unsigned long flags;
 	u8 bus, devfn;
 	int ret;
 
@@ -2454,9 +2448,9 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		return ret;
 
 	info->domain = domain;
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_add(&info->link, &domain->devices);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 
 	/* PASID table is mandatory for a PCI device in scalable mode. */
 	if (sm_supported(iommu) && !dev_is_real_dma_subdevice(dev)) {
@@ -4131,8 +4125,8 @@ static void domain_context_clear(struct device_domain_info *info)
 static void dmar_remove_one_dev_info(struct device *dev)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
+	struct dmar_domain *domain = info->domain;
 	struct intel_iommu *iommu = info->iommu;
-	unsigned long flags;
 
 	if (!dev_is_real_dma_subdevice(info->dev)) {
 		if (dev_is_pci(info->dev) && sm_supported(iommu))
@@ -4144,11 +4138,11 @@ static void dmar_remove_one_dev_info(struct device *dev)
 		intel_pasid_free_table(info->dev);
 	}
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&domain->lock);
 	list_del(&info->link);
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&domain->lock);
 
-	domain_detach_iommu(info->domain, iommu);
+	domain_detach_iommu(domain, iommu);
 }
 
 static int md_domain_init(struct dmar_domain *domain, int guest_width)
@@ -4430,7 +4424,7 @@ static bool domain_support_force_snooping(struct dmar_domain *domain)
 	struct device_domain_info *info;
 	bool support = true;
 
-	assert_spin_locked(&device_domain_lock);
+	assert_spin_locked(&domain->lock);
 	list_for_each_entry(info, &domain->devices, link) {
 		if (!ecap_sc_support(info->iommu->ecap)) {
 			support = false;
@@ -4445,8 +4439,7 @@ static void domain_set_force_snooping(struct dmar_domain *domain)
 {
 	struct device_domain_info *info;
 
-	assert_spin_locked(&device_domain_lock);
-
+	assert_spin_locked(&domain->lock);
 	/*
 	 * Second level page table supports per-PTE snoop control. The
 	 * iommu_map() interface will handle this by setting SNP bit.
@@ -4464,20 +4457,19 @@ static void domain_set_force_snooping(struct dmar_domain *domain)
 static bool intel_iommu_enforce_cache_coherency(struct iommu_domain *domain)
 {
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
-	unsigned long flags;
 
 	if (dmar_domain->force_snooping)
 		return true;
 
-	spin_lock_irqsave(&device_domain_lock, flags);
+	spin_lock(&dmar_domain->lock);
 	if (!domain_support_force_snooping(dmar_domain)) {
-		spin_unlock_irqrestore(&device_domain_lock, flags);
+		spin_unlock(&dmar_domain->lock);
 		return false;
 	}
 
 	domain_set_force_snooping(dmar_domain);
 	dmar_domain->force_snooping = true;
-	spin_unlock_irqrestore(&device_domain_lock, flags);
+	spin_unlock(&dmar_domain->lock);
 
 	return true;
 }
-- 
2.25.1

RE: [PATCH v3 11/11] iommu/vt-d: Convert global spinlock into per domain lock

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> Using a global device_domain_lock spinlock to protect per-domain device
> tracking lists is an inefficient way, especially considering this lock
> is also needed in the hot paths. This optimizes the locking mechanism
> by converting the global lock to per domain lock.
> 
> On the other hand, as the device tracking lists are never accessed in
> any interrupt context, there is no need to disable interrupts while
> spinning. Replace irqsave variant with spinlock calls.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

except the previous comment on where to convert spin_lock_irqsave()
the rest looks good to me.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

RE: [PATCH v3 00/11] iommu/vt-d: Optimize the use of locks

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Wednesday, June 29, 2022 3:47 PM
> 
> v3:
>  - Split reduction of lock ranges from changing irqsave.
>    https://lore.kernel.org/linux-
> iommu/BN9PR11MB52760A3D7C6BF1AF9C9D34658CAA9@BN9PR11MB5276.
> namprd11.prod.outlook.com/
>  - Fully initialize the dev_info before adding it to the list.
>    https://lore.kernel.org/linux-
> iommu/BN9PR11MB52764D7CD86448C5E4EB46668CAA9@BN9PR11MB5276.
> namprd11.prod.outlook.com/
>  - Various code and comments refinement.
> 

This doesn't say why original patch2 was removed:

	"iommu/vt-d: Remove for_each_device_domain()"

It took me a while to realize that it's already covered by your another
patch fixing RID2PASID. 😊

Re: [PATCH v3 00/11] iommu/vt-d: Optimize the use of locks

[Baolu Lu]

On 2022/7/1 15:53, Tian, Kevin wrote:
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>> Sent: Wednesday, June 29, 2022 3:47 PM
>>
>> v3:
>>   - Split reduction of lock ranges from changing irqsave.
>>     https://lore.kernel.org/linux-
>> iommu/BN9PR11MB52760A3D7C6BF1AF9C9D34658CAA9@BN9PR11MB5276.
>> namprd11.prod.outlook.com/
>>   - Fully initialize the dev_info before adding it to the list.
>>     https://lore.kernel.org/linux-
>> iommu/BN9PR11MB52764D7CD86448C5E4EB46668CAA9@BN9PR11MB5276.
>> namprd11.prod.outlook.com/
>>   - Various code and comments refinement.
>>
> 
> This doesn't say why original patch2 was removed:
> 
> 	"iommu/vt-d: Remove for_each_device_domain()"
> 
> It took me a while to realize that it's already covered by your another
> patch fixing RID2PASID. 😊

My fault! I forgot to mention it in the change log. Sorry about it.

Best regards,
baolu